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Yohimbine
Selective α2-adrenergic antagonist | Pausinystalia johimbe alkaloid — fasted-state lipolysis enhancer + pre-Viagra ED tool, with strong anxiogenic ceiling at higher doses
Aliases (8)
Overview
What is Yohimbine?
Yohimbine is an indole alkaloid extracted from the bark of the West African Pausinystalia johimbe tree. Pharmacologically, it is a relatively selective antagonist at α2-adrenergic receptors (with weaker activity at α1, 5-HT1A, and dopamine D2 sites). It was previously available as a prescription drug for erectile dysfunction (Yocon, Aphrodyne — yohimbine HCl 5.4 mg) but is now sold predominantly as an OTC supplement in the US. It is not WADA-prohibited.
Key Benefits
Fasted-state fat oxidation enhancer (most useful for already-lean lifters trying to mobilize stubborn α2-rich adipose depots); historic off-label tool for erectile dysfunction (now mostly displaced by PDE5 inhibitors); short-acting situational pre-cardio agent.
Mechanism of Action
Blocks the presynaptic α2-adrenergic autoreceptor — the negative-feedback receptor that normally tells noradrenergic neurons to stop releasing norepinephrine. With the brake released, NE release rises in both adipose tissue (where α2 dominates β-adrenergic lipolysis in stubborn fat depots) and the central nervous system (locus coeruleus disinhibition). The same mechanism that delivers the lipolytic and ED-rescue effects also produces the anxiogenic / panic ceiling at higher doses. Insulin opposes the cAMP rise downstream of α2 blockade, so fed-state dosing largely abolishes the fat-oxidation effect.
Pharmacokinetics
Peptide Interactions
the entire evidence base assumes this combination.
replenish sweat losses; mitigate orthostatic symptoms.
theoretically — substrate for ongoing NE synthesis under elevated sympathetic demand. No RCT data; mechanistically reasonable.
Cumulative sympathetic load — anxiety + BP + HR + arrhythmia risk superlinear. The combination behind most fat-burner ER visits. If pairing, cap caffeine at …
Additive HR/BP load + anxiety; both increase sympathetic tone via different mechanisms.
Stacked α + β + sympathomimetic effects. Anxiety, BP spike, arrhythmia risk. Hard avoid.
Hypertensive crisis risk. Absolute contraindication. 14-day washout required.
(loses MAO-B selectivity): same MAOI concern at higher doses.
Raise yohimbine plasma 5-10x → unpredictable toxicity at standard supplement doses.
NE/QT compound risk.
Cumulative sympathomimetic stacking. Hard avoid.
Direct receptor competition. Yohimbine antagonizes their BP-lowering and ADHD-augmenting effects.
Quality Indicators
Standardized yohimbine HCl, third-party tested
USP-grade or NSF-tested yohimbine HCl from a reputable supplement vendor. Should declare exact mg of yohimbine HCl per cap (typically 2.5, 5, or 10 mg). Lot-tested for purity and absence of contaminants.
Clear active-content labeling
Best-in-class supplements list 'yohimbine HCl' with a discrete mg value rather than 'yohimbe bark extract' with no standardization. Yohimbe bark products show massively variable yohimbine content (0.1-15% w/w) batch to batch.
Yohimbe bark extract without standardization
Many cheap supplements list 'yohimbe bark extract' without telling you the yohimbine HCl content. Same brand can vary 100-fold in actual yohimbine content from lot to lot — a 500mg bark capsule might contain anywhere from 0.5 mg to 75 mg yohimbine. This is the single biggest source of overdose / under-dose mismatch in the supplement market.
Unlabeled fat-burner blend with yohimbine
Pre-workout / fat-burner supplements that bury yohimbine inside a proprietary blend without specifying mg. These are responsible for most ER yohimbine cases — users stack them with caffeine, additional pre-workouts, or repeat doses without realizing total alkaloid load.
Non-US gray-market 'rauwolscine' (α-yohimbine)
Rauwolscine (α-yohimbine) is a more selective α2 antagonist marketed in some pre-workouts. Higher potency at α2 + similar anxiogenic profile. Quality control is even worse than yohimbine HCl in the OTC supplement space.
What to Expect
- Week 1Tolerability and dose-response.
- Week 2-4Early effect window.
- Week 4-8Peak benefit assessment.
- Week 8+Cycle decision point.
Side Effects & Safety 11
Side Effects
- 1Anxiety / jitters / racing thoughts — the dose-limiting side effect. Worse in stress-prone users, anxiety-history, fed state, layered with caffeine.
- 2HR rise (5-25 bpm dose-dependent) + BP rise (5-15 mmHg systolic) — universal. Will corrupt HR-zone training data; concerning for combat athletes already running chronic CV load.
- 3Insomnia — even with AM dosing in slow metabolizers; severe with PM dosing.
- 4GI urgency — increased bowel motility, especially fasted state.
- 5Sympathetic flush, hand tremor
- 6Palpitations / PVCs — usually benign but can be alarming in anxiety-prone.
- 7Headache — sympathetic-driven vascular headache pattern.
- 8Nausea — especially fasted state at higher doses.
- 9Dizziness / orthostatic symptoms — paradoxical, mostly in slow metabolizers.
- 10Mild euphoria or anhedonia — variable mood effect across users.
- 11Sweating, dry mouth
When to Stop
- Hypertensive crisis — at very high doses or with MAOI co-administration. Most reported cases involve unstandardized yohimbe-bark products with unknown alkaloid load.
- Cardiac arrhythmia — atrial fibrillation, supraventricular tachycardia. Mostly with stacked sympathomimetic load.
- Panic attacks meeting full DSM-5 criteria — Charney lab work shows ~70-90% panic-induction rate in panic-disorder patients at 20-30mg dose; rarer but documented in healthy controls at higher doses.
- Renal failure (case reports; rare; mechanism uncertain; usually with overdose or contaminated yohimbe bark).
- Hepatitis / hepatotoxicity (case reports of yohimbe-bark — possibly other alkaloids, not yohimbine specifically).
- Suicidal ideation — case reports in psychiatrically vulnerable users; biological plausibility via NE/HPA axis activation.
- Mania switch — in undiagnosed bipolar.
- First 3-5 doses: characterize HR/BP response, anxiety, sleep impact.
- First 2 weeks of regular use: check resting BP/HR weekly. If sustained rise, abandon.
- Sleep architecture: even AM-only dosing can degrade REM/deep in slow metabolizers — Oura/sleep tracker on use-days vs off-days for the first 4 weeks.
References
Galitzky et al. 1988 — Effect of yohimbine on adrenergic-mediated lipolysis (PMID 2899551)
foundational fat-cell α2-blockade lipolysis study.
View StudyCharney, Heninger, Breier 1984 — Noradrenergic function in panic anxiety: yohimbine effects (Arch Gen Psychiatry, PMID 6324726)
landmark panic-provocation paper.
View StudyMcCarty 2002 — Pre-exercise yohimbine for fat-loss mechanism (Med Hypotheses, PMID 11859876)
fasted-state requirement framework.
View StudyKearney et al. 2010 — Yohimbine in ED systematic review (PMID 20718941)
modern ED meta-analysis.
View StudyErnst & Pittler 1998 — Yohimbine in ED meta-analysis (J Urol, PMID 9494135)
pre-Viagra meta of 7 RCTs.
View StudyOstojic 2006 — Yohimbine in lean elite soccer players (Res Sports Med, PMID 17214405)
best clinical RCT for the lean-athlete fat-loss use case.
View StudyBremner et al. 1997 — Yohimbine challenge in PTSD (PMID 9210738)
PTSD neuroimaging with yohimbine.
View StudyTam et al. 2001 — Yohimbine clinical review (Pharmacol Ther, PMID 11744129)
comprehensive clinical review.
View StudyLe Corre et al. 1999 — Stereoselective metabolism by CYP2D6 (Drug Metab Dispos, PMID 10421624)
pharmacogenomics paper.
View StudyBerlan 1991 — Plasma yohimbine concentrations after oral dosing in lean subjects
PK / lipolysis.
View StudyLafontan & Berlan 1995 — Fat cell α2 adrenoceptors: the regulation of fat cell function and lipolysis (Endocr Rev)
definitive review of α2 receptor distribution across fat depots.
View StudyMauriège et al. 1991 — Regional differences in adipose tissue lipolytic responsiveness
depot-specific α2 distribution.
View StudyLatest research
- meta-analysisYohimbine in erectile dysfunction — systematic review (Kearney et al.)Modest benefit over placebo (small effect size), now largely displaced by PDE5 inhibitors due to better efficacy and side-effect profile. Useful historical context for ED management, not a current first-line tool.
- rctYohimbine effects on body composition + performance in lean elite soccer players (Ostojic, Res Sports Med)20mg/day x 21 days in 20 lean elite soccer players. Fat mass dropped (-2.2% vs placebo) with no significant change in athletic performance, lean mass, or training metrics. Best evidence for the "lean athletes mobilizing stubborn fat" use case. Anxiety/jitters reported as the dose-limiting side effect.
- reviewPre-exercise yohimbine may enhance exercise-induced fat-loss via lipolysis (McCarty, Med Hypotheses)Mechanistic review formalizing the fasted-state requirement — insulin counteracts cAMP rise downstream of α2 blockade, so fed-state dosing largely abolishes the lipolytic effect. The "fasted morning cardio" supplement protocol traces to this paper.
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