Hype checkGrade C — proceed with skepticism

Tongkat Ali

A Southeast Asian herb with emerging but limited human evidence for testosterone support, stress reduction, and physical performance.

By editorialUpdated 2026-05-251 min read

The evidence isn't there yet.

A handful of small RCTs show modest increases in free testosterone and reductions in cortisol and tension scores, primarily in stressed or aging populations. Effect sizes are small and study quality is generally moderate.

What it's actually good for

Tongkat ali (Eurycoma longifolia) is a plant native to Southeast Asia with traditional use as a tonic and aphrodisiac. Modern research has focused on its potential to support testosterone levels, reduce perceived stress, and improve physical performance. A small number of RCTs suggest it may modestly increase free testosterone (particularly in men with suboptimal levels) and reduce cortisol, with associated improvements in mood, energy, and body composition. However, most studies are small, short-term, and some have industry funding. The evidence is more encouraging than many "testosterone boosters" but still falls short of a confident recommendation. It may offer mild support for stress-related fatigue and age-related hormonal decline, but should not be expected to produce dramatic performance or hormonal changes.

Claim-by-claim

Each claim graded independently

The overall grade is the floor. Some claims are stronger or weaker than the headline.

C

Tongkat ali may modestly increase testosterone levels and reduce cortisol in stressed adults

A handful of small RCTs show modest increases in free testosterone and reductions in cortisol and tension scores, primarily in stressed or aging populations. Effect sizes are small and study quality is generally moderate.

Sources

1 cited
[01]GOVTTongkat AliNational Center for Complementary and Integrative Health (NCCIH). 2024

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