Do Fat Burners Work?

The world has more than one billion overweight adults. No wonder we’re bombarded with messages pushing “fat burners” – supplements that supposedly help you get lean by popping a pill. 

Some manufacturers even promise that taking their supplement will allow you to indulge in all your favourite foods and still display a slim, eye-catching figure. But do fat burners really get the job done? Let’s find out!

Do Fat Burners Work?

There are lots of fat burners on the market. The usual claims are that they work in one or more of the following ways: by raising metabolism, suppressing appetite, or increasing fat oxidation. That last one means you burn more fat for fuel.

All of this sounds good on paper. Unfortunately, most fat burners don’t help you lose anything (except your hard-earned cash). The following are just five of the many fat burners that don’t work. Avoid them!


This is an amino acid that plays a crucial role in transporting fatty acids into your cells’ mitochondria ─ the place where fat can be burned for energy. That’s why L-Carnitine is often believed to aid fat loss. 

Unfortunately, L-Carnitine doesn’t work. One double-blind study supplemented 18 moderately overweight women with two grams of L-Carnitine twice a day for eight weeks in combination with an aerobic exercise programme.

At the end of the trial, there was no difference in weight and fat loss between those who received the supplement and those given a placebo [1]. 

CLA (conjugated linoleic acid)

CLA is a mixture of polyunsaturated fatty acids naturally found in meat and milk. It is also available in supplement form. CLA is believed to promote fat loss by activating PPARa receptors, inhibiting PRARy receptors, and increasing metabolism.

The truth? One double-blind study published in American Journal of Clinical Nutrition supplemented 122 moderately obese but otherwise healthy subjects with 3.4 grams a day for one year [2].

When the study was over, “no significant difference in body weight or body fat regain was observed between the treatments,” the report said. Since the publication of those findings, five other studies came to the same conclusion: CLA is a useless fat burner [3-7]. 

Garcinia Cambogia

After being labelled a “revolutionary fat buster” by Dr Oz, bottles containing extracts of this pumpkin-shaped fruit began selling like hot cakes. The claims were that Garcinia Cambogia gets you lean by inhibiting citric acid lyase – an enzyme that aids in fat storage. 

Unfortunately, Garcinia Cambogia doesn’t work, as shown by a placebo-controlled study published in Nutrition Journal. The research, which involved 86 subjects, found that supplementation with two grams of Garcinia Cambogia daily for ten weeks failed to promote weight loss [8].

Another study even found that those given a placebo lost more weight than subjects who took hydroxycitric acid, which is Garcinia Cambogia’s active ingredient [9].

Raspberry Ketones

Raspberry ketones are natural substances found in various fruits, including cranberries, blackberries, raspberries, and kiwis. Those found in supplements, however, are synthetically derived. 

Raspberry ketones allegedly help you shed fat by increasing norepinephrine sensitivity. (Norepinephrine is a catecholamine that aids fat burning.) And while that is an often-heard claim, there’s no evidence whatsoever showing raspberry ketones to boost fat loss. 

Only one study found that rats gained less weight on a high-fat diet when they received raspberry ketones [10]. The problem? This doesn’t prove it helps you lose fat. It was done on rats. And to get a similar dose to that used in the study, you need to consume 100 times the recommended dosage!


The South African desert plant called Hoodia Gordonii is used to suppress thirst and appetite. Its selling point are claims that it reduces your calorie intake and thus helps you get slim.

The truth? Research showed that 15 days of Hoodia supplementation in overweight women had no more benefits for energy intake or body weight than a placebo [11]. 

The above are just a few of the useless fat burners.

There are many more pills, powders, potions, and other concoctions that don’t burn fat. Ironic, right? But here’s the good news:

Some Supplements Do Aid Fat Loss

Fortunately, not all fat-burning supplements are a scam. There are a few scientifically proven to work. We’re going to look at them in a second, but before doing so, let’s make one thing crystal clear: 

No pill, powder, or potion will rid you of excess flab and magically give you a cover model silhouette. 

The key to losing fat will always be proper nutrition, working out properly, and enough rest and recovery! That said, here are three proven fat burners that can help.


Yes, it’s true: your favourite cup of java can help you slim down. It promotes fat loss in three ways [12-16].

  1. Caffeine raises your metabolic rate. It does so by elevating epinephrine levels.
  2. Caffeine increases fat oxidation. It means your body will use more fat for fuel. This is also due to higher epinephrine levels.
  3. Caffeine blunts appetite. It makes it easier to keep calorie intake under control. Those appetite-reducing effects, however, seem to apply only to men.

Important to note is that the fat loss benefits of caffeine only work if you haven’t built up a tolerance to the compound. That’s why, if you consume caffeine daily, it aids weight loss in the short-term. But once the tolerance kicks in, the fat loss benefits disappear [17-19]. 

So, if you want to use caffeine as a fat burner, it’s important to cycle the compound. You do so by limiting caffeine consumption to no more than two days per week.

If you’re tolerant to caffeine (which you are if caffeine doesn’t give you a buzz anymore), then two weeks without it should be enough to reverse the tolerance. (If you have only a slight tolerance, you might need less time. A strong tolerance might take longer to reverse.) 

Caffeine is best used as a fat burner before your workouts. You can take this either in supplement form or by drinking caffeinated beverages such as coffee. Consume between 200mg and 300mg to get the fat-burning benefits.

Protein Powder

Protein is the most satiating macronutrient. So much so that when people add an extra bit to their diet, they automatically consume fewer calories [20]. That’s why a high-protein diet aid fat loss. 

The reason protein is so satiating is because it raises satiety hormones such as GLP-1, Peptide YY, and cholecystokinin while suppressing the hunger hormone ghrelin [21-24]. 

That’s where the strength of protein powder lies. Since it contains only a small amount of carbs and fat, it gives you a lot of protein but only a tiny number of calories. It’s why adding protein powder can stimulate fat loss [25-26].


Certain nutrient deficiencies slow down your metabolic rate, increase hunger, and decrease fat oxidation. Examples are zinc, vitamin D, and calcium deficiencies [27-30].  

That’s why covering all your nutritional bases can aid fat loss. This is ideally done through diet, but since most people can’t achieve it, a multivitamin can provide the solution.

A research report published in International Journal of Obesity tested the effects of a multivitamin on obese women [31]. Over six months, 96 obese Chinese women were divided into three groups. Group one received a placebo, group two a calcium supplement (162 mg), and group three a multivitamin.

After 26 weeks, the placebo group saw no changes in their body composition. The calcium group lost 0.9 kg of body weight plus 0.8 kg of body fat and slightly decreased their BMI and waist circumference. 

And those who received a multivitamin? They lost on average 3.6 kg of body weight, lowered their BMI by 1.4, reduced their waist circumference by 2.4 cm, and dropped 2.8 kg of fat!

The Bottom Line on Fat Burners

The market abounds in fat burners. Unfortunately, most don’t do anything besides parting you from your hard-earned money. 

Examples of worthless (but popular) fat burners are conjugated linoleic acid (CLA), Garcinia Cambogia, raspberry ketones, L-carnitine, green coffee extract, Hoodia, and white kidney bean. 

There are, however, three supplements that can improve fat loss (that is, if you combine them with a proper nutrition and exercise plan). Those are caffeine, protein powder, and a multivitamin.

I know, those supplements don’t sound fancy, and you shouldn’t expect them to perform miracles. However, they can nudge you towards achieving your ideal figure.


1. Villani, R. G., Gannon, J., Self, M., & Rich, P. A. (2000). L-Carnitine supplementation combined with aerobic training does not promote weight loss in moderately obese women. International Journal of Sport Nutrition and Exercise Metabolism, 10(2), 199-207.

2. Larsen, T. M., Toubro, S., Gudmundsen, O., & Astrup, A. (2006). Conjugated linoleic acid supplementation for 1 y does not prevent weight or body fat regain. American Journal of Clinical Nutrition, 83(3), 606-12.

3. Joseph, S. V., Jacques, H., Plourde, M., Mitchell, P. L., McLeod, R. S., & Jones, P. J. (2011). Conjugated linoleic acid supplementation for 8 weeks does not affect body composition, lipid profile, or safety biomarkers in overweight, hyperlipidemic men. Journal of Nutrition, 141(7), 1286-91.

4. Venkatramanan, S., Joseph, S. V., Chouinard, P. Y., Jacques, H., Farnworth, E. R., & Jones, P. J. (2010). Milk enriched with conjugated linoleic acid fails to alter blood lipids or body composition in moderately overweight, borderline hyperlipidemic individuals. The Journal of the American College of Nutrition, 29(2), 152-9.

5. Nazare, J. A., De la Perriere, A. B., Bonnet, F., Desage, M., Peyrat, J., Maitrepierre, C., . . . Laville, M. (2007). Daily intake of conjugated linoleic acid-enriched yoghurts: effects on energy metabolism and adipose tissue gene expression in healthy subjects. British Journal of Nutrition, 97(2), 273-80.

6. Syvertsen, C., Halse, J., Hoivik, H. O., Gaullier, J. M., Nurminiemi, M., Kristiansen, K., . . . Gudmundsen, O. (2007). The effect of 6 months supplementation with conjugated linoleic acid on insulin resistance in overweight and obese. International Journal of Obesity, 31(7), 1148-54.

7. Diaz, M. L., Watkins, B. A., Anderson, R. A., & Campbell, W. W. (2008). Chromium picolinate and conjugated linoleic acid do not synergistically influence diet- and exercise-induced changes in body composition and health indexes in overweight women. The Journal of Nutritional Biochemistry, 19(1), 61-8.

8. Kim, J. E., Jeon, S. M., Park, K. H., Lee, W. S., Jeong, T. S., McGregor, R. A., & Choi, M. S. (2011). Does Glycine max leaves or Garcinia Cambogia promote weight-loss or lower plasma cholesterol in overweight individuals: a randomized control trial. Nutrition Journal, 10, 94.

9. Heymsfield, S. B., Allison, D. B., Vasselli, J. R., Pietrobelli, A., Greenfield, D., & Nunez, C. (1998). Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial. The JAMA Network, 280(18), 1596-600.

10. Morimoto, C., Satoh, Y., Hara, M., Inoue, S., Tsujita, T., & Okuda, H. (2005). Anti-obese action of raspberry ketone. Life Science, 77(2), 194-204.

11. Blom, W. A., Abrahamse, S. L., Bradford, R., Duchateau, G. S., Theis, W., Orsi, A., . . . Mela, D. J. (2011). Effects of 15-d repeated consumption of Hoodia gordonii purified extract on safety, ad libitum energy intake, and body weight in healthy, overweight women: a randomized controlled trial. American Journal of Clinical Nutrition, 94(5), 1171-81.

12. Acheson KJ. (1980). Caffeine and coffee: their influence on metabolic rate and substrate utilization in normal weight and obese individuals. American Journal of Clinical Nutrition, 33(5):989-97.

13. Norager, C. B., Jensen, M. B., Weimann, A., & Madsen, M. R. (2006). Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study. Clinical Endocrinology, 65(2), 223-8.

14. Astrup, A., Toubro, S., Cannon, S., Hein, P., Breum, L., & Madsen, J. (1990). Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers. American Journal of Clinical Nutrition, 51(5), 759-67.

15. Keijzers, G. B., De Galan, B. E., Tack, C. J., & Smits, P. (2002). Caffeine can decrease insulin sensitivity in humans. Diabetes Care, 25(2), 364-9.

16. Tremblay, A., Masson, E., Leduc, S., Houde, A., & Despres, J. (1988). Caffeine reduces spontaneous energy intake in men but not in women. Nutrition Research, 8(5), 553-558.

17. Astrup, A., Breum, L., Toubro, S., Hein, P., & Quaade, F. (1992). The effect and safety of an ephedrine/caffeine compound compared to ephedrine, caffeine and placebo in obese subjects on an energy restricted diet. A double blind trial. International Journal of Obesity and Related Metabolic Disorders, 16(4), 269-77.

18. Pasman, W. J., Westerterp-Plantenga, M. S., & Saris, W. H. (1997). The effectiveness of long-term supplementation of carbohydrate, chromium, fibre and caffeine on weight maintenance. International Journal of Obesity and Related Metabolic Disorders, 21(12), 1143-51.

19. Westerterp-Plantenga, M. S., Lejeune, M. P., & Kovacs, E. M. (2005). Body weight loss and weight maintenance in relation to habitual caffeine intake and green tea supplementation. Obesity Research, 13(7), 1195-204.

27. Maxwell, C., & Volpe, S. L. (2007). Effect of zinc supplementation on thyroid hormone function. A case study of two college females. Annals of Nutrition and Metabolism, 51(2), 188-94.

28. Jacobsen, R., Lorenen, J. K., Toubro, S., Krog-Mikkelsen, I., & Astrup, A. (2005). Effect of short-term high dietary calcium intake on 24-h energy expenditure, fat oxidation, and fecal fat excretion. International Journal of Obesity, 29(3), 292-301.

29. Foss, Y. J. (2009). Vitamin D deficiency is the cause of common obesity. Medical Hypotheses, 72(3), 314-21. 

30. Vigna L et al. T8:PO.110. European Congress on Obesity; May 6-9, 2015; Prague, Czech Republic.

31. Li, Y., Wang, C., Zhu, K., Feng, R. N., & Sun, C. H. (2010). Effects of multivitamin and mineral supplementation on adiposity, energy expenditure and lipid profiles in obese Chinese women. International Journal of Obesity, 34(6), 1070-7. 

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