Does Tongkat Ali Really Increase Testosterone? (A Look at the Evidence)

Overview: Although Tongkat Ali can certainly be helpful it is not on my ‘must have’ list of natural testosterone boosters. It is helpful used in conjunction with other ingredients but is neither going to be that strong nor very helpful on it’s own.


Tongkat Ali (botanical name – Eurycoma longifolia) is a medicinal plant from Malaysia and Thailand used extensively for its aphrodisiac properties. Generally, an aqueous extract of this flowering plant is used as herbal medicine and traditionally it is consumed along with coffee decoction. Quassinoids in the root extract have been identified as the biologically active components of the plant. Studies on animal models like rat and rabbit have demonstrated its positive influence on sperm quality and hormonal levels.

Toxicology studies suggest that 1.2 gm per day dose in adults should not show any side effects. Tongkat Ali and testosterone supplements are being marketed with claims to improve sports performance, libido, muscle strength, weight loss – most of the phenomenon associated with testosterone levels. The few key scientific studies on the effect of Tongkat Ali extract on human and animal models are summarized in this article.

Tongkat Ali extract enhances testosterone levels and improves sexual performance

Study: Udani recruited 12 healthy males (aged between 40-65 years) to evaluate the effect of a 200mg per day supplement of Tongkat Ali along with 100mg per day of an antioxidant. The duration of the study was 12 weeks and at the end of study serum hormone levels were measured and various sexual parameters were noted. In addition, authors collected data at two earlier time points of 3 and 6 weeks during the study.

Result: 12-week supplementation of Tongkat Ali extract improved all sexual parameters and caused a general feeling of well being. Serum total testosterone levels increased significantly as compared to the placebo or control group. Liver and kidney function tests revealed no harmful effect of the extract on the critical organs.

Conclusion: Tongkat Ali extract helps improve sexual function and elevate total testosterone levels.


Tongkat Ali root extract enhances testosterone and controls stress hormones

Study: A four-week clinical study was taken up on 63 human subjects (both male and female) under moderate stress to evaluate the effect of aqueous root extract on the hormonal profile. All the subjects were given 200mg extract per day for four weeks and levels of hormones like testosterone and cortisol were quantified before and after the study. Investigators estimated salivary testosterone and cortisol levels. In addition, all the subjects answered a questionnaire about their general mood, fatigue, and anxiety.

Result: Salivary testosterone levels improved in all the subjects whereas the levels of stress hormone ‘cortisol ’decreased. A clear conclusion about the mood change parameters cannot be drawn as only subjects responded positively.

Conclusion: Tongkat Ali extract increases testosterone levels.


Tongkat Ali extract improves testosterone and muscle strength in elderly human subjects

Study: Thirteen physically active elderly males and 12 females (age range between 54-72 years) were given 500mg of Tongkat Ali extract per day for 5 weeks. Blood parameters like hematocrit value and levels of hormones like testosterone, cortisol, and sex hormone binding globulin were estimated before and after the study. Muscle grip was also tested on all the subjects prior to starting supplements and after completing the study.

Results: 5 weeks of supplements led to a significant increase in total and free testosterone levels in both the male and female subjects. Hematocrit value and blood count increased slightly in males and muscle strength improved both for females and males.

Conclusion: Tongkat Ali extract can help enhance testosterone levels and muscle strength in elderly people.


Tongkat Ali extract improves aging male symptoms and increases testosterone levels

Study: Tambi and co-workers analyzed 76 patients with late-onset hypogonadism and supplemented 200mg extract per day for 5 weeks. Testosterone levels and aging male symptoms were collected before and after the study.

Result: Testosterone levels improved significantly in all the subjects. Approximately 90% of the patients had normal values of aging male symptoms after the supplementation as compared to 35% before the study.

Conclusion: Tongkat Ali extract improves testosterone levels in individuals with late-onset hypogonadism.


Tongkat Ali extract improves semen parameters; no effect on testosterone levels

Study: 109 healthy males ( age range 30-55 years) were given 300 mg Tongkat Ali extract per day for 12 weeks. At the end of study hormone levels were quantified and semen analysis was conducted. The sexual well being was evaluated on the basis of an international index for erectile function and sexual health questionnaires.

Result: At the end of 12 weeks of supplementation subjects show significantly improved in sexual well being scores, increase in sperm motility (reached 44%) and an increase in semen volume. The testosterone levels did not increase significantly.

Conclusion: Tongkat Ali extract improves sexual function in males but has no effect on testosterone levels.


Tongkat Ali extract improves spermatogenesis in rats

Study: Several fractions of root extracts of Tongkat Ali were separated by chromatography. The fraction with most potent bioactive compound quassinoid and a normal aqueous extract were used for studies on rats. The study spanned 15 weeks and rats were orally administered 25mg per kg body weight of quassinoid fraction and another group was given 250 mg per kg body weight of the aqueous extract. At the end of study testosterone levels were estimated and spermatogenesis was microscopically evaluated.

Results: Chemically both the fractions were similar. The rate of spermatogenesis significantly improved in treated rats as compared to control. The levels of serum testosterone, luteinizing hormone and follicle stimulating hormone increased significantly.

Conclusion: The chemically active component “quassinoids” in Tongkat Ali extract helps in improving sperm synthesis and increasing testosterone levels.


Quassinoids in Tongkat Ali extract arrest the bioconversion of testosterone

Study: Rat testicular cells were isolated and grown in vitro in Petri dishes. These cells were treated with extract at varying concentrations and combinations with drugs inhibiting specific enzymes that bio converts testosterone to dihydrotestosterone.

Result: Tongkat Ali extract improved the testosterone levels in the cells that were treated with extract alone and not any other drug. In the cells that were incubated with extract along with the inhibitory drugs; no significant increase in testosterone levels was observed. The results provide evidence that Tongkat Ali extract works via inhibiting the enzymes that are responsible for bioconversion of testosterone. Hence it ultimately results in increased testosterone levels.

Conclusion: Quassinoids in Tongkat Ali extract act by inhibiting the activity of enzymes that are responsible for bioconversion of testosterone.


Toxicity studies in rats

Study: Various doses with different time courses were administered to Wistar rats and the effect was noted in terms of mutagenicity, genotoxicity, body weight, hematological parameters, serum biochemistry and urine analysis. Treatments can be broadly classified into three categories: high dose treatments for the short-term, lower doses for 4 and 13 weeks. Overall the dosage range was in between 0.6 gm per kg to 2gm per kg of body weight.

Result: Tongkat Ali extract did not cause any adverse effects on biochemical parameters, urine parameters and on tissues. Few beneficial changes like reduction in prothrombin time and partial thromboplastin time were observed.

Conclusion: Tongkat Ali extract is safe and extrapolating the rat data, authors concluded that 1.2 gm per day can be well tolerated by a human adult.


Tongkat Ali root extracts that mainly constitute quassinoids has been found safe in animal models and human clinical studies. Its role in enhancing testosterone levels and semen parameters appears very promising as shown by the scientific studies. These supplements at a dose of 200-300 mg per day have been shown effective in addressing the symptoms of ageing among males.