Yohimbine is an indole alkaloid extracted from the bark of very tall evergreen tree, Pausinystalia yohimbe from Central Africa. It is found in sport supplement products as well as in veterinary drugs for what is called reverse sedating dogs and deer.

Extracts of yohimbe are also marketed as dietary supplements for correcting erectile dysfunction and improving sexual performance. The extracts have been used in traditional medicine for many years. In 1998, an extensive review of the clinical studies where the alkaloid had been used recommended the drug be offered as a pharmacological intervention (Ernst and Pittler, 1998).

Yohimbine has been used as a weight loss and dieting supplement. The evidence is inconclusive and there are too many side effects to consider it a viable option for this purpose. It is an α-2 receptor antagonist. These particular receptors are found in tissues where fat uptake and use is common. Some studies suggested it speeds up lipid metabolism (Galitsky et al., 1988; Lafontan et al., 1992).

Up to 2004, there were three double-blind RCTs which were considered suitable for analysis of the effects of yohimbine in weight loss studies (Berlin et al., 1986; Kucio et al., 1991; Sax, 1991). In these, the patients were overweight by at least 15% or had a BMI of between 28 and 48. The research was inconclusive and thought not to be significant (Pittler and Ernst, 2004). Fortunately, there were no adverse effects.

The alkaloid is often found with other supplements and there is another suggestion that its ineffectiveness may be because of the effects of other ingredients countering its benefits. It is also metabolised very rapidly which may undo some of its positive attributes.

Toxicity

Nausea, vomiting and abdominal pain have been described but liver toxicity has not been noticed.

References

Berlan, M., Le Verge, R., Galitzky, J., Le Corre, P. (1993) α2-adrenoceptor antagonist potencies of two hydroxylated metabolites of yohimbine. Br. J. Pharmacol. 108: pp. 927-932.

Berlin I, Stalla-Bourdillon A, Thuillier Y, Turpin G, Puech J. (1986) Lack of efficacity of yohimbine in the treatment of obesity. J Pharmacol. (Paris) 17: pp. 343–7.

Ernst, E., & Pittler, M. H. (1998). Yohimbine for erectile dysfunction: a systematic review and meta-analysis of randomized clinical trials. The Journal of Urology, 159(2), pp. 433-436. https://doi.org/10.1016/S0022-5347(01)63942-9

Galitzky, J., Taouis, M., Berlan, M., Riviere, D., Garrigues, M., Lafontan, M. (1988) Alpha 2-antagonist compounds and lipid mobilization: evidence for a lipid mobilizing effect of oral yohimbine in healthy male volunteers. Eur. J. Clin. Invest. 18: pp. 587-594. 10.1111/j.1365-2362.1988.tb01272.x.

Kucio, C., Jonderko, K., Piskorska, D. (1991) Does yohimbine act as a slimming drug? Isr. J. Med. Sci. 27 pp. 550–6

Lafontan, M., Berlan, M., Galitzky, J., Montastruc, J.L. (1992) Alpha-2 adrenoceptors in lipolysis: alpha 2 antagonists and lipid-mobilizing strategies. Am. J. Clin. Nutr. 55 (1 Suppl): 219S-227S.

Pittler, M. H., & Ernst, E. (2004). Dietary supplements for body-weight reduction: a systematic review. The American Journal of Clinical Nutrition, 79(4), pp. 529-536.

Sax, L. (1991) Yohimbine does not affect fat distribution in men. Int. J. Obes. 15 pp. 561–5