Eurycoma Longifolia

botanicaleurycomanone

What is it

Eurycoma longifolia, commonly called tongkat ali or longjack, is a small evergreen tree native to Southeast Asia. Its roots have been used traditionally for sexual function, fatigue, and as a general tonic, and modern supplements market it for testosterone support, libido, and athletic performance.

How it works

E. longifolia root contains a complex mixture of quassinoids (including eurycomanone), alkaloids, and other compounds. Eurycomanone has been studied for effects on steroid synthesis pathways, with some evidence suggesting it may inhibit aromatase (the enzyme that converts testosterone to estrogen) and influence steroidogenic enzymes in animal and laboratory studies. In human trials, standardized E. longifolia extracts have shown modest increases in free testosterone, particularly in men with low or borderline testosterone, and modest decreases in cortisol in stressed individuals. The combined ratio change (testosterone-to-cortisol) has been interpreted by some researchers as supporting an 'anti-stress' or 'restorative' effect. Proposed mechanisms also include effects on energy metabolism, mood, and physical performance via the testosterone-cortisol axis. Research quality has improved with use of standardized extracts (such as the patented Physta extract, standardized to 22 percent eurypeptides, 30 percent polysaccharides, and 40 percent glycosaponins), though most clinical trials remain small.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Male testosterone (men with low/borderline T)

Grade C

Moderate evidence

Trials of standardized extracts (Physta, LJ100) in men with low testosterone or in older men show modest increases in free and total testosterone over weeks. Effects in men with normal baseline testosterone are smaller.

Stress and cortisol reduction

Grade C

Moderate evidence

Small trials in chronically stressed individuals report modest reductions in cortisol and improved mood markers with daily standardized extract use.

Libido and sexual function

Grade C

Moderate evidence

Some trials report modest improvements in libido and self-reported sexual function in men. Effects are typically modest and emerge over weeks.

Athletic performance and muscle mass

Grade D

Mixed evidence

Mixed results in athletic performance trials. Some studies report modest gains in strength or lean mass; others show no significant difference from placebo.

Energy and fatigue

Grade D

Mixed evidence

Traditional use for fatigue is supported by limited modern clinical evidence. Effects may overlap with stress and cortisol changes.

4 commercial forms

Physta standardized extract

Standardized to 22% eurypeptides, 30% polysaccharides, 40% glycosaponins

Patented extract used in most modern clinical trials. Provides consistent dosing of bioactive markers.

LJ100 (Eurycomanone-standardized)

Standardized to 28% bioactive eurycomanone

Another well-studied standardized extract.

Concentration ratio extracts (100:1, 200:1)

Less standardized; quality varies

Common in mass-market supplements. Ratio indicates raw root to extract weight, but does not guarantee bioactive content.

Whole root powder

Less concentrated, traditional form

Used in traditional Southeast Asian preparations. Variable potency.

Dosage

There is no established RDA. Clinical trials with standardized extracts (e.g., Physta, LJ100) typically use 100 to 400 mg per day. Lower-purity extracts (often labeled with concentration ratios like 100:1 or 200:1) commonly use 200 to 600 mg per day. Effects on testosterone, libido, and stress markers usually emerge over 4 to 12 weeks of consistent daily use.

When and how to take it

Take E. longifolia in the morning or early afternoon to avoid potential sleep disturbance. It can be taken with or without food, though taking with breakfast may reduce mild gastrointestinal effects. Daily use over 4 to 12 weeks is typical before judging effects. Cycling (8 to 12 weeks on, 2 to 4 weeks off) is suggested by some practitioners, though not strictly evidence-based.

Safety

E. longifolia at typical supplement doses is generally well tolerated. Side effects are uncommon and may include mild restlessness, insomnia (especially with evening dosing), and gastrointestinal upset. Some products have been found to contain mercury contamination, so choose products from reputable manufacturers with third-party testing. There is no established Tolerable Upper Intake Level. Long-term safety beyond several months is not well established.

Who should be cautious

Avoid in pregnancy and breastfeeding due to insufficient safety data and potential hormonal effects. Avoid in people with hormone-sensitive cancers (breast, prostate). Use caution if you have cardiovascular disease, diabetes, weakened immunity, sleep apnea, or kidney/liver disease. Not recommended for adolescents. Discontinue at least two weeks before scheduled surgery. Choose products with verified low mercury content.

Interactions

E. longifolia may interact with diabetes medications by enhancing glucose-lowering effects. Possible interactions with immunosuppressant medications due to immune-modulating properties. May interact with antihypertensives. Possible additive effects when combined with other testosterone-boosting or hormone-modulating supplements. Discuss use with a clinician if you take prescription medications.

Frequently asked questions

Does tongkat ali really boost testosterone?⌄

Standardized extracts have shown modest free testosterone increases in men with low or borderline levels. Effects in men with normal testosterone are smaller. It is not a substitute for medical testosterone therapy when clinically indicated.

How long until I notice effects?⌄

Clinical effects typically emerge over 4 to 12 weeks of daily use. Acute single-dose effects are minimal.

Is tongkat ali safe long-term?⌄

Most studies have run 8 to 12 weeks. Long-term safety beyond several months is not well established. Some practitioners cycle use (weeks on, weeks off).

What's the difference between Physta and other tongkat ali products?⌄

Physta is a patented standardized extract used in most modern clinical trials. It provides consistent levels of multiple bioactive markers. Non-standardized 'tongkat ali' products vary widely in actual bioactive content.

Can women take tongkat ali?⌄

Most research has been in men. Some women use it for energy and stress, but effects on female hormones are not well studied. Avoid in pregnancy, breastfeeding, and hormone-sensitive conditions.

References

ChEBI: eurycomanone — ChEBI Database link
Wikidata: Eurycoma longifolia — Wikidata link

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Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.