What Does Tongkat Ali Actually Do?
Tongkat Ali (Eurycoma longifolia) is a Southeast Asian botanical that has been used for centuries in traditional medicine. Over the past two decades, a growing body of clinical research has validated several of its traditional uses, particularly around hormonal balance, stress resilience, and male vitality. Below, we break down the benefits that have meaningful scientific support.
Testosterone Optimization
The most widely studied benefit of Tongkat Ali is its effect on testosterone levels, but the mechanism is often misunderstood. Tongkat Ali does not artificially inflate testosterone the way exogenous hormones do. Instead, research suggests it works by:
- Reducing sex hormone-binding globulin (SHBG), which frees up more bioavailable testosterone already present in the body.
- Supporting the hypothalamic-pituitary-gonadal (HPG) axis, helping the body’s own signaling pathways function more efficiently.
- Lowering cortisol, which can suppress testosterone production when chronically elevated.
A 2022 systematic review and meta-analysis by Leisegang et al. published in Medicina concluded that Eurycoma longifolia supplementation significantly improved serum total testosterone in men across multiple clinical trials, along with improvements in physical performance and quality of life (Leisegang et al., 2022). An earlier randomized trial found that 200 mg/day of standardized Tongkat Ali extract significantly increased total and free testosterone in men with low baseline levels over a 12-week period (Henkel et al., 2014). A separate study reported improvements in testosterone levels and semen parameters in men experiencing late-onset hypogonadism (Tambi et al., 2012).
A 2024 systematic review examining whether “testosterone boosters” genuinely raise serum testosterone found Tongkat Ali to be among the limited number of supplements with meaningful clinical evidence supporting testosterone modulation (Morgado et al., 2024).
The testosterone-supporting effect is most pronounced in men who have suboptimal or borderline-low levels. Healthy young men with already-normal testosterone may see modest or negligible changes.
Cortisol Reduction and Stress Resilience
One of the strongest and most consistent findings in the Tongkat Ali literature involves cortisol. A well-cited study by Talbott et al. (2013) published in the Journal of the International Society of Sports Nutrition examined moderately stressed adults and found that four weeks of supplementation with 200 mg/day of a standardized extract resulted in:
- A 16% reduction in salivary cortisol compared to placebo.
- A 37% improvement in the testosterone-to-cortisol ratio, a marker often used to assess anabolic status and recovery capacity.
- Significant improvements in self-reported tension, anger, and confusion on the Profile of Mood States (POMS) questionnaire.
This cortisol-lowering effect may explain many of the downstream benefits attributed to Tongkat Ali, including better sleep quality, improved mood, and enhanced recovery from exercise.
Athletic Performance and Recovery
Several studies have investigated Tongkat Ali in the context of exercise performance. While it is not a stimulant and should not be expected to produce acute performance boosts, the research suggests benefits that accumulate over weeks of consistent use:
- Improved strength outcomes: A pilot study in physically active seniors found improvements in muscular force after five weeks of supplementation (Henkel et al., 2014).
- Better recovery markers: The cortisol-lowering effect may help shift the body toward a more anabolic (recovery-promoting) state after training, supporting adaptation and reducing overtraining risk.
The performance benefits are likely most relevant for individuals under chronic physical or psychological stress, where elevated cortisol may be impairing recovery and adaptation.
Body Composition: Lean Mass and Fat Loss
Changes in body composition are a logical downstream effect of improved testosterone-to-cortisol ratios. While dedicated body composition trials are limited, the existing evidence is suggestive. A multicentre randomized trial by Chinnappan et al. (2021) found that a standardized Tongkat Ali extract improved testosterone levels and quality of life markers in aging men, with testosterone normalization supporting lean body mass maintenance (Chinnappan et al., 2021).
These effects are modest and should be viewed as supportive rather than transformative. Tongkat Ali is not a replacement for proper training and nutrition, but it may provide a meaningful edge when those foundations are in place.
Sexual Health and Libido
Traditional use of Tongkat Ali has long centered on male sexual health, and modern research has provided some validation. A 12-week randomized trial found significant improvements in sexual function scores (measured via the International Index of Erectile Function, a validated questionnaire) in men supplementing with 200 mg/day of Tongkat Ali extract (Ismail et al., 2012). Improvements in libido and sexual well-being have been reported across multiple studies, likely mediated by the combined effects of increased free testosterone and reduced cortisol.
While Tongkat Ali is not a pharmaceutical treatment, the evidence supports its use as a natural approach to supporting healthy sexual function and vitality, particularly in men experiencing age-related changes in hormone levels.
Sperm Quality and Male Fertility
A notable area of research involves Tongkat Ali’s effects on semen parameters. Tambi et al. (2012) conducted a study in men with idiopathic infertility and found that nine months of supplementation with 200 mg/day resulted in significant improvements in sperm concentration, motility, and morphology (Tambi et al., 2012). These findings are encouraging, though larger confirmatory studies are needed. The mechanism likely involves both hormonal optimization and the antioxidant properties of certain quassinoid compounds found in the root.
Benefits for Women
While most research has focused on men, a 2023 randomized, double-blind, placebo-controlled trial published in BMJ Open evaluated Tongkat Ali in perimenopausal and postmenopausal women. The study found significant improvements in well-being, energy levels, and sexual function parameters in women receiving the standardized extract, suggesting the adaptogenic and quality-of-life benefits extend beyond male populations (Muniandy et al., 2023).
The cortisol-reducing properties demonstrated by Talbott et al. (2013) also included female participants, supporting the idea that Tongkat Ali’s stress-modulating effects are not sex-specific (Talbott et al., 2013).
Mood and Well-Being
Beyond the hormonal and physical benefits, Tongkat Ali appears to have a positive effect on subjective well-being. The Talbott et al. (2013) study reported improvements across multiple mood subscales, including reduced tension, anger, and confusion. These effects are consistent with the observed reduction in cortisol. Chronic stress is a well-established driver of mood disturbance.
Potential Immune Support
Preliminary evidence suggests that Tongkat Ali may support immune function. A study in middle-aged men and women found that four weeks of supplementation improved various immune parameters, including T-cell counts and immunoglobulin levels (George et al., 2016). While this is an emerging area of research and not yet a primary reason to supplement, it adds to the broader profile of Tongkat Ali as a general adaptogen.
The Bottom Line
Tongkat Ali has a legitimate and growing body of clinical evidence supporting its use for testosterone optimization, cortisol reduction, stress resilience, and male vitality. The strongest evidence exists for men with suboptimal hormone levels or those under chronic stress. Benefits appear to build over several weeks of consistent use, and the compound works best as part of a foundation that includes proper sleep, nutrition, and training.