Yohimbe

Yohimbe is a rarity on natural foods store shelves: a traditional herb of Africa. It is derived from the inner bark of a large evergreen tree in the madder (Rubiaceae) family indigenous to the tropical forests of Cameroon, Gabon, and Zaire.

An alkaloid derived from yohimbe is used in conventional drugs for male impotence and yohimbe has become a prominent if controversial herb for promoting sexual desire and performance. Within the past decade various over-the-counter herbal preparations containing yohimbe have become increasingly popular, primarily as natural aphrodisiacs.

Do scientists know how it works?

Traditional Uses

Natives to West Africa have used yohimbe for centuries by making a bitter tea from bark shavings. Drinking the tea allowed warriors who were preparing for battle become more fearless and aggressive and have more stamina. Africans used yohimbe tea selectively to help promote love as well as war.

Male members of some tribes would take yohimbe as part of marriage and mating rituals and during special week-long fertility celebrations when sexual relations would be encouraged. Yohimbe gained a reputation for increasing libido as well as improving male sexual performance by enhancing the size and staying power of erections. Some tribes also used yohimbe to help treat such conditions as fever, high blood pressure, and coughs.

Modern Uses

Scientific studies on yohimbe conducted since the 1930s have confirmed that the herb has definite effects on aspects of sexual performance.

The alkaloid yohimbine isolated from yohimbe has become generally accepted by the medical establishment as an effective drug to treat some types of male impotence.

Yohimbe (though not the whole herb) has been the subject of at least two-dozen scientific studies, most of which have confirmed its ability to increase blood flow to the penis and cause "erectile stimulation."

Today yohimbine is approved by the FDA for treatment of male impotence, whether due to vascular problems, diabetes, or psychogenic causes. Even some veterinarians now turn to yohimbine to treat impotent breeding stallions, for example.

Studies have determined that yohimbine is useful for arousing animals (including horses, elk, cats, and dogs) and shortening their recovery after they have been sedated or anesthetized. A few studies have also explored yohimbine's potential in the treatment of narcolepsy (uncontrollable sleepiness) and congestive heart failure.

A growing category of use of the whole herb is in bodybuilding and weight-loss formulas, though only a few studies (again, done with yohimbine) have suggested potential benefits on thermogenesis (fat burning) and others have shown no effect on such factors as body weight, body fat, increase muscle and strength.

Some people take yohimbe as a stimulant or mood brightener. Yohimbe may also play a role in helping to treat or prevent exhaustion and mild depression.

In Weight Lifting - 90 percent of those who have try Yohimbe are happy with the results. Incredible gains in lean hard muscle mass with less body fat have been reported. Yohimbe is very effective in increasing the natural production of testosterone (male hormone).

High levels of testosterone can make the difference between strong, well-developed muscles and/or a flabby, smooth appearance. Not only does yohimbe help build muscle and strength, but recent research shows it may elevate your mood, slow down the aging process and boost your sex drive. Yohimbe causes less moodiness than Tribulus.

Recent findings

Researchers have found that yohimbine seems to influence the nervous system in a way that may boost the effects of Luvox and other serotonin-promoting drugs taken for depression and obsessive-compulsive disorder.

Depressed people who had not responded to Luvox showed significant improvement when yohimbe was added to their therapy.

A systematic review and meta-analysis of randomized clinical trials of yohimbine for erectile dysfunction concluded that the alkaloid is superior to placebo and that serious adverse reactions were infrequent and reversible.

The authors described yohimbine as "a reasonable therapeutic option for erectile dysfunction that should be considered as an initial pharmacologic intervention."

Researchers at Valparaiso University in Indiana found that yohimbine had more beneficial effects on most aspects of sexual response in men with erectile dysfunction than in sexually functional men, including an increase in the frequency of sexual activity and increased sexual arousal and erectile response during masturbation.

Do scientists know how it works?

Yohimbe contains a complex mixture of compounds including alkaloids as well as some tannins. Most of the herb's effects are thought to be due to yohimbine, although reserpinoid alkaloids and other chemicals found in the whole herb may modify yohimbine's effects.

Yohimbine works by blocking certain types of neurotransmitter-receptors in nerve cells. Yohimbine affects primarily a part of the adrenaline-related or "adrenergic" nervous system, which helps control aspects of various bodily functions, including motor activity and sexuality.

Yohimbine is thought to have a relatively minor effect on adrenaline, the hormone that stimulates the heart and temporarily increases muscular strength.

The alkaloid has a major impact, however, on blood levels of noradrenaline, a neurotransmitter secreted by certain nerve endings and by the adrenal gland. Noradrenaline levels affect blood pressure, sex drive, bodily metabolism, alertness, and other aspects of bodily function. Yohimbine stimulates the central nervous system, increases resting heart rate, and slightly raises body temperature.

It dilates small arteries in the skin and increases blood flow to peripheral parts of the body. In men this surge of arterial blood to the penis is accompanied by slight compression of veins there, thus preventing blood from flowing out of the organ.

Safety

Yohimbe may cause side effects similar to those of other stimulants, including anxiety, restlessness, jitters, dizziness, headache, and insomnia.

Higher doses may lead to more serious symptoms such as rapid heartbeat and a dramatic rise in blood pressure.

Those who should not use yohimbe include children, pregnant women, and the elderly; people with psychiatric conditions; anyone with a history of problems related to the heart, liver, or kidneys; and persons who have gastric or duodenal ulcers. Yohimbe should not be taken with mood-modifying drugs and antidepressants.

Other individuals who are not good candidates for experimenting with yohimbe include anyone prone to panic attacks, schizophrenia, or manic-depressive illness, and persons with diabetes or hypoglycemia.

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References

Cappiello, A., et al., "Yohimbine augmentation of fluvoxamine in refractory depression: A single-blind study," Biol Psychiatry (1995), 38:765-67

Ernst, E., and M.H. Pittler, "Yohimbine for erectile dysfunction: a systematic review and meta-analysis of randomized clinical trials," J Urol (1998), 159(2):433-36

Hollander, E., and A. McCarley, "Yohimbine treatment of sexual side effects induced by serotonin reuptake blockers," Journal of Clinical Psychiatry (1992), 53(6): 207-09

Mann, K., et al., "Effects of yohimbine on sexual experiences and nocturnal penile tumescence and rigidity in erectile dysfunction," Archives of Sexual Behavior (1996), 25:1-16

Rowland, D.L., "Yohimbine, erectile capacity, and sexual response in men," Arch Sex Behav (1997), 26(1):49-62

Susset, J.G., et al., "Effect of yohimbine hydrochloride on erectile impotence: A double-blind study," Journal of Urology (1989), 141(6):1360-63