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PreclinicalResearch compoundModerate evidence

Tongkat Ali

Malaysian “longjack”, quassinoids + eurycomanone, testosterone support.

AdaptogenPerformance BoosterAdaptogenHerbAnti-fatigueDopamine

Pharmacology

ClassAdaptogen · Herb
Primary targetCortisol reduction
Targets4 receptor targets
EvidenceModerate evidence
Affected systemsAnti-fatigueDopamine

Contents

WHAT IS TONGKAT ALI?

Detailed overview

Tongkat Ali (Eurycoma longifolia, "longjack") is a Southeast Asian root herb. Its actives are quassinoids (notably eurycomanone) and a glycoprotein fraction (Physta® extract). RCT evidence: Tambi 2012 (PMID 22458760) – 46.8% serum testosterone elevation in hypogonadal men over 1 month; Talbott 2013 (PMID 23705007) – cortisol reduction + testosterone elevation under chronic stress. In eugonadal healthy men the effect is smaller (~15-20%) – the action has a "ceiling-effect" tied to baseline. Best indication: chronic stress + low libido + sleep disturbance combination. NOT on the WADA prohibited list. In athletes, a standard Physta® extract 200 mg/day on a 5-day-per-week cycle protocol is common.

Mechanism

SHBG reduction + cortisol modulation

Onset

2-12 weeks chronic use

Legal status

OTC dietary supplement

Receptor profile

  • CortisolModerate
  • Free testosterone / SHBG bindingModerate
  • Steroidogenesis (eurycomanone)Moderate
  • Libido and sexual functionModerate

Safety

Side effects, stop signs, contraindications

Side effects · 6

  • Insomnia, restlessness or irritability, especially with late-evening dosing (mild stimulating effect)
  • Digestive upset: heartburn, nausea, mild diarrhea at higher doses
  • Increased libido and restless energy, which some users find subjectively uncomfortable
  • Headache, feeling of warmth or increased sweating (anecdotal)
  • Elevated blood testosterone, which in sensitive users may cause acne or heightened aggression
  • Rare, isolated mild transient liver enzyme elevation (main risk with heavy-metal-contaminated, non-standardized extracts)

Contraindications · 6

  • Pregnancy and breastfeeding: avoid due to hormonal activity and insufficient safety data
  • Hormone-sensitive conditions: prostate cancer, BPH or androgen-dependent tumors only under medical supervision
  • Diabetes / antidiabetic use: tongkat ali may lower blood glucose, risk of additive hypoglycemia
  • Avoid alongside TRT or anabolic steroids (additive androgen load, raised hematocrit)
  • Antihypertensives, anticoagulants: use only standardized, heavy-metal-tested extract due to possible interactions
  • With insomnia or anxiety, avoid evening dosing (stimulating effect)

Related Nootropics

Same therapeutic category

FAQ

FAQ

Tongkat Ali is the root of a Southeast Asian herb traditionally used to naturally support male testosterone levels. Human studies have shown it can raise serum testosterone, which is why it's commonly used as a supplement to support hormonal balance and vitality.

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Structure & chemistry

TypeAdaptogen
FormulaC19H24O6
UpdatedJune 19, 2026
MolekulaX Editorial Team·Source-verified · PubMed · FDA · EMA
Updated: June 19, 2026

The information here is strictly for educational and scientific purposes. It does not replace medical advice or clinical consultation, and it does not encourage illegal substance or pharmaceutical use. Data is sourced. When in doubt, consult your doctor.