Yohimbine Bark Extract
Also known as: Yohimbe bark extract, Aphrodine, Corynine, Quebrachine, 17α-hydroxyyohimban-16α-carboxylic acid methyl ester, Yohimbine
Overview
Yohimbine is a natural alkaloid extracted from the bark of the *Pausinystalia johimbe* tree, native to West Africa. Traditionally used as an aphrodisiac, its primary modern application is in the treatment of erectile dysfunction (ED). It functions as an alpha-2 adrenergic receptor antagonist, increasing sympathetic nervous system activity. While research supports its efficacy for ED, its purported benefits for athletic performance and weight loss are less substantiated. The evidence for yohimbine in ED is relatively mature, with several randomized controlled trials and meta-analyses confirming its effectiveness, though safety data, particularly long-term, remains somewhat limited. It is classified as a natural alpha-2 adrenergic receptor antagonist and is available as a standardized bark extract or pure alkaloid.
Benefits
Yohimbine primarily benefits men with erectile dysfunction (ED). A 1998 meta-analysis of seven randomized controlled trials (RCTs) found a significant improvement in ED, with an odds ratio of 3.85 favoring yohimbine over placebo. More recently, a 2021 systematic review and meta-analysis of eight RCTs confirmed that yohimbine alone improves erectile function (OR = 2.08, p=0.002). This review also highlighted that combining yohimbine with other supplements can further enhance efficacy (OR = 6.35) and significantly improve overall sexual function (OR = 2.65). The benefits are clinically meaningful, particularly in cases of organic ED, including in diabetic patients. Improvements are typically observed within weeks of starting treatment, aligning with its pharmacological action. While its use for general sexual function or athletic performance is less supported, its role in ED is backed by moderate to high-quality evidence from systematic reviews and meta-analyses.
How it works
Yohimbine acts as a selective alpha-2 adrenergic receptor antagonist. By blocking these presynaptic inhibitory receptors, it increases the release of norepinephrine, a neurotransmitter that enhances sympathetic nervous system activity. This leads to improved blood flow, particularly to the penile tissues, facilitating erection through vasodilation. Additionally, yohimbine may increase central nervous system adrenergic activity, which could contribute to enhanced libido and sexual arousal. It is absorbed orally, and its bioavailability can vary among individuals, influencing its overall effectiveness.
Side effects
Yohimbine is generally considered safe at therapeutic doses, but its mechanism of action, which increases sympathetic activity, can lead to several adverse effects. Common side effects, affecting more than 5% of users, include anxiety, increased heart rate (tachycardia), elevated blood pressure, headache, dizziness, and gastrointestinal upset. Less common side effects (1-5%) include insomnia, sweating, and tremors. Rare but serious side effects (less than 1%) can include severe hypertension, cardiac arrhythmias, and psychosis, particularly in cases of overdose or in sensitive individuals. Yohimbine can interact with various medications; caution is advised when used with antihypertensives, MAO inhibitors, stimulants, and other sympathomimetics due to potential additive effects. Contraindications for yohimbine use include uncontrolled hypertension, pre-existing cardiovascular disease, anxiety disorders, and pregnancy. While serious adverse reactions are infrequent and typically reversible in clinical trials, comprehensive safety data, especially for long-term use, remains limited.
Dosage
Effective doses of yohimbine for erectile dysfunction (ED) typically range from 5 to 20 mg per day, often administered in divided doses. The minimum effective dose observed in studies is around 5 mg, with some research utilizing up to 20 mg daily. While a firm maximum safe dose is not established, doses exceeding 30 mg per day are associated with an increased risk of adverse effects. For acute effects, yohimbine is commonly taken 30-60 minutes before sexual activity, though some studies have employed daily dosing for sustained benefits. It is crucial to use standardized pure yohimbine alkaloid for consistent dosing, as the concentration in bark extracts can vary. Absorption may be influenced by food, with some evidence suggesting that taking it on an empty stomach could enhance bioavailability.
FAQs
Is yohimbine effective for all types of ED?
Yohimbine is generally more effective for organic ED, such as that caused by diabetes, than for psychogenic ED. While it can improve erectile function, it may not significantly improve overall sexual function when used alone.
Is it safe to use yohimbine long-term?
Long-term safety data for yohimbine is limited. Short-term use appears safe under medical supervision, but continuous monitoring for adverse effects, especially cardiovascular ones, is recommended for extended periods.
Can yohimbine be combined with other ED treatments?
Some evidence suggests enhanced efficacy when yohimbine is combined with other supplements or PDE5 inhibitors. However, such combinations should be approached with caution and under medical supervision due to potential additive side effects.
What are common misconceptions about yohimbine?
Yohimbine is often marketed as a general aphrodisiac or weight loss aid, but strong scientific evidence for these uses is lacking. Its primary validated and research-backed application is for the treatment of erectile dysfunction.
Research Sources
- https://www.auajournals.org/doi/10.1016/S0022-5347(01)63942-9 – This meta-analysis of seven randomized controlled trials (RCTs) from 1998 found that yohimbine was significantly superior to placebo for improving erectile dysfunction (ED), with an odds ratio of 3.85. It also noted a low incidence of serious adverse events, suggesting moderate quality evidence for its efficacy and safety in the short term.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9612744/ – A 2021 systematic review and meta-analysis of eight RCTs confirmed that yohimbine alone improves erectile function (OR = 2.08). The study also highlighted that combination therapies including yohimbine were even more effective for ED and significantly improved overall sexual function, indicating high-quality evidence for its role in ED treatment.
- https://jmrh.mums.ac.ir/article_10897_98c14611368abc24794ab36b4f0f7592.pdf – This systematic overview of reviews from 2017 consistently confirms the efficacy of yohimbine for erectile dysfunction. It notes that while the methodological quality of some included studies was variable, the overall findings support yohimbine's benefit, providing moderate quality evidence that reinforces earlier research.
