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Tongkat ali

Eurycoma longifolia

Also calledAli's umbrella · Malaysian ginseng (Malaysia) · Pasak bumi (Indonesia) · Bedara pahit (Indonesia) · Ian-don (Thailand) · Cay ba benh (Vietnam) · Tho nan (Laos) · Long Jack

A slender tree of Southeast Asian forests whose bitter roots are a famous Malay and Indonesian folk tonic for men's vigour and for intermittent fever. Small trials, mostly of one commercial water extract, suggest modest rises in testosterone, especially in men with low levels; evidence for erectile function is mixed.

What it is used for

Sexual function and libido
Limited
A 2022 meta-analysis of five RCTs (nine studies reviewed) found a significant rise in total testosterone (SMD 1.35), also in the subgroup of men with hypogonadism, mostly with one water extract at 100–600 mg daily; the authors said more research is needed before clinical use. A 2015 meta-analysis of two RCTs (139 men) found no overall effect on erectile function scores, though men with worse baseline scores improved.^1,2
Fertility
Limited
In an uncontrolled study cited by a 2016 review, 350 men given 200 mg of extract daily showed improved semen parameters over 9 months, with 11 spontaneous pregnancies among partners; controlled trials are lacking.³
Malaria
Traditional
One of Southeast Asia's best-known folk remedies for intermittent fever; root quassinoids act against Plasmodium falciparum in the laboratory, but there are no clinical trials.³
Fever
Traditional
Root bark is used in folk medicine for fever and diarrhoea.³
General tonic
Traditional
Used as a power tonic after childbirth and promoted in Malaysia as an adaptogen; not tested for these purposes.³

How it is prepared

decoction

Traditionally the root is boiled in water and the decoction drunk.

Sexual function and libido · Malaria

dry extract / capsule

Capsules of standardised water extract of root.

Trials in the 2022 meta-analysis used 100–600 mg daily, for 3 days to 6 months; 200 mg daily was used in men with hypogonadism.

Sexual function and libido

Amounts are as recorded by the named source, not a recommendation.

Safety

Pregnancy: Insufficient data
Breastfeeding: Insufficient data
Children: Not suggested for children for lack of data (Rehman 2016).

Interactions with medicines

propranololModerateA water extract decreased the bioavailability of propranolol in healthy men.
diabetes drugsMinorLowered blood glucose in animals while unpublished human data hint at raised glucose; caution advised.
CYP1A2, CYP2A6 and CYP2C19 substratesMinorWeak, concentration-dependent inhibition in vitro; clinical relevance unknown.

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Do not use if

Hormone-sensitive conditions and suspected prostate disease: raises testosterone, a theoretical prostate risk in older men
Weakened immune system, heart, kidney or liver disease, or sleep apnoea (secondary sources cited by Rehman 2016)

Side effects

Gastrointestinal symptoms and itching in one trial
A case of acute liver injury with jaundice in a 47-year-old man, resolving after stopping (2024)
A probable case of new atrial flutter in a 71-year-old man (2025)

Toxicity

Oral LD50 in mice: 1,500–2,000 mg/kg for alcoholic extract and over 3,000 mg/kg for water extract; rat studies found no adverse effects at up to 2 g/kg/day for 13 weeks, though some blood measures shifted.

In the healing traditions

Southeast Asian (Jamu, Thai, Philippine…)
Tongkat ali (Malay, 'Ali's walking stick'); Pasak bumi (Indonesia)
Root decoction drunk as an aphrodisiac and for intermittent fever (malaria); also for lumbago, indigestion, jaundice, cachexia and dropsy, and as a tonic after childbirth. Leaf decoctions wash itches, the fruit is used for dysentery, the bark as a vermifuge, taproots for high blood pressure and root bark for diarrhoea and fever.
Modern pharmacology
Standardised water extract (e.g. Physta)
Capsules, teas and coffees sold widely; over 200 products were registered with Malaysia's National Pharmaceutical Control Bureau by 2016, sold there as a traditional herbal medicine. Tested mainly for testosterone, male sexual health and exercise.

Active compounds

quassinoids (eurycomanone, eurycomanol, eurycomalactone and others): the main root constituents; antimalarial and cytotoxic in lab studies; eurycomanone linked to testosterone effects in animals
canthin-6-one and β-carboline alkaloids: antiparasitic and anti-inflammatory in lab work

History

Its Malay name means 'Ali's walking stick', referring either to its aphrodisiac reputation or to its long twisted roots. Although used for generations in Malaysia, its safe dosage and toxicity began to attract research attention only in the late 1990s; today it is sold as raw root powder, capsules and additives to teas and coffees.

Sources

Reference, not prescription. Nothing here is medical advice. Herbs can interact with medicines and be dangerous in pregnancy; tell your doctor or pharmacist about anything you take.