Benefits
Testosterone support in men with low levels
In the one cited trial, 45 men with a diagnosed androgen deficiency of the aging male (average age 47) took Eurycoma longifolia extract 200 mg a day for 6 months. Total testosterone rose in the group that took the herb AND did a supervised exercise programme at the same time, so the herb alone was not shown to raise it. The trial tested the whole herb rather than purified eurycomanone, and there were only about 11 men per group. No meta-analysis is cited on this page.
Erectile function improvement
In the 6-month trial in 45 men with a diagnosed androgen deficiency of the aging male, erectile function improved in the group that took Eurycoma longifolia extract and followed a supervised exercise programme together. The trial did not show what the extract does on its own, it used the whole herb rather than purified eurycomanone, and each group held only about 11 men.
Cortisol and stress: not measured in the cited research
No study cited on this page measured cortisol, stress or mood. The single cited trial reported erectile function and testosterone only, so any claim about cortisol or the cortisol-to-testosterone ratio is unsupported here.
Aromatase inhibition (laboratory finding only)
Eurycomanone has been shown to block aromatase, the enzyme that converts testosterone to estradiol, in test tube work. That is a laboratory mechanism, not a human result: no study cited on this page measured estradiol or aromatase activity in people.
Muscle and exercise performance: not shown
No cited study measured muscle mass or exercise performance as a result of taking the supplement. The one cited trial actually had participants follow a supervised exercise programme alongside the herb, which means the exercise was part of the treatment rather than something the supplement improved.
Libido and sexual function
Tongkat ali root is used traditionally for libido. The one cited trial measured erectile function, which improved only in the group taking the herb alongside a supervised exercise programme, in 45 men with a diagnosed androgen deficiency. Libido itself was not a reported outcome, and there is no cited evidence in men with normal testosterone.
Sleep: no cited evidence
No study cited on this page looked at sleep. Sleep quality was not measured in the single cited trial, so there is nothing here to support a sleep benefit.
Mechanism of action
Aromatase inhibition (anti-estrogenic mechanism in men)
In laboratory studies eurycomanone blocks aromatase, the enzyme that converts testosterone to estradiol. This is a proposed mechanism from test tube work and has not been confirmed in the human research cited here. It should not be equated with prescription aromatase inhibitor medicines, which are drugs used under medical supervision for a different purpose.
Testosterone biosynthesis support (Leydig cells)
Laboratory work suggests eurycomanone acts on Leydig cells, the cells in the testes that make testosterone. This is a proposed mechanism from cell and animal research, not something measured in the human study cited on this page.
Cortisol / HPA axis modulation
A stress hormone mechanism is sometimes proposed for tongkat ali, but no study cited on this page measured cortisol or any stress hormone, so there is nothing here to confirm it.
Quassinoid bioactivity (distinct chemical class)
Quassinoids are a distinct chemical class with multiple biological activities. Eurycomanone is the primary bioactive among Tongkat Ali quassinoids; β-anhydroxonoeurycomalactone, eurycolactone, and other quassinoids contribute additional bioactivity.
9-hydroxycanthin-6-one alkaloid bioactivity
9-hydroxycanthin-6-one is an alkaloid in E. longifolia with additional bioactivity. Contributes to the multi-compound mechanism profile.
SHBG modulation
Sex hormone binding globulin (SHBG) binds testosterone in the blood, so lower SHBG would leave more free testosterone available. This is a proposed mechanism only: SHBG was not a reported outcome in the study cited on this page.
Clinical trials
Clinical evidence on Eurycomanone (Tongkat Ali Quassinoid) for the indications and outcomes described.
Clinical population described in trial publication.
This entry is not a clinical trial, and the review it refers to does not appear in this page's reference list, so its figures could not be verified and should not be relied on. The only verified study behind this page is the 6-month Maturitas trial described below.
Clinical evidence on Eurycomanone (Tongkat Ali Quassinoid) for the indications and outcomes described.
Clinical population described in trial publication.
Leitao AE and colleagues, Maturitas 2021 (PMID 33541567). A 6-month, double-blind, placebo-controlled randomized trial in 45 men, average age 47, with a diagnosed androgen deficiency of the aging male, split into four groups of roughly 11 men each. It tested Eurycoma longifolia extract 200 mg a day, the whole herb rather than purified eurycomanone. The improvement in erectile function and total testosterone came from the combination of the herb AND a concurrent supervised exercise programme, so the supplement was not shown to work by itself. The very small groups and the diagnosed patient population mean this result does not transfer to healthy men.
Clinical evidence on Eurycomanone (Tongkat Ali Quassinoid) for the indications and outcomes described.
76 patients with hypogonadism plus late-onset hypogonadism (LOH) on Physta®
This study does not appear in this page's reference list and could not be verified, so the 76-patient figure shown above should not be relied on. It also tested Physta, another company's branded tongkat ali extract, rather than purified eurycomanone.