Yohimbine hydrochloride is the principal alkaloid of the bark of the African yohimbe tree, a member of the Rubiaceae family, which is a tall evergreen tree with grey-brown bark and leaves that are oblong and elliptical, and has been traditionally used to for medicinal purpose. This tree is found in African nations of Congo, Cameroon etc.
When given orally, yohimbine reaches peak levels in 10 – 15min, and the half-life is app. 30min.
Dried bark from the twigs and stalk of the yohimbe tree are used in their entirety, cut up or ground into powder to use as a drug. A variety of yohimbe bark extracts are offered as mono-preparations or combined with other substances in liquid, powder, capsule or tablet form. The quantities of yohimbine in these products vary. Its therapeutic use to treat sexual dysfunction, as an aphrodisiac and for fatigue and exhaustion. But most of the studies have failed to prove any of these effects.
Yohimbine hydrochloride is a Food and Drug Administration (FDA) approved prescription drug for the treatment of impotence.
Acc. to a 1984 study in the journal Science, by J.T. Clark & team ), Yohimbine extracts are used to treat impotence, a disorder that occurs in 1.2 to 2 percent of the male population. Yohimbine has also been used extensively in veterinary medicine for treatment of impotent breeding stallions.
In a 1987 study in the journal Lancet, a Canadian research team, led by K. Reid, 48 subjects with impotence took part in a 10 week trial of yohimbine (18mg/day) for restoring erectile function. Overall 46% of those who received yohimbine reported a positive response to the drug. Thus, Yohimbine was assumed to be a safe treatment for impotence that seems to be as effective as sex and marital therapy for restoring satisfactory sexual functioning.
In a 1997 study in the International Journal of Impotence Research, a German research team, led by H.J. Vogt , tested the effect of yohimbine hydrochloride on 86 patients with erectile dysfunction. Yohimbine was administered orally in a dosage of 30mg/day (two 5mg tablets three times daily) for eight weeks. Efficacy evaluation was based on both subjective and objective criteria. Subjective criteria included improvement in sexual desire, sexual satisfaction, frequency of sexual contacts, and quality of erection (penile rigidity) during sexual contact/intercourse. Objective criteria of outcome were based on improvement in penile rigidity. Yohimbine was found significantly more effective than placebo in terms of response rate. Yohimbine was well-tolerated: Only 7% of patients rated tolerability fair or poor, and most adverse experiences were mild. There was no serious adverse event.
Acc. to the 2000 study in the International Journal of Impotence Research, by Canadian researcher A. Morales, found that, Yohimbine blocks alpha-1 and alpha-2 adrenoceptors, increasing adrenaline and dopamine and decreasing serotonin levels. Blocking these receptors also increases blood pressure, releases insulin, and decreases blood sugar levels. Acc. to examine.com, “Yohimbine works by increasing adrenaline levels in the body, as well as inhibiting a regulatory process in fat cells, which normally suppresses fat burning.”
Just like ephedra, yohimbine also has side effects like excitation, insomnia, fear, hypertension, tachycardia, nausea and vomiting. This is because yohimbine is also a Central Nervous system stimulant, and it leads to elevation in blood pressure and heart rate, increased motor activity, irritability and tremors.
Authors Kowalchik & Hylton in their 1987 Rodale’s Illustrated Encylcopedia of Herbs, suggested that, a number of precautions have been suggested regarding the use of yohimbine. It should never be taken at the same time as foods or substances containing the amino acid tyramine. Liver, cheese, and red wine are rich in tyramine, as are certain diet aids and decongestants. Yohimbine is contraindicated for anyone with hypotension; diabetes; heart, liver, or kidney disease, and nervous disorders, especially schizophrenia.
Large doses of yohimbine can be toxic. A 2009 study in the journal Clinical Toxicology, by an Italian research team led by Andrea Giampreti , found that; yohimbine is currently approved in the United States for erectile dysfunction and has undergone resurgence in street use as an aphrodisiac and mild hallucinogen. In recent years yohimbine use has become common in body-building communities for its presumed lipolytic and sympathomimetic effects. The researchers described a 37-year-old bodybuilder in whom severe acute neurotoxic effects occurred 2h after yohimbine ingestion. The patient suffered from malaise, vomiting, loss of consciousness, and repeated seizures after ingestion of 5g of yohimbine during a body-building competition in a gymnasium.
A 2011 study in the Journal of Dietary Supplements, Canadian researchers Nevio Cimolai & Tomas Cimolai , suggested that, “In excess doses, it may typically cause agitation, anxiety, hypertension, and tachycardia. There is no conclusive evidence for this drug to be of benefit in bodybuilding, exercise tolerance, physical performance, or desirable alterations of body mass. Although tolerated generally well in low doses, the potential for dose-dependent toxicity should be recognized.”
In an earlier 1985 study in the journal Annals of Emergency Medicine, US researcher Dr. Christopher H. Linden & team, found that, following the ingestion of an alleged aphrodisiac known as “yo-yo,” a 16-year-old girl experienced an acute dissociative reaction accompanied by weakness, paresthesias, and in coordination. Subsequent symptoms included anxiety, headache, nausea, palpitations, and chest pain. Hypertension, tachycardia, tremors, and an erythematous rash were noted on physical examination. Serum epinephrine and norepinephrine levels were found to be elevated. Symptoms resolved spontaneously but lasted approximately 36 hours. The ingested substance was identified as yohimbine.
A 1997 study in the journal Urology, by a research team led by P. Kunelius , determined the effectiveness and safety of yohimbine for treatment of patients with mixed-type impotence. Twenty-nine patients received either a placebo or yohimbine hydrochloride (36mg/day orally). The treatment consisted of two 25 day courses; after a 14-day washout period, the patients who initially received the placebo for 25 days were switched to yohimbine hydrochloride for 25 days. Erectile function, ejaculation, interest in sex, physical examination findings, blood pressure, pulse rate, weight, and audio-visual sexual stimulation test were investigated before treatment and at the end of each drug period. Twenty-seven patients (93%) completed the entire schedule. Positive clinical results were obtained in 12 cases (44%) at the end of the yohimbine phase and in 13 (48%) after the placebo period. No statistical difference was indicated. The authors concluded that yohimbine was no better than the placebo as a first-line treatment for mixed-type impotence.
Researcher A. Morales, stated that, “Yohimbine has been used for over a century in the treatment of erectile dysfunction. In-depth, systematic studies in animals have shown that the drug has a remarkable positive effect on sexual performance. Meta-analyses of the few controlled, randomized human studies have consistently shown an advantage of yohimbine over placebo. Despite such a long history and encouraging activity, the drug has not yet been subjected to rigorous human clinical trials.”
A 2006 study in the journal Research in Sports Medicine, by Serbian researcher Sergej M. Ostojic, determined the effects of yohimbine supplementation on body composition and exercise performance in professional soccer players. The athletes (20 top-level male soccer players) were allocated to two randomly assigned trials. Subjects in the yohimbine group orally ingested tablets that contains yohimbine at a dose of 20mg/day in two equal doses for 21 days. Subjects in the placebo group ingested an equal number of identical-looking pills. There were no statistically significant changes in body mass and muscle mass within or between trials after the supplementation protocol. Percentage of body fat significantly decreased in the yohimbine group after the supplementation protocol. Furthermore, fat mass was significantly lower in the yohimbine versus placebo trial at post-supplementation assessment. There were no changes in exercise performance indicators (bench and leg press, vertical jump, dribble and power test results, shuttle run) within or between trials. No subject reported any side effects from yohimbine.
A 2010 study in the Journal of Sexual Medicine, by Canadian researcher Dr. Rany Shamloul, stated that, “There is little evidence from literature to recommend the usage of natural aphrodisiacs for the enhancement of sexual desire and/or performance. Data on yohimbine’s efficacy does not support the wide use of the drug, which has only mild effects in the treatment of psychogenic ED… Potent men and women with ED will continue the search for natural aphrodisiacs despite the current disappointing data on their effectiveness.”
A 1997 study in the Archives of Sexual Behaviour, by David L. Rowland & team, assessed the effect of 30mg/day of yohimbine on a group of men with erectile problems and a sexually functional comparison group. The men were examined for sexual desire, arousal, and ejaculatory response. Results indicated no effect of yohimbine on most aspects of sexual response in sexually functional men. Mixed effects were found on measures of sexual function in men erectile dysfunction, with 3 of 11 men reporting strong positive effects. Under yohimbine, frequency of sexual activities increased.
A 2002 study in the journal European Urology, by a French research team led by Thierry Lebret, compared the efficacy and safety of the combination of 6g of L-arginine glutamate and 6mg of yohimbine hydrochloride with that of 6mg of yohimbine hydrochloride alone and that of placebo alone, for the treatment of erectile dysfunction, on 45 men. This pilot study shows that the on-demand oral administration of the L-arginine glutamate 6g and 6 mg yohimbine combination is effective in improving erectile function in patients with mild to moderate ED.
Acc. to a 2013 report in the journal Pharmacognosy Review, by an Indian research team led by Dr. Sabna Kotta , yohimbine is the only herb listed for sexual function the Physician’s Desk Reference. Yohimbine has earned the nickname “herbal viagra.”
A 2002 study in the journal Medical Hypothesis, by US researcher Mark F. McCarty , found that, administering yohimbine prior to exercise, boosts lipolysis and serum free fatty acid levels both during and following exercise. A combination of caffeine and yohimbine can be a potent one to explore in this sense.
Acc. to examine.com, “dosages of 0.2mg/kg bodyweight have been successfully used to increase fat burning without significant implications on cardiovascular parameters like heart rate and blood pressure. This results in a dosage of:
- 14 mg for a 150lb person
- 18 mg for a 200lb person
- 22 mg for a 250lb person
Supplementation is most effective between meals or during short term fasting.”
As a conclusion, there are primarily two areas for which yohimbine use is considered useful, i.e. sexual dysfunction and fat burn. For fat burn, it does work, but it’s also accompanied by a range of side effects. It is similar to ephedra in terms of its side effects, which is another substance proven to burn fat.
Just like the ECA stack, when yohimbine is combined with other stimulants like caffeine or ephedra, it becomes extremely potent and its side effects may outweigh its benefits. However, the effects of yohimbine are more pronounced as a diuretic which may lead to more water loss than fat loss.
Yohimbine toxicity is a proven effect and quite potent one for that, so be careful before administering it.