Tongkat ali

What is tongkat ali?

Tongkat ali (Eurycoma longifolia), also called longjack, is a shrub native to Malaysia, Indonesia and nearby countries. Its root has a long history in traditional medicine as a tonic for male vitality, fatigue and fever. Supplements typically use water extracts standardized to marker compounds such as eurycomanone, sometimes labeled with ratios such as 100:1 or 200:1.

What the research says

A 2022 systematic review and meta-analysis looked at randomized trials of tongkat ali used on its own. Nine studies were reviewed and five were pooled; tongkat ali was associated with a significant increase in total testosterone, an effect that held in the subgroup of men with low testosterone (hypogonadism). The authors called it a possible option but said more research is required before clinical use (Leisegang et al., 2022).

A separate systematic review of testosterone booster supplements, which found that most products fail to raise testosterone, classified Eurycoma longifolia as possibly effective for men with late-onset hypogonadism and for healthy men (Morgado et al., 2024). The trials are generally small and short, and several used proprietary extracts from manufacturers.

No clinical trials have tested tongkat ali for prostate size, urinary flow or prostate cell health. Raising testosterone is not a prostate benefit in itself; testosterone is converted to DHT, which drives prostate growth, and men with prostate cancer are often treated by lowering testosterone. That is why men with prostate concerns should talk to their doctor before using any product designed to increase testosterone.

How it’s used in supplements

Tongkat ali appears in testosterone, libido and sports products. Trials have commonly used 200 to 400 mg of standardized extract daily; 100 mg in a blend is at the low end, and the label usually does not state the standardization.

Short-term use appeared well tolerated in trials. Possible side effects include sleep disturbance, restlessness and irritability. Quality varies, and herbal products from some regions have been found to contain heavy metals or undeclared drugs, so third-party testing is useful. Avoid tongkat ali in pregnancy and breastfeeding, and consult a doctor if you have prostate cancer, a hormone-sensitive condition, heart disease, or take blood sugar or blood pressure medication.

The bottom line: tongkat ali is one of the few herbal testosterone boosters with some supportive randomized data, but the trials are small, often industry-linked, and focused on hormone levels rather than how men feel or function. It has no demonstrated prostate benefit. For men worried about low energy or low libido, a blood test and a conversation with a doctor are a better starting point, since symptoms of low testosterone overlap with sleep problems, depression, thyroid disease and medication side effects.