Supplements for weight loss, do they work? That’s the topic of the day. In this article, I’m going to take a close look at a recent review of supplements marketed as weight loss products, fat-burners, and calorie-blockers. After reading it, you’ll know which ones are worth your hard-earned money, which might have an effect even if it’s not 100 % backed by science yet, and which supplements are safe and which are associated with unpleasant or even harmful effects. Some supplements aren’t worth the water bill for flushing them down the drain. Rest assured that I’ll let you know which ones to stay away from. The conclusions are relevant both for strength-training purposes and for losing weight in general.
The basic rule of losing weight is spelled caloric balance. Calories in minus calories out. You need to expend more calories than you eat to lose weight and body fat. However, that equation tells you little to nothing about what your body uses the calories you eat for. It can’t show how many of the calories you burn come from your body fat stores, your fat-free mass, or the food you eat.
It sure would be neat if you could reach for a legal, safe, and effective pill or powder to help you lose weight when you need to lose some excess body fat, wouldn’t it?
Not long ago, I wrote a similar article that reviews supplements to build muscle: powders and pills that can help you get bigger and stronger. The supplement market for weight loss products is probably several times larger. An overwhelming number of dietary supplements, brands, and proprietary blends all want your money and promise the world. But do they hold to those promises? Read on, and we’ll find out together!
I based the previous article on a comprehensive scientific review article. This article is also inspired by recent scientific material, but this time it’s all about supplements for weight loss and burning fat rather than gaining mass and strength.1
Dietary supplements for losing body fat can be placed into five categories, according to their purported mechanisms:
- Limit or reduce how much of the energy and nutrients you absorb from the food you eat.
- Control your appetite and hunger.
- Increase your energy expenditure.
- “Burn fat” or improve your fat metabolism.
- Increase and improve your carbohydrate metabolism.
Supplements That Limit or Reduce Caloric and Nutrient Uptake and Absorption
Medications that are used to treat obesity and make patients lose weight work, and they work by limiting how much fat your intestines absorb. The medication prevents enzymes in your intestines from breaking down the fat in your diet properly. Since fat is very calorie-dense, this means that a significant number of the calories you eat end up in the toilet. The most famous, or infamous, of these obesity medications is probably Orlistat.
Some dietary supplements intended for weight loss work according to the same mechanisms. They prevent or delay the uptake of fat, and in some cases carbohydrates as well, from your intestines. This also affects gastric emptying and makes you feel fuller.
Green tea is produced from the leaves of the camellia shrub, much like any other tea. However, green teas aren’t fermented and oxidized to the same extent as black tea. Chinese literature dating as far back as 1,000 years documents numerous purported health effects from drinking green tea.
In tea, you find natural chemicals called catechins. Catechins are anti-oxidative phenols. In the western hemisphere, the main source of catechins in the average diet is tea. Plenty of studies show that green tea catechins are biologically active in several ways. They inhibit an enzyme shown to be overrepresented in several forms of cancer and protects against mechanisms implicated in heart disease and neurodegenerative conditions.
In theory and test tubes, that is. Green tea is promising in several health-related areas, but not proven effective to treat or prevent diseases in practice.
Another claimed effect of green tea is weight loss and obesity prevention. Many studies, most of them with rodent participants, show that green tea produces effects similar to obesity medications like Orlistat. The tongue-wrenching catechin epigallocatechin-3-gallate, or EGCG for short, binds to enzymes in your intestine and both reduces the amount of fat you absorb and limits the formation of fat cells. This leads to your caloric intake dropping without you noticing it, besides having oiler than usual trips to the toilet.
EGCG also inhibits the two enzymes amylase and glucosidase. They are responsible for breaking down carbohydrates, which means that green tea not only limits fat absorption but carbohydrate absorption as well.
This all sounds well and good, but does it work? Do you lose more weight and fat by drinking green tea?
Probably, yes. A systematic review and a meta-analysis, both of them published during the last three years, conclude that claims for weight loss from green tea have scientific support. The majority of the studies with human subjects show that green tea helps significantly in this regard.
Daily consumption of green tea containing 100 to 460 milligrams of EGCG per day leads to significant and measurable weight loss. Especially if we’re talking about a long time, say 3 to 4 months.
A recent eight-week study demonstrated that women who took up weight training improved their body composition more than a placebo control group when they combined the exercise with green tea.
One factor to take into consideration here is caffeine. Green tea contains caffeine, different amounts depending on the brand. In general, one cup of green tea gives you half as much caffeine as a similar-sized cup of coffee. Caffeine in itself can be at least partly responsible for the effects here, especially if you aren’t used to caffeine and suddenly introduce hundreds of milligrams every day from green tea.
So yes, green tea can help with weight loss. However, don’t rely on green tea to maintain your weight loss, regardless of how you lost it. One meta-analysis found zero evidence that neither green tea nor the EGCH-catechin itself prevents weight regain.
In summary, don’t expect green tea to do the job for you. It won’t make or break your diet or your efforts to lose weight. However, you might receive a small but useful helping hand if you drink green tea regularly. Also, green tea is safe with few to no side effects, which makes it a promising supplement for weight loss purposes.
Speaking of side effects, let me elaborate on the safety of green tea. Some research indicates that green tea protects against non-alcoholic fatty liver disease. On the other hand, other studies associate a high intake of green tea with liver damage. Most of those reports are case-studies of persons drinking witches’ brews of numerous different ingredients with green tea being one of many. Because of that, it’s difficult to isolate a certain ingredient as being responsible for the liver taking a hit. Currently, no evidence suggests that green tea in particular causes liver damage, but it might be something to keep in mind.
The root of the ginseng plant has been used for medicinal purposes in Asia for hundreds of years. Nowadays it is also a common dietary supplement in the rest of the world. The claimed health benefits of ginseng include stronger immune functions, improved memory, mental focus, better physical performance, and more energy in general. Some of the health-related effects of the ginseng root lack convincing scientific support. Others lack any scientific support at all.
Some of the active compounds in the ginseng root could be of use for weight loss purposes. These include chemicals called saponins, which delay the uptake of the fat you eat by making your pancreas release less of an enzyme that breaks down the fat molecules.
In obese mice, ginseng affects hormones like leptin, ghrelin, and adiponectin. These are hormones that control your hunger, appetite, and how full you feel.
However, very few high-quality human studies lend support to claims that ginseng helps you lose weight.
One exception is a randomized, double-blind trial where overweight women supplemented with red Korean ginseng for eight weeks. Compared to placebo, their BMI dropped, and the amount of food they ate decreased. Also, they reported improved quality of life at the end of the study. The women received a massive dose of ginseng, a whopping 18 grams per day. A standard dose is somewhere around 400–500 milligrams per dag.
In another study, diabetic patients received 200 milligrams of Korean ginseng. While the supplement improved their blood glucose control, it did nothing for their body weight compared to a placebo.
Lastly, a recent 12-week study saw no effects on BMI, body weight, body fat, blood glucose, or insulin levels in subjects receiving a high daily dose of 6 grams of Korean ginseng.
In summary, the available studies on ginseng and weight loss are not always of the highest quality. On the contrary. Also, the doses used vary a lot from trial to trial. If you are thinking about trying a ginseng supplement, you should probably not expect weight loss as a result. At least not if you want scientific support for your supplements.
White Kidney Bean
I’m sure you don’t need an introduction to white kidney beans. Beans in general are great and nutritious: filled with quite good protein and some of the most high-quality carbohydrates you can find. Also, they come brimming with many bioactive chemicals like polyphenols, oligosaccharides, and lectins. Out of these, lectins might be a double-edged sword. While they have anti-tumor and anti-obesity properties, they are also toxic allergens. Fortunately, you eliminate their negative effects if you soak them properly before cooking them.
Beans are filling little things, and they are good for your blood sugar and insulin. They affect your gut microbiota in a way associated with improved weight loss. Good food when you’re trying to lose weight, in other words.
However, we’re talking about supplements here. In supplement form, white kidney beans come in the form of bean extract which isolates the effects of a so-called amylase inhibitor. This means that you don’t break down starchy carbohydrates as efficiently, leading to more carb calories ending up in the toilet rather than as energy for your body.
Scientists documented these effects a long time ago, way back in the middle of the 1980s. Since then, several follow-up studies have been published. A 2018 meta-analysis concluded that white kidney bean extract leads to fat loss and a weight loss of up to 3 kilograms in overweight subjects when taken with carbohydrate-rich meals.
An older meta-analysis did not find any significant differences in weight loss between white kidney bean extract and placebo. Of course, it had less material to work with than the new analysis.
In summary, the review I based this article on concludes that even though the evidence is of moderate quality, white kidney bean extract might indeed help you lose weight. One to three grams per day provides a clinically significant effect.
Chitosan is a polysaccharide extracted from the shells of crabs and shrimp. It has at least one confirmed positive health benefit. In 2011, the European Food Safety Authority published an extensive assessment, concluding that chitosan helps maintain normal LDL-cholesterol levels. In the same assessment, they also looked at claims that chitosan aids weight loss. Their verdict was not positive, with no apparent cause and effect relationship.2
Since chitosan is said to lead to weight loss by manipulating blood cholesterol, we’re not off to a promising start.
In rats and mice, chitosan decreases the amount of dietary cholesterol absorbed, and in a test tube, it prevents fat cells from growing.
As for humans, we find some support for chitosan as a weight loss supplement in a meta-analysis. It looked at 14 studies, but those were low-quality trials, and the differences compared to placebo both unclear and quite small.
So, very little convincing evidence suggests any use for chitosan during a diet. If you have more money than you need, it won’t do any harm. Still, it’s not possible to either recommend or discourage the use of chitosan to lose weight at the time of writing this.
Beta-glucans are fibers or polysaccharides found in the cell walls of everything from bacteria to algae to cereal grains like oats and barley.
When you include beta-glucans in a meal, you slow down the rate you absorb fat and carbohydrate. In the long run, this can lead to lower and improved levels of blood glucose and lipids. Beta-glucan supplements show promise as part of the treatment of diabetes and hyperlipidemia, which is when you have too much fat in your blood.
The combination of a slower uptake of carbs and fats and the fact that a couple of studies show increased satiety in obese mice has led to speculations that beta-glucans might help you lose weight.
At the moment of writing this, those speculations remain speculations. In a single placebo-controlled trial, overweight women received a beta-glucan supplement in addition to a low-calorie diet. They didn’t lose any more weight than a control group receiving a placebo. Another study demonstrated an appetite-lowering effect but didn’t check if that had any relevance to real-life weight loss efforts.
This means that when you see claims of how much beta-glucans help you lose fat and weight, keep in mind that those claims are not backed by science.
If it’s a water-soluble fiber you want, look no further than psyllium. When it dissolves, either in water before ingestion or in your intestines, it forms a thick gel. This gel slows gastric emptying down and makes you feel full for longer. Also, it can improve your blood sugar control.
A couple of studies show that psyllium disrupts the absorption of carbohydrates from your food a bit.
Two brand new critical reviews show that psyllium and psyllium supplements may lead to a modest weight loss. Especially if you consume them daily for at least six months, in combination with exercise and a good diet.
An even more recent meta-analysis conducted by Chinese scientists does not come to the same conclusions. It couldn’t find any effects of psyllium on BMI or bodyweight at all. However, it’s not much of a meta-analysis, having a total of only four studies available for analysis. Since it limited the analysis to placebo-controlled trials, that’s the amount the researchers had to work with. In any case, the limited amount of research could explain the discrepancies between the Chinese meta-analysis and the other two reviews. Of course, placebo-controlled trials are worth more when it comes to scientific evidence. A few high-quality trials trump many low-quality studies.
We have one more meta-analysis evaluating the effects of psyllium on weight loss. Just like the others, this meta-analysis is brand new, and it covers almost three times as many studies as the Chinese one. It does not limit the analysis to placebo-controlled research, which means a whole lot more material. The results show that psyllium lowers BMI a bit, but not significantly. That means that the positive results might just as well have been a coincidence. A closer look at included subgroups suggests that a high dose of psyllium, more than 10 grams per day, does lower BMI significantly, as long as the psyllium intervention lasts longer than 10 weeks.
In summary, high-quality psyllium studies are far and few in between, and the effect is, at best, modest. Because of that, we can’t recommend psyllium for losing weight and body fat.
However, this does not mean you need to avoid psyllium. On the contrary, psyllium has other documented and positive effects. It improves blood sugar control and lowers insulin levels, and offers relief both if you are constipated or suffer from temporary diarrhea. Also, psyllium seeds protect the colon and improve intestinal inflammation, at least in mice.3
Here we have another water-soluble fiber. Glucomannan is a polysaccharide from the cell walls of certain plants. Glucomannan as a dietary supplement usually hails from the tuber Amorphophallus konjac.
The fiber from glucomannan absorbs an astonishing amount of water, up to 50 times its weight. Also, neither saliva nor pancreatic juice breaks it down, meaning it enters your colon undigested where your intestinal bacteria can go to town on it and begin the fermentation process.
Glucomannan is supposed to help you lose weight by delaying your gastric emptying and making you feel fuller. It’s also supposed to lower your appetite and make you eat less.
Does it work? Maybe. Two meta-analyses lend support for glucomannan supplements to lose weight. They show that 1–4 grams of glucomannan per day lead to significant weight loss in overweight subjects, compared to placebo. However, more recent reviews and meta-analyses come to the opposite conclusion: glucomannan does not lead to any weight loss worth mentioning, no more than a placebo.
Almost all glucomannan weight loss studies are small-scale and underpowered, providing low-quality evidence regardless of the outcome. That’s why it’s not possible to say yay or nay when it comes to glucomannan as a supplement for weight loss at the moment.
More fiber, you say? Absolutely. This time it’s a fiber extracted from the legume Cyamopsis tetragonoloba, mostly found and cultivated in India. Guar gum is extensively used as a thickening agent in the food industry, but you can also find it in weight loss products. There, it is used because it thickens the contents of your stomach, leading to increased satiety and improved appetite control.
That’s in theory, anyway. For actual weight loss, guar gum doesn’t seem very promising. One meta-analysis saw zero advantages compared to placebo even with intakes as high as 30 grams per day over 6 months.
Guar gum isn’t completely without benefits, though, seeing as the participants in the trials improved their insulin sensitivity and cholesterol status in addition to feeling fuller. Unfortunately, these effects did not translate into weight loss.
You might get certain side effects from guar gum. These aren’t dangerous, but studies report unpleasant ones like a painful and gassy stomach, diarrhea, and flatulence.
The gelatinous substance agar is extracted from algae and forms a mixture of different polysaccharides. This concoction is very rich in fiber, making it useful in the food industry as a thickening agent and when you’re making puddings and custards. As a bonus feature, you can use agar as a laxative, since your digestive system can’t break it down.
If you add agar to a meal, your gastric emptying slows down and your satiety increases. Funnily enough, one study showed that agar as part of a mixed meal had the opposite effect. It increased the participants’ desire to eat. Maybe not the best outcome if you’re aiming for weight loss.
With agar, we have no meta-analyses to fall back on. Well, there is one, but it only mentions agar in passing while reviewing the effects of soluble fiber on weight loss in general.
Neither are there any quality trials with healthy, human subjects available. One 16-week study demonstrated that 180 grams of agar per day led to a weight loss of 4.4 %, compared to 2 % in the placebo group. Those subjects were untrained diabetics with impaired glucose tolerance. While there is nothing wrong with investigating the effects in that population, the results are likely not applicable to a healthy, maybe young, person engaging in strength training.
This all means that, currently, there is no evidence that agar is a useful dietary supplement if you want to lose weight.
Inulin and Other Fructans
A fructan is a polymer made up of fructose molecules, often from rye, wheat, onions, or garlic. One of these fructans is called inulin, often used in the food industry as a replacement for fat and sugar, and to modify the texture of various food products. It is also used to add fiber to the diet and as a supplement. In supplement form, inulin usually comes from the chicory plant.
Inulin affects your intestinal bacteria in a way associated with increased satiety, weight loss, and a decrease in systemic inflammation. Also, inulin has a hand in regulating hormones associated with satiety, like ghrelin
Unlike with some other supplements, we have a plethora of research to help us decide if inulin is useful for weight loss.
A 2013 article reviewed 15 randomized controlled trials, but couldn’t find more than 2 where the participants lost weight. Even less encouraging, only one study demonstrated any significant effect of inulin on satiety and appetite.
In 2017, a meta-analysis found that 10 grams of inulin per day lead to weight loss and increased satiety in diabetics. However, the results for healthy individuals were not encouraging.
A later study showed that inulin decreases ad-libitum (unrestricted) eating. Unfortunately, this effect required a whole lot of inulin, no less than 30 grams per day. That amount might lead to you eating less, but it also leads to flatulence and possibly diarrhea. The study found no effect of inulin if you control your caloric intake.
So, inulin to lose weight or body fat, yay or nay? Nyay. If you are diabetic, you might benefit from inulin, but otherwise, the evidence is weak.
Supplements That Regulate Appetite
Hunger, satiety, and fullness are crucial aspects of a successful weight loss. Maybe not if you are a competitive bodybuilder with your sight on the stage. If you are, you probably ignore such worldly things. However, the vast dieting majority don’t count every calorie. Instead, they depend on feelings of hunger and fullness to tell them when and how much to eat.
If a dietary supplement could improve satiety and reduce cravings without any side effects, plenty of people would use it with little hesitation. In this category, we take a look at supplements claiming to do just that.
The edible cactus Caralluma grows in India and parts of Europe and Africa. Traditionally, it is used to reduce hunger pangs and appetite during periods of food shortage.
In rats, this cactus seems to decrease appetite and reduce the amount of food the rodents chow down spontaneously. Also, overfed rats gain less fat and body weight when you add Caralluma to their diet.
Human research is less than plentiful. Two studies suggest weight loss by supplementing with one gram of Caralluma per day for two months, but another and longer study found no effect at all using the same dose.
Few studies and low-quality evidence pointing now this way and now that way means a supplement not recommended for weight and fat loss. One positive aspect of Caralluma is that there are no known side effects of partaking of this cactus.
The blue-green algae spirulina is used both as a food source for humans and animals as well as a dietary supplement. It is one of very few completely plant-based protein sources providing every amino acid you need to build muscle and other tissue in plentiful amounts. Spirulina also contains enormous amounts of nutrients and chemicals like vitamins, minerals, essential fatty acids, and antioxidants. For example, spirulina provides 5,000 % more iron than spinach and 3,000 % more beta-carotene than carrots.
Animal trials show that spirulina regulates many mechanisms controlling body weight. Spirulina extract slows down fat cell growth, transforms white, inactive fat to brown, active fat, and changes genes in the liver and brain that affect food intake and energy metabolism.
In humans and for weight loss purposes, spirulina is mostly used as an appetite suppressant.
If and how well spirulina works for weight loss outside of a lab is currently unknown. A recent review article and meta-analysis took a look at the available research but found only 5 randomized controlled studies published over 20 years. This means that human research is sparse, to say the least.
In general, the meta-analysis indicated that 1–4.5 grams of spirulina extract per day for up to 12 weeks lead to a weight loss of about 1.5 kilograms, lower body fat, and reduced waist size, compared to placebo. Sounds great, right? Unfortunately, the results are based on those 5 studies over 20 years, meaning that they are likely quite unreliable.
Spirulina supplements have potential side effects like stomach issues and headaches. Long-term use can even lead to liver damage, even if side effects that bad are rare. These negative side effects are not from the spirulina algae itself, but from contamination by other algae. Also, contamination by arsenic and metals like lead and mercury have been observed.
The risk of getting unpleasant things like that with your spirulina extract, along with the limited amount of available research, means that spirulina can’t be recommended as a supplement.
Most of you reading this probably already know about whey protein. If you engage in strength training and use a protein supplement, chances are you are or have been using whey protein, unless you are a vegan. Whey is a very high-quality milk protein, providing you with an abundance of all the amino acids you need to build muscle mass.
Beyond the ability of whey protein to build muscle, it also comes with fat-burning properties and affects satiety hormones more than most other proteins.
Several meta-analyses offer support for whey protein for weight loss purposes, with or without strength training as part of the picture. Participants eating or drinking 100 to 600 grams of whey protein per week lose more weight and more body fat than participants eating the same number of calories from placebo (usually carbohydrate). A recent meta-analysis suggests that only whey protein concentrate reduces body fat, though, not whey protein isolate or hydrolysate
The evidence supporting the use of whey protein to lose weight is not of the very highest quality, but neither is it low. “Moderate” seems like a good way to describe it. So, yes, there is scientific support for claims that whey protein can help you lose body fat as part of a good diet plan. If you engage in strength training, this means that you might have more uses for your whey protein supplement than for gaining muscle.
Coffee, Caffeine, and Chlorogenic Acid
Most likely, coffee and caffeine need little to no introduction. We’re talking about one of the most popular beverages in the world, except for water, and the most popular drug.
Caffeine offers several known compounds and mechanisms that can aid in weight loss. It increases the number of calories you burn, lowers your appetite, and increases your fat oxidation. The chlorogenic acid in coffee beans possesses both anti-inflammatory and antioxidative properties, lowering the levels of fat and sugar in your blood. Green coffee provides you with a lot more chlorogenic acid than black.
Besides, don’t discount the performance boost you get from caffeine. If you can train harder and longer, you burn more calories.
A recent meta-analysis of 13 trials published between 1999 and 2014 found that caffeine reduces body weight, BMI, and body fat. This effect is dose-dependent, meaning that more caffeine leads to greater weight loss. One problem with this review is the fact that it analyzes studies both on pure caffeine and studies where the participants got their caffeine from coffee. Sometimes, they even added ephedrine to the study protocol. This makes it hard to isolate the effects of a certain substance. Coffee contains more than 1,000 chemicals, not just caffeine. And those are only the ones we know about. Add medications like ephedrine to the mix, and you end up with a brew from a witches cauldron rather than a health- and performance-promoting beverage.
One study found that green coffee, which provides you with more chlorogenic acid than regular black coffee, leads to a larger weight loss. In that study, both black and green coffee reduced the participants’ abdominal fat, even though they didn’t change their caloric intake or their physical activity. At least they didn’t report any changes, although we all know how reliable such reports are.
Also, several studies show that green coffee extract counteracts weight gain.
In summary, fairly high-quality evidence shows that coffee, both regular black or green coffee, as well as supplementing with pure caffeine or chlorogenic acid, are worth considering as part of a weight-loss diet. They might provide some help along the road to a slimmer you. However, current research doesn’t reveal how much of that potential effect can be attributed to the various components of coffee.
If you want coffee to aid your weight loss efforts, it goes without saying that black (or green) coffee without milk, cream or sugar is preferable. If you drink a lot of coffee and add sugar and cream to every cup, the calories will add up very fast.
This citrus fruit is filled with synephrine, a substance similar to ephedrine which is extensively used for weight loss purposes.
A couple of studies show that bitter orange extract leads to weight loss, either on its own or as part of a multi-ingredient weight loss supplement. In 2011, a scientific review concluded that both an extract from bitter orange in general and synephrine are safe without any significant side-effects.
Even if the supplement is safe, the latest and largest overview, featuring more than 30 trials with more than 600 subjects suggests that bitter orange extract simply isn’t effective. The evidence for weight and fat loss is questionable and limited. Also, bitter orange supplements often contain many other ingredients, making it impossible to isolate any effects to a certain substance. Synephrine itself does not have any cardiovascular effects below doses of 100 milligrams, and then we’re talking about quite high and potentially unpleasant amounts.
At the time of writing, there is little to no evidence that bitter orange extract helps you get into shape. The fruit itself is bitter enough to be inedible.
Guarana is a plant native to the Amazonas. Both the fruit and the seed contain large amounts of catechins and so-called xanthines, from which you can extract caffeine. These chemicals inhibit fat cell growth and turn white fat tissue into healthy brown fat, at least in animals. In humans, they increase energy expenditure.
Despite the evidence for guarana having the potential to start these metabolic processes, there is no evidence that guarana by itself leads to weight loss in humans.
One double-blind study showed that guarana in doses of close to 300 milligrams per day led to significant short-term weight and fat loss. However, almost 25 % of the subjects withdrew from the trial, complaining about side-effects like headaches and sleeping issues. Also, the supplements contained ephedrine as well as guarana, which makes it hard to say anything about the effects of the guarana itself.
In another study, the subjects received guarana in the form of an herbal supplement. This experiment resulted in increased satiety, slower gastric emptying, and weight loss. Once again, however, the supplement contained other active ingredients as well. A number of them, in this case.
Human data lending support for guarana as a weight loss supplement is sparse, in other words. The few studies suggesting a positive effect also include other and maybe more powerful substances along with the guarana supplement. The effects are unclear, the evidence of low quality, and you probably shouldn’t buy into claims that guarana is any kind of key to weight loss.
Supplements That Increase Energy Expenditure
Imagine that you could increase the number of calories you burn without any extra effort. Sounds enticing, doesn’t it? Especially if it was possible using only legal dietary supplements without any side effects.
Unfortunately, fantasies like this are often crushed when reality sets in. Sure, caffeine and a few other supplements might increase your energy expenditure a bit, but those effects are pretty modest. Even the most powerful legal “fat burners” on the market rarely burn more calories than taking the stairs instead of the elevator.
If you want to manipulate your caloric balance without radical changes in your diet or your physical activity, you would have to play around with your hormones. If you do, you’re on thin ice. Also, any “supplement” capable of manipulating your hormones is a prescription medicine.
However, some substances have a small but maybe significant effect in this regard, when combined with a decent diet plan. They are also legal and natural. Let’s take a look, shall we?
Capsaicin, Capsaicinoids, and Capsinoids
You’ve probably familiar with capsaicin already. You might use it regularly in your kitchen. Capsaicin is a compound found in chili peppers. When you feel that burn in your mouth when you eat hot food, you feel capsaicin working its magic.
Capsaicin is part of the family called capsaicinoids, along with other compounds. These work through similar mechanisms and bind to the same receptors. Because of structural differences, they don’t reach the receptors in your mouth and don’t cause the same burning sensation as chili peppers.
Capsaicin and capsaicinoids have several effects with potential interest for weight and fat loss purposes. Most of these are backed by scientific evidence.
Three meta-analyses from 2014 to 2018 concluded that capsaicin and capsaicinoids, when taken in doses between 10–36 milligrams per day, increase your body temperature and your resting energy expenditure by 50–70 kcals, also per day.
Also, using a capsaicin supplement usually reduces caloric intake by about 74 calories per day, with higher doses leading to further reductions.
These effects are most prominent in overweight individuals with a BMI higher than 25. This might be because the sympathetic nervous system is depressed in obese individuals, increasing the effects of capsaicin.
High-quality evidence shows that capsaicin and capsaicinoids affect energy balance through thermogenic mechanisms, and might reduce food intake. At least in the short term. We don’t know if these effects lead to long-term weight loss. If you manipulate your caloric balance over a short period, like a day or so, your body usually compensates for this over time. Long-term studies on this subject are not of the same quality and ambiguous.
Chili extract (and chili peppers themselves) are safe, and if you like your food hot and spicy, you can kill two birds with one stone. Capsaicin and capsaicinoids have potential as weight loss agents. If you don’t like hot food, the extra fat oxidation and increased energy expenditure you might gain is probably not enough for you to torture yourself.
Curcumin is a polyphenol found in turmeric. It gives turmeric a distinct golden yellow color. In the form of turmeric, you can find curcumin in curry, and the food industry uses it for different purposes in many foods. Curcumin is an antioxidant able to kill cancer cells in test tubes and slow the growth of tumors in mice. Potential health benefits to be found, in other words. Unfortunately, as is often the case, human studies confirming these effects are nowhere to be found.
A meta-analysis of 21 randomized controlled studies shows that curcumin reduces BMI, body weight, and waist circumference. These results come from studies with few participants and which use a form of curcumin with poor absorption. Following this meta-analysis, no newer studies have found any effects related to weight loss from curcumin supplementation in doses of up to 1 gram per day.
Low-dose curcumin supplementation is safe, and high-dose supplementation seems to have only mild side effects like nausea and stomach issues. However, the use of curcumin to lose weight is not supported by any high-quality scientific evidence. Don’t expect any help from curcumin in your weight loss efforts.
L-carnitine is a non-essential amino acid, meaning your body can make it on its own, from two other amino acids: L-lysine, and L-methionine. You don’t have to provide L-carnitine through your diet, but you do so anyway. Animal proteins like meat, fish, and dairy in particular contain a lot of L-carnitine. You get more L-carnitine than you need for regular purposes without any supplement.
As a dietary supplement, L-carnitine is popular as a weight loss product. It has indirect scientific support in that it protects against insulin resistance and improves energy metabolism in animals. A few human studies show increased fat oxidation and energy expenditure as well. Also, L-carnitine transports fatty acids into your mitochondria, helping your body to break down fat.
L-carnitine weight loss research is ambivalent, to say the least. Several studies find no effect at all, while others do. Two meta-analyses published in the last five years conclude that L-carnitine might help reduce both body weight and body fat, even if these effects decrease over time.
Human L-carnitine studies are generally of pretty low quality. They use wildly varying doses of the supplement, anything from 10 milligrams per day to 4 grams per day. A closer analysis suggests that if L-carnitine has any kind of significant effect, it’s probably more useful for overweight and obese individuals, not someone who wants to lose a few pounds before beach season kicks off.
Supplements That “Burn Fat” and Improve Fat Metabolism
Losing weight without losing fat is not something to strive for, not if your goal is to look better. Plenty of weight loss supplements are sold as “fat-burners”. They rarely live up to marketing promises, at least not with scientific backing from human trials. In the next section, we look at some of the most common of these supplements.
Pyruvate, a derivative of pyruvic acid, is said to decrease the number of calories you “burn” from carbohydrates, shifting that energy expenditure to fat instead. You get pyruvate from regular food and drink like cheese, apples, and red wine.
Animal studies show that pyruvate supplements lower insulin levels and increase fat oxidation. A 2014 meta-analysis lends support to these effects in humans, too, resulting in greater weight and fat loss in subjects using pyruvate compared to placebo.
The studies available for analysis are few and the demonstrated effects modest. Also, they provide fairly low-quality evidence, and they are at least 15 years old. After 2005, weight loss studies on pyruvate stopped being conducted and published, for some unknown reason.
In summary, no fresh research supports pyruvate supplements for weight and fat loss. The early research is largely irrelevant due to low quality. In other words, don’t bet your savings on pyruvate.
From various oils, like cottonseed oil and rapeseed oil, you get a component called diacylglycerol. It increases fat oxidation, at least in mice. As a weight-loss supplement, it has support from several meta-analyses.
Diacylglycerol might reduce body weight and limit weight gain during overeating, according to several studies. These studies suggest that supplementing with diacylglycerol on its own or together with other supplements, like alpha-linolenic acid, leads to lower body weight, less abdominal fat, and a smaller waistline, both in diabetics and healthy individuals. Even better, no negative side-effects have been reported, and the quality of the available studies is fairly high.
In other words, diacylglycerol belongs to the few supplements that could promote fat oxidation and weight loss. A daily dose of 1.1–1.2 grams might help you lose both weight and fat.
Love it or hate it, everyone knows about licorice the candy. The distinct flavor of said candy comes from the extract of the roots of the licorice plant. The root contains several bioactive substances, including glycyrrhizin, carbenoxolone, and various flavonoids. Licorice has both positive and negative health effects. For example, it protects your liver in case you are overweight and suffer from non-alcoholic fatty liver disease. On the other hand, licorice increases your blood pressure and lowers your testosterone levels.
Licorice and licorice extract is associated with weight loss, but the potential mechanisms are unclear. One possible mechanism, observed in overfed mice, is the effect of one of the previously mentioned flavonoids, glabridine, which activates a so-called protein kinase by the name of AMPK, leading to increased fat oxidation when the energy levels in cells decrease.
A recent meta-analysis looks at all available research published between 2012 and 2017, a total of 26 studies, and finds that the ingestion of licorice or the extract of licorice leads to a lower body weight after 2–16 weeks. The more licorice, the greater the weight loss. Something else dose-related is the increase in blood pressure. Both blood pressure and blood sodium levels increased in participants using licorice supplements for weight loss.
In general, the available research consists of low-quality studies. A later, better-quality randomized and controlled study with 64 participants found no difference in weight loss in the licorice group compared to a placebo group eating the same low-calorie diet.
The compounds found in licorice likely have properties that could, potentially, affect body weight. Actual, noticeable weight loss from licorice consumption is something else entirely. The available research is conflicting and of low quality. Also, significant amounts of licorice lead to side-effects like higher blood pressure.
Licorice in the form of candy not only gives you the active compounds but 300 kcals per 100 grams of candy at the same time. Hardly compatible with weight loss.
Garcinia Cambogia is a tree bearing fruits with the same name. These fruits have been used for medicinal purposes in India and Sri Lanka, for example, for a very long time, primarily to cure constipation. Eating the fruit of the Garcinia Cambogia tree gives you explosive and watery diarrhea.
The active compound with the potential for weight loss is called hydroxycitric acid or HCA for short. HCA reduces the availability of other substances your body needs to synthesize fatty acids and cholesterol. According to some early studies, HCA also controls genes that could lower fat storage.
A 2018 meta-analysis revealed… well, not a lot. It analyzed 9 randomized controlled trials, but the results of these were so conflicting that the researchers didn’t get anywhere. A few of the studies didn’t see any greater effect from Garcinia Cambogia than from placebo. Some of the others demonstrated lower body fat in the Garcinia Cambogia groups. The doses used in the studies varied a lot, from 400 to 2,400 milligrams per day, the studies lasted from 2 weeks up to 12 weeks, and none of them provided any information about the methodology.
Adding insult to injury, Garcinia Cambogia might not even be safe to use. At least five studies associate the use of an extract from the Garcinia Cambogia fruit with liver damage. Not long ago, the US Food and Drug Administration discouraged the use of the weight loss product Hydroxycut, which at the time contained, among other ingredients, Garcinia Cambogia. In 2009, the product was implicated in 23 cases of liver damage. It contained numerous ingredients, not just Garcinia Cambogia, so picking it out as the sole culprit is not possible.
In any case, we can’t recommend using Garcinia Cambogia as a weight-loss supplement. Or for any other purposes. It might not be of any use for weight-loss purposes, and besides, it could potentially damage your liver.
The natural polyphenol called resveratrol is found in various plants, berries, and nuts. It’s a long-standing medicinal supplement due to purported antioxidative, anti-inflammatory, and even tumor-inhibiting properties.
When you use a resveratrol supplement, you activate an enzyme called SIRT-1. Once that happens, several processes follow, including increased fatty acid oxidation and increased energy expenditure. In mice at least.
One meta-analysis had a thorough look at 36 randomized controlled trials to see if resveratrol has any effect on weight loss in humans. It concluded that supplementation with resveratrol leads to significantly lower body weight, lower BMI, a smaller waist, and less body fat. All these effects were significant, meaning they didn’t just happen by chance. In addition to all that, it increased fat-free mass as well.
Even though this all sounds promising at a glance, a more thorough inspection of the included studies reveals low-quality research. The effects on body weight, body fat, and fat-free mass were also very small. A high significance means that an effect isn’t due solely to chance, not that it is big or small. In this case, the significance was so low that any effects likely have no clinical relevance.
In summary, yes, resveratrol could help you lose weight and body fat. However, don’t expect results you can notice. Any effects are likely so small that they can only be detected in a lab setting, not in real life. One bright spot in an otherwise dreary conclusion is that resveratrol does not seem to have negative side effects.
Conjugated Linoleic Acid (CLA)
CLA, or conjugated linoleic acid, is a group of polyunsaturated fatty acids. You find them mostly in meat and dairy. CLA supplements are a common sight in the weight-loss section of any supplement store. It is a safe supplement, without any negative side effects except possibly slight and transient stomach issues.
Several documented mechanisms lend support for CLA supplementation to lose weight. It reduces the size of fat cells, modulates your fat metabolism, activates fatty acid oxidation, and turns white fat into brown, to mention a few of those mechanisms.
The big question is whether or not these mechanisms, proven in test tubes and animal trials, lead to weight and fat loss in a real-life scenario.
Maybe. Then again, maybe not.
Human CLA trials are a dime a dozen, but ambiguous. They use different types of CLA, and the length of the studies varies from a few weeks to a few years. The dosages used also vary a lot from trial to trial. Also, the number of participants is often low, too low to say much for sure.
A 2018 meta-analysis revealed that 3.4 grams of CLA per day for at least 12 weeks leads to a modest weight loss if you are 44 years old or older. Another review found that the effective type of CLA might be the trans-10,cis-12 variant in particular. It would be interesting to see long-term studies using high doses of this particular isomer in an isolated form, but that study has not yet been conducted.
Does CLA work? Probably yes, it might provide a modest boost to your weight and fat loss. However, this conclusion is based on low-quality scientific evidence, and the effect, if it even exists, is likely small. It’s a safe supplement, so if you have the money and want to give CLA a try, it could also be a supplement worth considering.
But don’t expect something earth-shattering.
The plant Aloe Vera is used for many medicinal and healing purposes. In most cases, there is little to no scientific support for the efficacy of Aloe Vera.
As for claims that Aloe Vera leads to weight loss, there might be something to them. If you are a mouse. Rodents lose weight and abdominal fat and show increased rates of fat oxidation when given Aloe Vera extract.
Human trials reveal that Aloe Vera might improve blood lipids and lower insulin and blood glucose levels. Also, some studies do show greater weight loss following Aloe Vera supplementation compared to placebo, including a large, randomized controlled trial published back in 2013.
Unfortunately, these studies lack one thing: quality. Self-reported energy intakes based on recollection and unreliable methods of measuring body composition do not lend confidence to the results.
This is why Aloe Vera doesn’t rank high on a list of weight loss supplements. We have some scientific support from animal studies, but little in the form of human trials. Also, fresh research suggests that Aloe Vera might not be safe. Some reputable sources, including the International Agency for Research on Cancer, classifies Aloe Vera as possibly carcinogenic to humans.4
Seeds from the flax plant are common ingredients in bread and baked goods. They come loaded with fiber and essential fatty acids and have documented positive health effects. These include improved blood glucose metabolism, lower blood pressure, and a healthier blood lipid profile.
In addition to the above, flaxseed is marketed as a weight-loss supplement. The seeds of the flax plant contain several substances that, both in theory, in a test tube, and animal trials, increase fat oxidation and might decrease body weight. The relevance of these results in a human context is still unclear.
A few years ago, a massive meta-analysis of 45 randomized controlled studies showed that intact flaxseed helps you lose bodyweight, lower your BMI, and slim your waist compared to a placebo. Interestingly, this effect was only apparent from intact seeds. Flaxseed oil had no effects at all. Since whole seeds pass through your body and exit it just as intact as they entered, this probably means that the fiber is the main cause of the effects, not the fatty acid composition or anything else found inside the seeds.
However, intact flaxseed did not improve weight loss for everyone. Only those with a BMI above 27 eating at least 30 grams per day for a longer time than 12 weeks lost weight.
One thing of note is that not a single one of the studies included in the meta-analysis reported the energy intake of the participants. This makes it much harder to come to any reliable conclusions. Why did only those who ate intact seeds lose weight? Was it because of the fiber? And if that is the case, why only in participants with a BMI of 27 or higher?
As previously mentioned, flaxseed has several positive effects, not the least keeping your digestive system in shape. If you decide to try supplementing with them to lose weight, go right ahead. Just don’t use ground flaxseed in any significant amounts. They produce cyanide in your body. Cyanide is not good, and there are no safe levels. Flaxseed oil does not produce any harmful substances, but on the other hand, it doesn’t seem to promote weight loss either.
Citrus fruits in general are excellent sources of micronutrients like polyphenols and flavonoids. Grapefruit is no exception. These nutrients act as antioxidants and can improve blood pressure and blood lipids in both animals and humans. In animal trials and test-tube experiments, grapefruit extract even shows fat-burning potential.
In 2017, a meta-analysis looked at the available grapefruit research on weight loss and body composition. Unfortunately, the authors only found three studies on the subject. This meager selection showed that grapefruit might reduce body fat and waist circumference a bit, but does not seem to reduce body weight.
In one of the studies analyzed, the 24 overweight subjects did lose weight when they ate half a grapefruit before their regular meals. A control group drinking grapefruit juice or ingesting grapefruit extract did not lose any weight. This suggests that eating intact grapefruit before a meal leads to eating fewer calories from regular food. However, the study did not report any difference in caloric intake between the groups. In other words, possible mechanisms remain to be revealed.
Does grapefruit help you lose weight or speed up your fat loss? Probably not, even though a limited amount of low-quality evidence suggests otherwise.
One method that works is the classic grapefruit diet. It entails replacing most of your regular meals with grapefruit. This lowers your caloric intake drastically, leading to unavoidable weight loss. However, it’s probably not a healthy alternative and not one that lets you perform properly in the gym or keep your muscles.
Supplements That Improve Carbohydrate Metabolism
How much dietary fat you store and how much fat you “burn” during physical activity are not the only things determining your weight and body fat levels. Insulin resistance and sub-optimal glucose metabolism are two significant risk factors for weight gain and obesity. They also make it harder to lose weight.
Are there any dietary supplements that help your body handle carbs and sugars? Let’s find out.
What do we have here? The answer is a tropical fruit from south-eastern Asia, about the size of a clementine and used for centuries for medicinal purposes. It contains substances with antioxidative properties, and popular media sometimes portrays the fruit and its juice as something of a miracle cure for various ailments. There is no scientific support for any such claims.
Animal trials and test-tube studies reveal that mangosteen possesses certain qualities that kill young preadipocytes (baby fat cells) and lower blood sugar levels. This could help facilitate fat loss. One study showed that rodents lost weight and liver fat when given some of the chemicals found in mangosteen.
Four human studies, where the participants ingested 200–400 milligrams of mangosteen extract per day, showed that they lost more weight and shrunk their waistlines more than control groups given a placebo, without any side effects.
While those studies sound promising, they are way too few and don’t have enough participants to be convincing. Certainly not enough to recommend mangosteen for weight loss. It might have some effect, but then again, it might not. Currently, the available research is not sufficient to tell.
Chromium is not just a supplement, but an essential nutrient. It’s well established that you need to get it through your diet, but how it interacts with your body once inside it is poorly researched and understood. Some countries don’t have a set Recommended Daily Intake value for chromium.
You can also get chromium from supplements. In supplement form, chromium is often marketed for weight-loss purposes. Chromium might stimulate your insulin activity, decrease your appetite, and increase your energy expenditure, according to those marketing claims.
A 2019 meta-analysis of 19 studies with more than 1,300 participants investigated the effects of chromium supplementation on body composition. The results showed that 400 milligrams of supplemental chromium per day lead to significant weight and fat loss in less than 13 weeks in overweight individuals. After that, the weight loss slows down.
An earlier meta-analysis came to a different conclusion. The authors observed that chromium reduced body weight by up to a kilogram, but also that it took 16 weeks to do so. One issue with this meta-analysis is that it included trials where chromium was not the only active ingredient. As usual, this makes it hard to isolate any effects to a particular compound.
These two meta-analyses report no negative side effects. However, earlier research implicates high-dose chromium picolinate supplementation in cases of liver and kidney damage. As usual, causality does not mean cause-and-effect. The safety profile of chromium is still unclear, in other words. There is no set upper tolerable limit (UL). Besides, you absorb chromium from supplements quite poorly, and then you pee most of the chromium you do absorb into the toilet anyway. Recommended doses shouldn’t be harmful, but you should be aware that there are unresolved issues regarding safety.
The quality of the evidence supporting chromium for weight-loss purposes is moderate. The practical relevance, however, is not convincing. Several studies failed to demonstrate any effects of chromium on body weight and body fat. One study even showed weight gain after supplementing with chromium. Taken together, the evidence is not convincing enough for a recommendation at this time.
Lipoic Acid is a powerful antioxidant, capable of improving your insulin sensitivity quite a bit. If you are a diabetic, you can expect to improve your insulin sensitivity by up to 50% using lipoic acid. In some countries, lipoic acid is sold as a prescription medication for this purpose.
Enzymes in your mitochondria can make lipoic acid from the polyunsaturated fatty acid caprylic acid. You also get it from meat and offal. Fruit and vegetables contain some, too, but only in limited amounts.
As a supplement, lipoic acid lowers your blood glucose, but it’s not clear how effective it is for weight-loss purposes. A 2017 meta-analysis of 10 randomized placebo-controlled trials found a small but significant short-term effect.
A year later, another meta-analysis came to a slightly more positive conclusion. An analysis of 12 studies found that lipoic acid leads to significantly lower body weight and BMI. The overall results suggested an average weight loss of slightly more than 1 kilogram after a couple of months compared to placebo.
As with many of these supplements, the evidence is of fairly low quality. According to one of the meta-analyses, supplemental lipoic acid is far from cost-efficient.
At least it’s safe. Up to 1,200 milligrams per day seems to be a perfectly safe dose. Double that dose did not produce any negative side effects compared to placebo in several long-term studies.
The authors of the review suggest the following supplements to help you lose weight and burn fat:
- To prevent the absorption of fat and carbohydrate from the intestine, they recommend 1,000 milligrams of white kidney bean extract along with every meal, with a total daily intake of 3,000 milligrams. They also consider 500 milligrams per day of EGCG from green tea to be a good idea.
- To suppress your appetite and possibly to increase your energy expenditure, the authors suggest you get 300 milligrams of caffeine and 200 milligrams of chlorogenic acid from coffee every day. In addition to that, you might want to consider 10 milligrams of capsaicinoids and 3 milligrams of capsaicin from chili peppers or chili extract each day, along with 2 grams of L-carnitine.
- Moving on, the authors recommend resveratrol and CLA, 200 and 4,000 milligrams per day, respectively, to prevent fat gain.
- Lastly, they think it’s a good idea to improve your carbohydrate metabolism by using 600 milligrams of lipoic acid per day.
My Thoughts on This Supplement Protocol
That’s a lot of supplements, and probably a lot of money, for what is almost certainly, at best, a moderate effect. If you have too much money and wonder how to get rid of the excess, sure, go right ahead. The supplements recommended by the authors have few to no side effects, and they can probably offer some sort of small helping hand in your effort to get in shape. The keyword here is small. If you read the entire article up to this point, I’m sure you have noticed a certain pattern by now. The available research is often methodologically poor, the studies underpowered, and the evidence, where there is any, of low quality.
In no way do you need any supplements to burn fat, lose weight, and get in shape. They won’t do any of the necessary hard work for you. I would go so far as to say that you probably won’t notice them, beyond maybe a placebo effect. An effect measurable in a lab? Sure. An effect you can measure and notice at home? Maybe, in a few cases. A determining factor of success? Never.
My recommendations are more modest. Coffee or caffeine for the performance-enhancing effect, whey protein for building muscle, natural white kidney beans because they are nutritious, and psyllium for gut health and pooping regularly, if needed. With any luck, you might get a small fat-burning boost on top of that.
The foundation of any weight loss diet is always your diet, in combination with the exercise you do. Supplements for weight-loss purposes are of dubious worth, at best. The supplements the authors recommend make such an extensive list that it’s tempting to think they are paid to recommend them. However, this is not the case. They did not receive any outside funding.
Feel free to experiment with different supplements to boost your weight and fat loss, at least out of those without any significant side effects. It’s your money.
You should be aware that most supplements for weight loss have, at best, limited scientific support. They almost invariably cost more than they are worth, for most people. Low-quality research, underpowered studies, and effects only seen in test tubes and animal studies mean uncertain effects and a likely waste of money in many cases.
- Nutrients 2020, 12(9), 2873; Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review.
- Scientific Opinion on the substantiation of health claims related to chitosan and reduction in body weight (ID 679, 1499), maintenance of normal blood LDL?cholesterol concentrations (ID 4663), reduction of intestinal transit time (ID 4664) and reduction of inflammation (ID 1985) pursuant to Article 13(1) of Regulation (EC) No 1924/2006
- Supplemental psyllium fiber regulates the intestinal barrier and inflammation in normal and colitic mice.
- J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2016 Apr 2; 34(2): 77–96. Aloe vera: A review of toxicity and adverse clinical effects.