|Yohimbine is an alkaloid contained in the bark of an African tree, yohimbe. The yohimbe tree is found growing in the wild throughout tropical west Africa from Nigeria to Gabon along the coast. It is a tall evergreen with large, leathery leaves. Because yohimbine is
the most active component of yohimbe, the two names are often used interchangeably. Other minor alkaloids found in yohimbe bark include ajmaline, alloyohimbine, corynanthine, quebrachine and tetrahydromethylcorynanthein.
Yohimbine is a monoamine oxidase inhibitor that stimulates increase norepinephrine release. Yohimbine blocks alpha-2 adrenergic receptors, part of the sympathetic nervous system. Yohimbine is a monoamine oxidase (MAO) inhibitor to increase levels of the neurotransmitter, norepinephrine. Yohimbine also acts as a central nervous system stimulator and may increase energy levels and promote fat oxidation. It also dilates blood vessels and is useful in the treatment for erectile dysfunction and some forms of impotence in men. Yohimbine has also been used for weight loss. In summary, yohimbine may have some mahor benefits, including increased serum testosterone levels, muscle growth and strength, weight loss, fatigue and sexual function.
Possible side effects may include dizziness, nausea, insomnia, anxiety, increased blood pressure, and rapid heart beat. Higher doses of oral yohimbine create numerous side effects such as salivation, dilated pupils, emptying of the bowels, low blood pressure, and irregular heartbeat ending in heart failure. Patients with kidney disease, peptic ulcer or pregnant or breast-feeding women should not use yohimbe. Drugs such as phenothiazines enhance yohimbine toxicity. Yohimbine is contraindicated in individuals with high or low blood pressure, bipolar disorder, existing liver and kidney disease, or patients who are pregnant or on tricyclic antidepressants.