Yohimbe Bark & Fertility

Yohimbe is a traditional West African aphrodisiac and treatment for sexual debility. While the bark has been used for centuries, it was not until 1938 that the alkaloid yohimbine HCl was isolated as its primary pharmacologically active constituent. Although yohimbine is responsible for most of the effects of the plant, there are over 30 other alkaloids in the bark, many of which are central nervous system stimulants, sedatives and tranquilizers. It is yohimbe's effects on male genital erection and CNS stimulant effects that have led to the mistaken conviction that yohimbe affects testosterone levels and semen production. As yohimbe can cause serious side effects, particularly when combined with other drugs, it is important to talk with your doctor before taking yohimbe.

Pharmacodynamics

Yohimbine HCl is a presynaptic α2-adrenergic receptor antagonist. It has a high degree of lipid permeability, causing central nervous system stimulation as soon as 20 minutes after ingestion. This stimulation is produced by increasing the levels of the body's own stimulating compound noradrenaline in the bloodstream. Paradoxically, yohimbine HCl simultaneously promotes parasympathetic nervous system activity, which is required for the erection of genital tissue. Yohimbine HCl also increases nitric oxide levels in the blood and acts as a Ca2+ channel blockers, displacing blood into cavernous body tissues.

Other Active Ingredients

While yohimbine HCl is the most potent of yohimbe's pharmacologically active constituents, it is likely that some of the other alkaloids contribute to its effects. Corynantheine and dicorynantheine in particular may act as sedatives and tranquilizers. Ajmaline may also exert a sedative effect, promoting the parasympathetic nervous system activity needed for the erection of male genital tissue. Despite these effects on male sexual performance, there is no evidence that yohimbe has a positive or negative impact on male fertility.

Side-Effects

Yohimbine may cause increased genital sensitivity and reflex excitability by stimulating nerves in the sacral region. This can dramatically reduce the time needed to reach orgasm. Nerve stimulation in the sacral region may also produce feelings of pins-and-needles, shivers, or tingling in the spine and lower back. Headache, high blood pressure, anxiety, loss of appetite, insomnia, and elevated heart rate are all common side-effects. Due to its blood pressure elevating properties, do not use yohimbe if you suffer from hypertension, heart disease, or kidney disease.

Drug Interactions

Although MayoClinic.com lists yohimbine HCl as a specific for psychogenic erectile dysfunction, it is known to interact with several antidepressant medication. In particular, yohimbe should not be combined with tricyclic or monoamine oxidase inhibiting antidepressants. According to Memorial Sloan-Kettering Cancer Center, this combination may cause a potentially fatal hypertensive crisis. Yohimbe's CNS stimulating activity may prove toxic when combined with other stimulants. MayoClinic.com lists bupropion and methamphetamine as stimulants known to produce dangerous side effects such as elevated heart rate and high blood pressure.