Yohimbine

Yohimbine is a naturally occurring indole alkaloid, structurally a cyclized tryptamine derivative, obtained principally from the bark of the yohimbe tree, Pausinystalia johimbe, an evergreen native to central and western Africa; related alkaloids occur in Rauwolfia and in the South American tree Aspidosperma quebracho-blanco ^[1]. In whole yohimbe bark, yohimbine is only one of many indole alkaloids present and makes up a minor fraction of the total, which is one reason herbal preparations vary so much in strength ^[1][4].

The compound has a long ethnobotanical history as an aphrodisiac in West Africa, and purified yohimbine was marketed in Europe from around the turn of the twentieth century ^[1]. Its best-studied medical use is for erectile dysfunction; a meta-analysis of randomized, placebo-controlled trials concluded that yohimbine used on its own was more effective than placebo and that serious adverse reactions were infrequent, although the evidence predates modern PDE5 inhibitor drugs ^[3]. Yohimbine is also used in veterinary medicine to reverse the sedative xylazine, and it serves as a research tool to provoke anxiety and to probe noradrenergic systems ^[1].

Regulatory treatment of yohimbine is inconsistent. In the United States, yohimbine hydrochloride has a history as an approved prescription medicine, while yohimbe bark extracts are also sold in dietary supplements; regulators have warned that marketing supplements with drug claims is not permitted ^[1]. Several countries restrict or ban yohimbe in supplements ^[1]. Analyses of the US supplement market have found that labeled yohimbine content is frequently inaccurate and that some products contain pharmaceutical-level quantities, which complicates safe use ^[4]. Reported adverse effects include elevated blood pressure, rapid heartbeat, anxiety, tremor, and, at high doses or with drug interactions, more serious cardiovascular events ^[1].

This one has a real side-effect profile: anxiety, panic, tremor, elevated heart rate and blood pressure, and sweating. It can be dangerous for people with hypertension, heart conditions, or anxiety disorders, and it interacts with MAOIs, stimulants, and many antidepressants. Start low and avoid late-day dosing.

Yohimbine is an alpha-2 adrenergic antagonist that raises central and peripheral noradrenergic tone, so its most established concern is combination with monoamine oxidase inhibitors; MAOIs plus yohimbine can provoke hypertensive and sympathetic overstimulation and this pairing is classically contraindicated. It antagonizes the blood-pressure-lowering effect of clonidine and other alpha-2 agonists and can blunt or oppose antihypertensive therapy generally. Case reports and pharmacology reviews describe additive pressor and anxiogenic effects when yohimbine is combined with tricyclic antidepressants, sympathomimetic stimulants, and other agents that increase noradrenergic signaling. Concurrent use with serotonergic or stimulant drugs has been associated with anxiety, tachycardia, and elevated blood pressure. This is research information, not medical advice.

Checking a whole stack? Run it through interactions + stacks.

Yohimbine is an indole alkaloid isolated from the bark of the West African tree Pausinystalia johimbe, whose bark had a long folk reputation as an aphrodisiac before Western chemists took interest. The pure alkaloid was isolated in the closing years of the nineteenth century, with Leopold Spiegel commonly credited for characterizing it around 1896. In twentieth-century medicine it was used as an alpha-2 adrenergic antagonist and reached the United States as the prescription product Yocon for erectile dysfunction, an indication later eclipsed by PDE5 inhibitors. Today yohimbine and crude yohimbe bark extracts circulate mostly as over-the-counter and grey-market supplements marketed for fat loss and libido rather than as a mainstream prescription drug.