Tongkat Ali: What the Testosterone Research Shows
Tongkat ali (Eurycoma longifolia) is a Southeast Asian root used in Malaysia and Indonesia, and a staple of men's-health ads. Here is the evidence, including the parts the ads leave out.
Quick Summary
Small trials found higher total testosterone, clearest in men with low levels. That is not a promise about energy, libido, or performance.
The 2022 meta-analysis
| Feature | What the paper reports |
|---|---|
| What was pooled | 5 randomized trials, 232 men, inside a review of 9 studies. |
| Pooled effect | SMD 1.352 (95% CI 0.565 to 2.138), p=0.001, on total testosterone. |
| Who it was clearest in | The hypogonadism subgroup. This is not a result we are extending to men with normal levels. |
| Extract | Physta in 7 of 9 studies, 100 to 600 mg a day. LJ100 does not appear in the paper. |
Leisegang et al., Medicina, 2022. PMC9415500, PMID 36013514. Studies were small. A standardized mean difference this large, from small trials of mostly one extract, is not the same as a proven clinical effect.
What this is not
It is not a substitute for a medical evaluation of low testosterone. Fatigue and low libido have many causes. See a doctor.
A few small trials look at stress hormones or sperm measures. They are not enough to make a claim. Fadogia agrestis has essentially no human efficacy or safety trials. We do not recommend it, including as a stack.
Side effects
The trials reported few adverse events, mostly mild: sleep disturbance, restlessness, and stomach upset. Safety past about 12 weeks is not well studied.
Ask a clinician first with prostate or other hormone-sensitive conditions, heart, liver, or kidney disease, diabetes medication, or testosterone therapy. Not for pregnancy, breastfeeding, or anyone under 18.
Extract types
Physta is the water extract used in most of the studies in the 2022 review. LJ100 is a patented extract some brands sell. They are not the same name, and the paper does not mention LJ100.
A 100:1 or 200:1 ratio means how much raw root went into the extract. It is not a potency guarantee. Prefer a stated marker, such as eurycomanone, plus a certificate you can open.
Labels we could read
| Feature | What the page states | Price |
|---|---|---|
| Double Wood LJ100 | Patented LJ100 extract. Milligrams not in the description. Every batch tested by ISO/IEC 17025 labs, COAs published, brand-stated. We did not open a certificate. This is not the Physta extract from the meta-analysis. | $39.95 |
| Double Wood 200:1 blend | 1,000 mg of a 200:1 extract plus 20 mg of tribulus. The 200:1 line is a raw-root ratio, not proof the serving is 200 times stronger. Tribulus evidence in humans is weak. Treat this as a blend. | $29.95 |
Who this is for
Who Might Like This
- ✓Adult men with lab-confirmed low testosterone, discussing it with their doctor, who understand the trials are small.
Who Should Consider Alternatives
- ×Men with normal testosterone. The paper's confirmed subgroup was hypogonadism.
- ×Prostate conditions, hormone therapy, heart, liver, or kidney disease, or under 18.
Our verdict
Tongkat ali has a real but limited signal: small trials, mostly one extract called Physta, with higher total testosterone that the authors confirmed in men with low levels. If you try a product, do not assume LJ100 is what those trials used. Get levels checked first.
Related guides
Sources
How we checked
On October 21, 2026, we re-opened PMC9415500. It pooled 5 randomized trials (232 men) from a review of 9 studies. SMD was 1.352 (95% CI 0.565 to 2.138). The increase was confirmed in the hypogonadism subgroup. Physta was the extract in 7 of 9 studies, at 100 to 600 mg a day. A search of the page for LJ100 returned no hits.
Double Wood LJ100 was $39.95 with no milligram dose in the description, plus a brand-stated ISO/IEC 17025 line. The 200:1 product was $29.95 and stated 1,000 mg of extract plus 20 mg tribulus. Lost Empire's dose and price were not re-fetched, so that row is omitted.
Frequently Asked Questions
A 2022 meta-analysis of 5 randomized trials found higher total testosterone, confirmed in men with hypogonadism. The studies were small and mostly used one commercial extract, Physta.
Mostly mild: restlessness, trouble sleeping, and stomach upset. Safety past about 12 weeks is not well studied.
The studies in that review used about 100 to 600 mg a day of a water extract. Follow a label that states its milligrams. Double Wood's LJ100 page did not.
No. The 2022 review names Physta in seven of nine studies and does not mention LJ100.
Fadogia has essentially no human safety or efficacy trials. We do not recommend it.
Both have small testosterone trials. Ashwagandha has more evidence on stress and sleep scores. See the ashwagandha guide.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Evident does not sell any of these products and uses no affiliate links.