Although several trials have investigated the efficacy of Garcina Cambogia (GC) for both body weight and fat loss in humans, most have been conducted on small sample sizes (less than 20) and for less than 12 weeks’ duration. The majority found no significant effects.

One of the largest and better quality trials was conducted in 1998 on 135 subjects with an average BMI of 32 kg/m2 by Heymsfield et al. Sixty-six patients received GC standardized to 1500 mg of hydroxycitric acid per day, while 69 received placebo (a nonactive pill). The experiment was blinded, meaning both groups were unaware of whether or not they were receiving GC. Interestingly, both groups lost a significant amount of weight over the 12-week treatment period; however, there was no difference in weight loss or body fat mass loss between the people taking GC and the people taking placebo.

This finding was in agreement with a 2011 summary by Onakpoya et al of all available trials at the time that concluded that GC extract possessed limited or no effects on weight-loss in human subjects. An even more recent analysis in 2015 by Fassina et al also supported this conclusion.

Claims by companies selling GC extracts for weight loss seem to be based on either animal studies or laboratory investigations into the effects of hydroxycitric acid (HCA) the main active ingredient of GC. While it is true that in a laboratory dish, HCA does inhibit an enzyme called citrate lyase, thereby interfering with fat metabolism, it is a big leap to then say that this translates to weight loss in humans.

Evidence so far does not support using GC as a weight loss supplement, although a larger scale, longer duration trial is needed. For people trying to lose weight, increasing their activity level and eating a healthier diet with more vegetables, whole grains, and less red meat is probably more effective than taking GC supplements.

Sources

• Heymsfield SB, Allison DB, Vasselli JR, et al. Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial. JAMA. 1998 Nov 11;280(18):1596-600.
• Fassina P, Scherer Adami F, Terezinha Zani V, et al. The effect of garcinia cambogia as coadjuvant in the weight loss process. Nutr Hosp. 2015 Dec 1;32(6):2400-8. doi: 10.3305/nh.2015.32.6.9587.
• Onakpoya I, Hung SK, Perry R, Wider B, Ernst E. The use of Garcinia extract (Hydroxycitric Acid) as a weight loss supplement: a systematic review and meta-analysis of randomized clinical trials. Journal of Obesity. 2011;2011:9 pages.509038
• Chuah LO, Ho WY, Beh BK, Yeap SK. Updates on Antiobesity Effect of Garcinia Origin (−)-HCA. Evidence-based Complementary and Alternative Medicine : eCAM. 2013;2013:751658. doi:10.1155/2013/751658.