Tongkat Ali (Eurycoma longifolia)
A Southeast Asian root traditional for vitality. Modestly raises free testosterone (mostly by lowering SHBG and cortisol), supports libido, and reduces stress markers.
Moderate evidence for raising free / bioavailable testosterone in men with low baseline (typically older or stressed). Improvements in mood, fatigue, libido. Smaller benefits in men already in healthy range. Effects: 4–8 weeks.
Tongkat ali is a tall Southeast Asian shrub whose roots have been used as a traditional tonic in Malaysia, Indonesia, and Vietnam for centuries. Its main bioactives are quassinoids (eurycomanone is the marker compound). Modern research has focused on its effects on male testosterone status — it doesn't dramatically raise total testosterone production, but it lowers SHBG (sex hormone binding globulin) and cortisol, which raises the bioavailable free testosterone. Effects on libido, mood, and stress resilience are reasonably well-documented in middle-aged men with low baseline androgens.
- Form
- Standardised extract (LongJack 100, Physta) — standardised to ~1–2% eurycomanone or marker compounds. Tongkat Ali by KSM-66 or Akarali — branded forms with good standardisation. Avoid raw root powder of unverified origin (quality varies wildly).
- Dose
- 200–400 mg/day standardised extract. Most trials use 200–300 mg.
- Timing
- AM with food. Some find it mildly activating — avoid PM.
- Schedule
- Cycle: 8 weeks on, 2 weeks off. Continuous use OK for many but cycling preserves sensitivity.
- Side effects
- Generally well-tolerated. Insomnia, irritability, restlessness — usually means dose is too high or too late in day. Mild GI upset.
- Interactions
- Anti-androgen medications — opposing action. Diabetes medications — mild glucose effects. Anticoagulants (mild).
- Contraindications
- Prostate cancer or family history (caution — testosterone-supporting effect). Heart conditions (some quassinoids have cardiac effects at very high doses). Pregnancy.
- Lab markers
- Total + free testosterone, SHBG, cortisol. DHEA-S, estradiol for full picture.
- Food sources
- Not present in everyday food.
Pairs with
Fadogia agrestis (the famous testosterone-support pair — both popularised by Huberman). Ashwagandha (additive stress / cortisol effect). Boron, zinc, vitamin D (hormonal cofactors).
within Herbs & botanicals