Of all of the weight loss products available on the market, none are as misunderstood, improperly marketed, and as misused as fat burners. These controversial pills and powders are meant to be taken in order to drop body fat and suppress your appetite while maintaining muscle tissue. Many of them work, but far more do not.
This page is your guide to navigating the "dirty weight-loss-pill waters" that infest the internet, and help separate the stars from the scams.
For an even more detailed guide on choosing the right one, see our blog post titled What is the Best Fat Burner.. for YOU? w/ Top 10 List.
What are fat burners
Lots of products are marketed as "fat burners," but not all of them work by actually burning fat. In terms of supplements that do burn fat either increase metabolism, or mobilize fatty acids for use as fuel.
Either way, there is no magic pill — or supplement — you can take that simply burns off fat with no effort on your part. An authentic fat-burning supplement must be paired with proper diet and regular exercise, especially if you want to retain muscle.
How fat burners work
Supplements marketed as "fat burners" are largely not regulated by the FDA. They also vary widely in how they function. Generally speaking, you can group them into the following classifications:
A thermogenic fat burner simply elevates your metabolism on its own. Strong doses of thermogenics are about as close to a "magic-fat-burning-pill" as science can get. They elevate your ability to burn calories without requiring an increase in physical activity. However, a thermogenic on its own is not likely to help you take off fat because the body doesn't draw its energy solely from fat stores. Thermogenics also increase your risk for side effects, ranging from unpleasant (nervousness or stomach upset), to outright dangerous (irregular heartbeat or dangerously elevated body temperature).
These can really help if you have food cravings above and beyond your daily nutritional needs. They're especially helpful if your goal is to eat below your basal metabolic rate (BMR). But as with thermogenics, simply reducing calories without eating healthy and regular exercise is unlikely to promote significant fat loss.
We've talked a little about how the body draws energy from sources other than fats — for example, from glucose in the blood, glycogen in muscle tissue, and even from breaking down muscle tissue. Lipolytic agents are designed to specifically mobilize the body's fat stores for use as energy.
Diuretics target water weight, which can temporarily make you look slimmer. They don't actually burn fat at all. But that doesn't stop some companies from marketing them as "fat burners," thanks to the aforementioned lack of supplement regulation.
Warning about diuretics
MMA fighters, bodybuilders, and boxers sometimes use diuretics to reduce water weight prior to competition weigh-in. However, they are not appropriate for lasting weight loss, especially if your goal is to improve your health. Diuretics can also have very dangerous side effects when used for long periods of time.
Pure Snake Oil
Unfortunately, with the almost total lack of regulation, it's like the Wild West out there, as far as "fat burning" claims go. The FDA does step in on occasion and ban the sale of supplements that have shown to be a public safety issue, such as ephedra and synthetic DMAA.
Fat burners that are merely ineffective continue to be produced, sold and even endorsed and promoted by people we're supposed to trust, such as Dr. Oz and Oprah (raspberry ketones and acai berry are two prominent examples of "miracle fat burners" that were featured on their shows. Neither supplement ever demonstrated any actual efficacy for weight loss or fat burning in human studies).
Stacking fat burners
Fat burning supplements will frequently contain some combination of these different methods, or will stack with products that offer a different, but complementary, effect. For example, ThyroTwin by Giant Sports is a thermogenic thyroid enhancer that stacks with their lipolytic stimulant Dexamine.
It is extremely important that you do not mix multiple stimulant-based products. For example, fat burners that contain stimulants should never be taken with pre-workout supplements, coffee or tea, or other caffeinated beverages, such as energy drinks. Caffeinated fat burners typically have a strong dose of caffeine. Taking any more could increase your risk of feeling jittery, agitated, or nervous.
Stimulants vs non-stimulants
Fat burners can further be subdivided into those that have added stimulants and those that don't. Stimulants don't do anything in particular to help burn fat, but they tend to make you feel energetic as soon as you take them. The extra energy motivates you to push through a workout. Since stimulants can also make you feel overly anxious, stimulant-based fat burners may worsen your mood and have been known to interfere with motivation.
The primary purpose of caffeine is to produce a quick jolt of energy. But it also has minor thermogenic and lipolytic effects.
In small to moderate doses, caffeine has almost no downsides, unless you're sensitive to it, which is why it's a popular ingredient in fat-burning supplements. However, caffeine reaches its maximum thermogenic and lipolytic effects at very moderate doses — more does not equal better.
Whey protein is often used by bodybuilders as part of a workout formula to gain mass because high-protein diets have been shown to promote lean muscle mass while reducing fat mass.
Whey: did you know?
While any high-protein diet (in tandem with regular workouts) will theoretically promote lean muscle growth and limit body fat storage, whey protein concentrate is popular because it's very low in fat and carbohydrates. It's also relatively inexpensive to produce (it's a cheese byproduct). Since whey has some lactose, those who are intolerant can take whey protein isolate instead, which is further filtered to remove 100% of lactose, as well as fat.
Tea extracts come from green and black teas. They contain some amount of caffeine, but also the compounds EGCG and polymerized polyphenols. These can reduce fat storage and increase fat oxidation.
Capsaicin and cayenne pepper extracts
Capsaicin is what gives chili peppers their heat, and has a thermogenic effect. You'll find it in a lot of fat-burning supplements, or listed as cayenne pepper extract (in which case capsaicin is the active ingredient).
Medium-chain triglyceride (MCT) oil
MCTs are a form of saturated fat that is sent immediately to the liver for processing. Unlike other saturated fats, they cannot be stored as body fat. They're often used as a stimulant and a metabolic booster, but because they give you a feeling of satiety that's similar to other saturated fats, MCT oils can also be used as an appetite suppressant.
Ingredients to avoid
Lots of products are marketed as "fat burners," but not all work by actually burning fat.
You should expect to see some bad apples and shady marketing practices in the weight loss industry. The sad truth is that many fat-burning ingredients are nothing more than massive marketing scams based on extremely poor science. These scams are built on layers of manipulative studies, exaggerations, and lies, with everyone profiting handily — except for you.
We do not recommend spending your hard-earned money any amount of serious money on any of the products below:
The fat-burning characteristics of raspberry ketones were found exclusively in studies involving rats given impossibly large doses (and even still, the fat loss was minimal).[4,7] Of course, that wasn't mentioned in most of the marketing materials. See our Raspberry Ketones page for more information.
Recent human studies on African mango have been entirely funded by supplement manufacturers. The positive results are possibly attributable to the fruit's very high fiber content, rather than any special weight-loss qualities. Our African mango page breaks down the studies in further detail.
This supplement showed some positive results in studies involving obese patients, but has yet to show any results in patients who are more normally overweight.
Conjugated linoleic acid (CLA)
CLA has been sold as a fat burner for over a decade, and the advertising pitch keeps shifting as claims are systematically debunked. It has been marketed for everything from "targeted fat burning" to "burning fat while you sleep." CLA has shown significant fat reduction in certain rat studies,[6,9] but so far, there are no human studies to substantiate these claims.
Acai berry was promoted on the Dr. Oz Show and The Oprah Winfrey Show, but when its health claims were debunked, the celebrities sued the supplement manufacturers that claimed they endorsed it! Acai berries have a significant amount of omega-3s, but so do a lot of foods. Acai berry has not yet been shown to do anything particular to promote weight loss or fat burning.
Avoid the scams
While there are some benefits to many of the products listed here, one of the biggest problems is the method in which they're marketed and sold.
If you really want to sample some of these products, the good news is that they aren't dangerous. Just make sure that you aren't signing up for any "free trials" that will burn you with a monthly subscription fee that you can't cancel — these scams can range anywhere from a few dollars to $60 per month or more. (Never give your credit card when you're getting a "free sample" or signing up for a "free trial." Free means free. When a website won't send you your sample until you give up your credit card number, you can expect to see a charge.)
Find a quality brand, such as NOW Foods, Jarrow Formulas, or AI Sports Nutrition, that won't charge you an arm and a leg. That way, if you don't see any weight loss results, you won't be out a small fortune.
A common side effect with any fat burner containing stimulants is a strong sensation of anxiousness, nervousness, and jitters. While this usually accompanies an energy spike that can help you get through a workout, some people find the sensation is too overwhelming and interferes with their ability to focus. Taking stimulants on an empty stomach can result in gastrointestinal distress, and diuretics cause water retention, which leads to heavy and frequent urination.
One issue that comes up often is the loss of muscle concurrently with (or instead of) fat. This typically happens when you overlook proper diet and regular exercise. Diet is by far the most important component in shedding fat, and establishing a regular workout regimen is much more important than taking a supplement. The right supplement can accelerate your fat loss, but only if your diet and fitness are where they need to be.
The FDA does not regulate fat burning supplements. They generally do not have a recommended daily allowance (RDA), except for the one set by the manufacturer. Always consult your healthcare provider before making changes to your diet, exercise, or supplementation routines.
Fat burners can interact negatively with some prescription and over-the-counter (OTC) medications. Be sure to consult with a doctor to verify possible contraindications.
Where to buy
You can find a wide variety of fat burning supplements, specifically products that are backed by solid science, here at PricePlow. Plus, you'll save 30% to 50% off of retail prices.
What we like
This is our favorite fat burner by far. It's got an open label so you can see the ingredients and dose. Further, its ingredient composition and dosing is designed to be flexible so the product can be used at a low dose by a 100-pound woman, or scaled up for a 300-pound bodybuilder. You can get more information about this product from our full length review.
ANS Performance's DIABLO is unique in that it's a fat-burning powder that you can drink. It combines the qualities of a thermogenic and a lipolytic with L-carnitine, caffeine anhydrous, and PEA for improved energy, mood, and focus.
On their own, Dexamine is a powerful lipolytic and ThyroTwin is a potent thermogenic. They're designed to be stacked for maximum effect, however, and they cover all the bases when they do: fat mobilization, a metabolism boost that lasts even when at rest, improved energy and focus, and suppression of unwanted food cravings.
A great choice for those who are stim-sensitive and want a lower-stim fat burner, ErgoGenix includes good ingredients at effective doses. What we love about this product is that each capsule has just 50mg of caffeine, so you can tailor the dosage to your liking.
By far the best stimulant-free fat burner on the market — whether you're taking it alone or stacking it with a stim-containing fat burner. Burn 24 relies on incredibly in-depth scientific research for all of its ingredients.
We always say there are no miracle fat burners. This is about as close as it gets with our current knowledge of how fat loss works.
- Hursel, R, et al; The American Journal of Clinical Nutrition; "Catechin- and caffeine-rich teas for control of body weight in humans;" December 2013
- Westerterp-Plantenga, MS, et al; Obesity Research; "Body weight and weight maintenance in relation to habitual caffeine intake and green tea;" July 2005
- Lejeune, Manuela, et al; British Journal of Nutrition; "Effect of Capsaicin on Substrate Oxidation and Weight Maintenance after Modest Body-weight Loss in Human Subjects;" 2003
- Morimoto, Chie, et al; Life Sciences; "Anti-obese action of raspberry ketone;" 2005
- Heymsfield, SB, et al; Journal of the American Medical Association; "Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial;" 1998
- West, D, et al; FASEB Journal; "Reduced body fat with conjugated linoleic acid feeding in the mouse;" 1997
- Gaunt, I.F., et. al; Food and Cosmetics Toxicology; "Acute and short-term toxicity of p-hydroxybenzyl acetone in rats;" 1970
- Egras, Amy, et. al; Journal of Obesity; "An Evidence-Based Review of Fat Modifying Supplemental Weight Loss Products;" 2011
- Kook, S, et. al; Intech "The Effect of CLA on Obesity of Rats:Meta-Analysis;" 2012
- Ulbricht, C, et. al; Journal of Dietary Supplements; "An evidence-based systematic review of acai (Euterpe oleracea) by the Natural Standard Research Collaboration;" June 2012