We use essential cookies (authentication, your saved goals/stack) by default. With your permission we'll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more
Eurycoma longifolia (Longjack)
Southeast Asian herb with evidence for supporting healthy testosterone levels, energy, and stress resilience.
What the evidence says
Tongkat Ali appears to help in 3 of 4 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2010–2024 with a typical study size of 84 participants.
Based on 17 studies · 2 meta-analyses · 7 RCTs · 1,144 total participants
Confidence
HighWhat the studies found
By outcome
See full supplement plans that include Tongkat Ali.
Tongkat Ali has an evidence score of 7/10 — strong evidence based on 17 indexed studies, including 2 meta-analyses. Southeast Asian herb with evidence for supporting healthy testosterone levels, energy, and stress resilience.
The commonly studied dose of Tongkat Ali is 200-400mg standardized extract. Research points to an estimated optimal dose around 400mg, with a minimum effective dose near 200mg. Individual response varies — start low and adjust.
The best time to take Tongkat Ali is in the morning. Taking it with food is preferred. Tongkat ali (Eurycoma longifolia) contains eurypeptides, quassinoids, and alkaloids that support testosterone production via HPA axis modulation and aromatase inhibition.
Last reviewed May 2026 · evidence from 15 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Tongkat Ali is a flowering plant native to Southeast Asia, traditionally used as an aphrodisiac and energy tonic. Research shows it may support healthy testosterone levels, particularly in men with suboptimal levels or high stress. Also shows adaptogenic properties, helping manage cortisol and stress response.
May support natural testosterone production
Helps balance the stress hormone cortisol
How Tongkat Ali works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
200-400mg standardized extract
Can be taken without food
| Form | Type |
|---|---|
| 💊Standardized root extract (100:1 or 200:1) | Recommended |
| 🧪Root powder (requires higher doses) | Alternative |
Standardized extracts are more reliable. Look for products tested for heavy metals and contaminants.
Minimum: 4 weeks
Optimal: 8 weeks
Cycling: 5 days on, 2 days off. Or 4 weeks on, 1 week off. Cycling may prevent tolerance.
Note: Some prefer taking in the morning due to potential energizing effects. Standardized to eurycomanone content (1-2%).
Based on meta-analysis showing significant testosterone elevation and multiple RCTs. Effects varied between healthy volunteers and hypogonadal men. Studies primarily used standardized water extracts.
May increase total and free testosterone
Improved energy and reduced fatigue
Lower stress and improved mood
Avoid — affects hormones
Use with caution; may affect hormone levels
May have additive effects
May affect blood pressure
May affect blood sugar
Tip: Take in morning; reduce dose
Tip: Reduce dose
Tip: May be normal; reduce dose if uncomfortable
Both support testosterone and reduce cortisol
Enhanced hormonal support and stress management
Zinc is essential for testosterone production
Comprehensive testosterone support
Both support male hormonal health
Enhanced testosterone and vitality support
Different mechanisms for hormonal support
Enhanced energy and libido support
Commonly stacked for testosterone support via different mechanisms
Tongkat ali frees bound testosterone while fadogia increases LH signaling
Tongkat Ali is generally safe at recommended doses, with a few precautions worth noting. The most commonly reported side effects are insomnia, restlessness, increased body temperature. Use caution if any of these apply to you: Hormone-sensitive cancers; Heart conditions; Immune disorders.
Shatavari
Likely helpsPremier women's tonic in Ayurveda that supports reproductive hormones, fertility, and lactation — the female counterpart to ashwagandha.
Tap node to isolate • Pinch to zoom • Tap edge for research