Yohimbe is an herbal or natural supplement extracted from the bark of the African tree pausinystalia yohimbe, which contains yohimbine, the active ingredient. In most dietary supplements, yohimbe is standardized to 3% yohimbine. Yohimbine is an alpha2-antagonist Human fat cells possess both alpha- and beta-adrenergic receptors. Catecholamines are able to stimulate lipolysis through beta-receptors, whereas they inhibit lipolysis through alpha2-receptors. The balance between these receptors controls the rate of lipolysis. Therefore, an increase in thermogenesis for fat-loss purposes could be achieved by either stimulating beta­receptors or by blocking alpha2-receptors. Because yohimbine has alphaTantagonistic properties, this supplement could be used during fat-loss procedures to further increase the rate of lipolysis. This discussion will focus on the lipolytic effect of yohimbine. However, it should be noted that yohimbine is a prescription drug. No specific studies have been done on yohimbe.

Animal Studies

Oral or intravenous administration of yohimbine in dogs has resulted in a significant elevation in plasma free fatty acids and an increase in sympathetic nervous system activity. Norepinephrine was significantly elevated following yohimbine administration. Furthermore, chronic oral administration resulted in a reduction in body weight and in food intake, suggesting that alpha2­antagonists may influence satiety. The lipolytic effect of yohimbine may result either from a direct action of yohimbine or from an activation of the sympathetic nervous system.

Human Studies

The interplay of beta-receptors and alphaTreceptors regulates the lipolytic response of adipose tissue to the catecholamines. A supplement which would inhibit the alpha2-receptors would theoretically increase the action of catecholamines on lipolysis. Yohimbine has been shown to effectively increase lipolysis.

An abundance of studies have been done investigating the lipolytic action of yohimbine in humans. In vitro studies using human adipocytes have indicated stimulatory effects of yohimbine on lipolysis when catecholamines are present.

Oral administration of yohimbine to humans has been shown to significantly elevate plasma glycerol and free­fatty acids. Furthermore, the effect of yohimbine was further enhanced during physical exercise when the levels of catecholamines are further elevated. Yohimbine also appears to stimulate norepinephrine levels by increasing sympathetic nerve activity.

When yohimbine was administered during a low­energy diet, patients lost significantly more weight than patients receiving a placebo Energy expenditure did not decline in the patients consuming yohimbine, while the placebo group experienced a 15% reduction in energy expenditure.

Safety and Toxicity

Alpharreceptors are present in a number of tissues including heart, arteries, lung, and adipose tissue. Therefore, yohimbine could react with any of these receptors and influence those tissues. However, both animal and human studies indicate that cardiovascular changes are either nonexistent or minimal following yohimbine administration.

Some side effects associated with yohimbine include feelings of panic, clumsiness, and confusion. There have also been reports of chills, nausea, and tremors. The prescription form of yohimbine is normally prescribed for impotence problems; therefore, individuals may experience heightened sexual arousal. Furthermore, there have been reports of mood disturbances and anxiety.

Another concern regarding yohimbe is the purity of the dietary supplement. Yohimbine is the major alkaloid of the plant and the active ingredient. The bark of the tree has been reported to contain 6% total alkaloids, 10-15% of which are yohimbine. Most dietary supplements have been standardized to 3% yohimbine. Therefore, a 100-mg dose of yohimbe will contain only 3 mg of yohimbine. In research studies, yohimbine is usually administered at a dose of about 0.2 mg/kg of body weight.


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