Tongkat Ali
Eurycoma longifolia
Also known as: Malaysian Ginseng, Longjack
Overview
Tongkat ali (Eurycoma longifolia) is a Southeast Asian root traditionally used to support male vitality and libido. Small human trials suggest it can modestly raise testosterone, most reliably in men who start out with low levels — but the evidence base is thin (a handful of small studies, mostly using one commercial extract), results across trials are mixed, and a couple of trials found no benefit over placebo at all.
Proposed mechanism
Compounds in the root — quassinoids and a peptide fraction sometimes called "eurypeptides" — are thought to support testosterone production in the testes and possibly blunt cortisol's suppressive effect on testosterone during stress. Most of this mechanistic evidence comes from animal and lab-dish studies, not humans. The one human trial that directly measured it found testosterone rose without the expected changes in LH or SHBG — so exactly how tongkat ali works in people is still unclear.
Mechanisms describe how researchers think a compound may act, often from laboratory work — a proposed mechanism is not proof of a clinical effect in people.
Traditional & studied uses
Related pathways
Pathway tags are a research aid for browsing the glossary — they are not a claim that this ingredient treats any condition.