Yohimbine
Yohimbine is an alpha-2 adrenergic receptor antagonist derived from the bark of Pausinystalia johimbe. By blocking alpha-2 receptors it increases noradrenaline release and can promote mobilisation of stubborn fat, particularly when fasted. Its use is limited by anxiety, raised blood pressure and heart rate, and it interacts significantly with other stimulants and several drug classes.
01 Overview
Yohimbine antagonises presynaptic alpha-2 adrenergic receptors, which normally act as a brake on noradrenaline release. Blocking them increases sympathetic tone and lipolysis, and because alpha-2 receptors are dense in stubborn fat depots, yohimbine is used to target these areas, with better effect in the fasted state. It has also been studied for erectile dysfunction.
Human fat-loss data are mixed and mostly from small studies, giving it a moderate evidence base. The main limitations are its side-effect profile: anxiety, jitteriness, elevated blood pressure and heart rate, and a narrow tolerability window that varies widely between individuals. It interacts with MAO inhibitors, other stimulants and blood-pressure medications, and can provoke panic in susceptible people.
02 Mechanism
Selective alpha-2 adrenergic receptor antagonist. Blocking presynaptic alpha-2 autoreceptors increases noradrenaline release and sympathetic tone, promoting lipolysis, especially in alpha-2-dense fat depots.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Low | 2.5–5 mg | Oral | Low starting dose to assess tolerance. |
| Common | 5–10 mg | Oral | Often dosed ~0.2 mg/kg, taken fasted; total daily use varies. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Fat mobilisationIncreased lipolysis, with some evidence for targeting stubborn (alpha-2-dense) fat, particularly fasted. | modest, region-dependent | Observational | |
| Increased alertnessRaised sympathetic tone produces stimulant-like alertness. | stimulant-like | Observational |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Anxiety and panicAnxiety, jitteriness and, in susceptible individuals, panic attacks. | Moderate | Common | Clinical | |
| Raised blood pressure and heart rateIncreased blood pressure and heart rate, more pronounced with higher doses or in hypertensive users. | Moderate | Common | Clinical | |
| Drug interactionsSignificant interactions with MAO inhibitors, antihypertensives and other stimulants. | Moderate | Context-dependent | Clinical |