Tongkat ali, also called longjack or Eurycoma longifolia, is a shrub native to Southeast Asia. Its root has a long history as a traditional tonic for men, and it has become a popular ingredient in testosterone and libido supplements.
What human studies suggest
The research is smaller than for ashwagandha, but several findings stand out:
- Men with low testosterone: small studies in men with late-onset low testosterone reported improvements in testosterone levels after about a month of daily use.
- Stress hormones: a trial in moderately stressed adults reported lower cortisol and higher testosterone, along with better mood scores, after four weeks.
- Libido and sexual function: some small trials report improvements in questionnaire scores for sexual wellbeing.
- Men with normal levels: the evidence is weaker and less consistent.
Bottom line: promising but preliminary. Most studies are small, short and use specific standardized extracts, so results may not transfer to every product.
Typical doses
Most studies used 200–400 mg per day of a standardized water extract, taken for 4 to 12 weeks. Raw root powder is less studied.
Considering a supplement for testosterone support?
Testosil: A popular daily testosterone-support formula. Check the label for current doses.
Visit the official Testosil site Read our review
Alternative: TestRX. Positioned for men who train and want support for strength and recovery.
Supplements aren’t a substitute for medical care. We may earn a commission from purchases through these links.
Quality is the big issue
Because tongkat ali is expensive and grown in a limited region, quality varies widely. Testing of products sold in Southeast Asia has found some contaminated with heavy metals such as mercury and lead. Choose brands that:
- Use a named, standardized extract
- Publish third-party testing for contaminants
- List the exact dose rather than hiding it in a blend
Safety
Tongkat ali appears well tolerated at studied doses in the short term. Reported side effects include restlessness and trouble sleeping. It is not recommended for men with hormone-sensitive conditions such as prostate cancer, and anyone taking medication should check with a doctor first.
Where it fits
Tongkat ali is best seen as a supporting ingredient, not a stand-alone fix. Compare formulas that include it in our testosterone support guide.
Is tongkat ali better than ashwagandha?
They have different research profiles. Ashwagandha has more trials overall; tongkat ali has interesting results in men with low testosterone and high stress. Neither has strong, large-scale evidence.
How long does tongkat ali take to work?
Most studies measured changes after 4 to 12 weeks of daily use.
Can I take tongkat ali every day?
Studies used daily dosing for up to a few months. Long-term safety data is limited, so many people cycle it.