Pausinystalia & Corynanthe Bark Trees
The yohimbine/corynanthine-bearing Rubiaceae beyond 'yohimbe'
Evidence grade 2 of 5, Thin. Read how the Atlas grades evidence.
The written rationale for this grade is still being prepared.
- FDA
- Crude barks unapproved; isolated yohimbine HCl is a legacy Rx, OTC yohimbe barks are not FDA-evaluated
Reference only. Not medical advice.
What can go wrong
Crude yohimbe bark carries the full yohimbine risk set (hypertension, tachycardia, anxiety, panic, GI upset, and serious interactions with MAOIs, stimulants, and antihypertensives) compounded by dose uncertainty. Poison-control and FDA adverse-event data link yohimbe products to cardiovascular events and seizures. The unpredictable potency makes crude bark arguably riskier than a measured yohimbine dose.
This is something to take to a clinician. The Atlas can tell you what is known about pausinystalia & corynanthe bark trees in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
The 'yohimbe' of commerce is the bark of Pausinystalia johimbe (syn. Corynanthe johimbe), a West/Central African rainforest tree of the Rubiaceae. The related genus Corynanthe (e.g. C. pachyceras, C. mayumbensis) and Rauvolfia share overlapping indole-alkaloid chemistry. This entry covers the broader plant complex rather than the pharmacology of purified yohimbine. Crude barks contain yohimbine alongside dozens of stereoisomers and related alkaloids (corynanthine, corynantheine, rauwolscine/alpha-yohimbine), in wildly variable and frequently mislabeled amounts. Analyses of US yohimbe supplements have repeatedly found yohimbine content bearing little relation to the label, ranging from undetectable to several-fold higher than stated.
The botanical genus behind yohimbe is messier - and more adulterated - than the label says.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
How it is supposed to work
The pharmacologically dominant alkaloid, yohimbine, is an alpha-2 adrenoceptor antagonist that increases noradrenergic outflow and penile blood flow; its stereoisomer corynanthine is comparatively alpha-1 selective, and rauwolscine (alpha-yohimbine) is a potent alpha-2 antagonist with 5-HT activity. Because crude bark is an uncontrolled mixture of these isomers, the net adrenergic effect of any given product is unpredictable.
Yohimban-type indole alkaloids: pentacyclic structures differing mainly in stereochemistry at key carbons, which is why corynanthine, yohimbine, and rauwolscine are isomers with divergent receptor profiles despite near-identical molecular formulae.
'Bark' is not 'yohimbine'
Consumers and even some sellers treat 'yohimbe bark' and 'yohimbine' as synonyms. They are not. Crude bark delivers a variable cocktail of alpha-1 and alpha-2 active stereoisomers plus other alkaloids, so cardiovascular and CNS effects cannot be predicted from a yohimbine dose, and label content is notoriously unreliable.
Safety in detail
- Label yohimbine content often inaccurate (analyses found 0 to >150% of stated)
- Alpha-1/alpha-2 isomer mix makes cardiovascular response unpredictable
- Dangerous interactions with MAOIs, stimulants, SSRIs, antihypertensives
- Banned or restricted as an OTC ingredient in several countries
What people get wrong
Often saidYohimbe bark equals pharmaceutical yohimbine
ActuallyCrude bark is an unstandardized alkaloid mixture; its potency and isomer ratio vary unpredictably and are frequently mislabeled.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
How we got here
Indigenous peoples of West and Central Africa used Pausinystalia bark as a stimulant and aphrodisiac long before German colonial physicians isolated yohimbine around 1896 and brought it into European medicine. The crude bark trade and the purified-alkaloid pharmacology then diverged: one became an unregulated supplement, the other a defined Rx molecule.
The people taking it
Wild bark is harvested in Cameroon, Gabon, Nigeria and the DRC, often destructively (ring-barking kills trees), raising sustainability concerns for P. johimbe. Crude bark and extracts are exported worldwide for the supplement trade.
What we do not know
- Can a sustainable, standardized P. johimbe supply chain exist, or should only purified yohimbine be used?
- How much of crude-bark toxicity is from rauwolscine and corynanthine rather than yohimbine?
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Among the worst-documented adulteration and potency-variability problems in the botanical aphrodisiac trade; independent assays repeatedly find label-content mismatches.
Central AfricaWild bark harvest, frequently unsustainable ring-barkingExport brokersBulk bark and crude extract shipped to North America/EuropeSupplement makersRepackaged as 'yohimbe' capsules of uncertain potency
At a glance
- Botanical source
- Pausinystalia johimbe (Rubiaceae)
- Related genera
- Corynanthe, Rauvolfia
- Key alkaloids
- Yohimbine, corynanthine, rauwolscine, corynantheine
- Native range
- Cameroon, Gabon, Nigeria, DRC
- Label accuracy (US studies)
- Frequently inaccurate or undetectable
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Pausinystalia & Corynanthe Bark Trees. A short entry is not a safe entry.
- Timeline. We have not built the dated record of research and regulatory events.
- Cost and market. We have not documented what it sells for or who sells it.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
Sources
The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.
The studies that matter
Cohen et al., analysis of US yohimbe supplements2016
Found highly inconsistent yohimbine quantities and frequent failure to declare amounts; many products mislabeled
Historical yohimbine HCl ED trials1980s-1990s
Modest erectile benefit for purified yohimbine over placebo; do not validate crude bark