HYPE: Tongkat ali increases testosterone and builds muscle.
But what does the evidence actually show?
Some small human trials support higher total testosterone, particularly in men with low levels. Reliable extra muscle growth is not established, and safety cannot be assumed across extracts.
The hype
Tongkat ali is marketed as a natural route to more testosterone, energy and muscle. The fair question is whether a defined extract produces a useful benefit in a defined population, rather than whether every increase in a blood hormone is automatically beneficial.
Why testosterone is only part of the question
Researchers investigate effects on hormonal regulation, but the pathway alone does not establish extra muscle tissue. Testosterone measurements, strength tests and actual hypertrophy require separate evidence.
Baseline hormone status also matters. Findings in older men with low testosterone should not become a promise for healthy young lifters with normal levels.
What does the evidence show?
Leisegang and colleagues (2022)
Eurycoma longifolia Improves Serum Total Testosterone in Men
Nine studies were reviewed and five randomised trials pooled. Total testosterone increased on average, including in the low-testosterone subgroup. The standardised effect was large but imprecise, and more research was needed before clinical use.
A hormone outcome does not establish muscle growth or superiority to appropriate assessment and treatment of hypogonadism.
Read the research ↗Young men and resistance training (2019)
Effects of Eurycoma Longifolia Jack Supplementation Combined with Resistance Training on Isokinetic Muscular Strength and Power, Anaerobic Power, and Urinary Testosterone: Epitestosterone Ratio in Young Males
Forty men were assigned across four groups for eight weeks. Power improved with training, with or without supplementation. The urinary testosterone-to-epitestosterone ratio did not change significantly. These selected performance results do not demonstrate extra muscle hypertrophy from the supplement.
Read the research ↗European Food Safety Authority (2021)
Safety of Eurycoma longifolia root extract as a novel food
EFSA evaluated a particular standardised water extract and identified genotoxicity concerns from laboratory and animal testing. It concluded that safety of that preparation had not been established under any condition of use.
This is not proof that every product causes DNA damage in humans. It is a substantive reason not to assume universal safety or transfer results freely between extracts.
Read the research ↗The catch / limitations
Different extracts are different interventions. Product composition and quality can vary.
Hormones are not physique outcomes. A biomarker change cannot quantify extra muscle gained.
The target population is uncertain. Evidence in low-testosterone men cannot be assigned to everyone seeking better performance.
What this means for you
If symptoms suggest low testosterone, seek assessment rather than diagnosing yourself from fatigue or gym progress. Appropriate testing needs clinical context.
For muscle growth, progressive resistance training and adequate nutrition have a clearer basis. Discuss a supplement with a pharmacist or clinician, particularly with medicines or an existing condition.
Tongkat ali has a signal for testosterone in selected men. A dependable muscle-building promise goes further than the evidence.
Research & Sources
Leisegang and colleagues (2022)
Eurycoma longifolia Improves Serum Total Testosterone in Men
Young men and resistance training (2019)
Effects of Eurycoma Longifolia Jack Supplementation Combined with Resistance Training on Isokinetic Muscular Strength and Power, Anaerobic Power, and Urinary Testosterone: Epitestosterone Ratio in Young Males
European Food Safety Authority (2021)
Safety of Eurycoma longifolia root extract as a novel food
Evidence reviewed: October 2026
Evidence vs Hype explains scientific research for educational purposes and does not provide individual medical diagnosis or treatment.