Supplements
Tongkat Ali and Fadogia: One Has Human Trials, One Has a Rat Study
They get stacked in the same capsule and sold with the same promise. One of them has five randomized trials in men behind it. The other has rats.
Two herbs run the test-booster conversation right now. Tongkat ali and Fadogia agrestis. They get stacked together in the same capsule, sold with the same promise, and talked about on the same podcasts as if they carry the same weight of evidence.
They do not. One of them has real randomized trials in men. The other has a handful of rat studies from a single lab in Nigeria, and the most-cited one is 20 years old.
Here is the good news up front. If you want a plant that has actually been tested in humans for this, tongkat ali is the one, and the results are more encouraging than most of the supplement aisle. Here is the honest part. The effect is not TRT in a capsule, and the second herb is running on almost nothing. This is education, not medical advice.
Tongkat ali: the one with human trials
Tongkat ali is the root of Eurycoma longifolia, a Southeast Asian tree. It has been used in Malaysia for a long time, and unlike most traditional remedies somebody actually ran the trials.
Researchers pooled the randomized evidence in 2022. Nine studies made the systematic review and five randomized controlled trials made the meta-analysis. Total testosterone rose significantly in men taking it, with a standardized mean difference of 1.35 and a confidence interval running from 0.57 to 2.14 (Leisegang et al., 2022).
That is a real result. It is also a wide confidence interval built on five small trials, which is the polite way of saying the size of the effect is not nailed down. The authors were direct about it and said more research is needed before it goes into clinical practice.
Read the individual trials and the picture sharpens.
Healthy young men, two weeks
Thirty-two men averaging 24 years old took 600 mg a day or placebo for two weeks in a double-blind study. Total testosterone rose, free testosterone rose, and estradiol rose. Luteinizing hormone and follicle stimulating hormone did not move at all (Chan et al., 2021).
That last detail matters more than it looks. LH is the signal your pituitary sends to tell your testicles to make testosterone. If LH does not move, tongkat ali is not working the way people assume it does. The authors suggested the extra testosterone was coming through the adrenal pathway instead.
Stressed men and women, four weeks
Sixty-three adults screened for moderate stress took a standardized hot-water root extract or placebo for four weeks. Tension dropped 11 percent, anger 12 percent, and confusion 15 percent. Salivary cortisol fell 16 percent and salivary testosterone rose 37 percent (Talbott et al., 2013).
This is the study that gets quoted most, and the mood numbers are the interesting part. If tongkat ali does something useful for the average guy, the stress angle may be closer to the truth than the testosterone angle.
Men over 45 with low androgen symptoms
A six-month randomized, double-blind, placebo-controlled trial put 45 men averaging 47 years old into four groups: control, 200 mg tongkat ali, exercise, or both. Erectile function improved in both intervention arms, and the strongest results came from the men who trained and supplemented (Leitão et al., 2020).
The same trial tracked strength. Knee extension peak torque rose 14 percent in the training group and 17 percent in the training plus supplement group (Leitão et al., 2021).
Notice which variable is doing the heavy lifting. Training moved the numbers. The supplement rode along on top of it.
The older-adult pilot everyone quotes
Thirteen men and twelve women aged 57 to 72 took 400 mg a day for five weeks. Total and free testosterone rose, and so did handgrip strength (Henkel et al., 2013).
Worth knowing before you lean on it: this was a pilot study with no placebo group. Everybody got the supplement. That design cannot separate the herb from five weeks of being in a study and paying attention to your training.
What tongkat ali looks like when you add it all up
Doses in these trials ran from 200 to 600 mg a day of a standardized root extract, for two weeks to six months. Testosterone moved in most of them, more clearly in men who started lower. Mood and stress markers moved too. Strength results showed up mainly alongside training.
What it is not: a substitute for a prescription, a fix for a genuine hormone problem, or a reason to skip the boring levers. If your testosterone is low enough to cause symptoms, that is a conversation with a doctor and a blood draw, not a capsule off the internet.
What it might be: a reasonable thing to try for eight to twelve weeks if you are already training, sleeping, and eating like you mean it, and you want one more lever. Get a product that states the extract standardization on the label, because the trials used standardized extracts and a bag of unspecified root powder is not the same thing.
Fadogia agrestis: one rat study doing all the work
Now the other half of the stack.
Fadogia agrestis is a shrub used in West African traditional medicine. The entire testosterone reputation traces back to one study. Male albino rats got 18, 50, or 100 mg per kg of an aqueous stem extract for five days. Mounting and intromission frequency went up, and serum testosterone rose in a dose-dependent way (Yakubu et al., 2005).
That is it. That is the study behind the hype.
As of August 2026, a PubMed search for Fadogia agrestis returns ten records total. Several are plant chemistry papers about isolating glycosides. One is a survey of herbal markets in Ghana. Not one is a trial in humans. There is no dose in men, no duration in men, and no safety data in men.
The part that gets left out
The same lab that ran the aphrodisiac study kept going, and the follow-ups do not get quoted on podcasts.
Rats given the same doses for 28 days showed changes across testicular function markers that the authors described plainly as adverse effects on male rat testicular function. Recovery happened mainly at the lowest dose, 18 mg per kg (Yakubu et al., 2007).
A separate 28-day study looked at liver and kidney. Enzyme activity dropped inside the tissue and rose in the blood, and a marker of fat oxidation in the blood went up. The authors read that pattern as damage to the cell membranes of liver and kidney cells (Yakubu et al., 2009).
So the honest summary is this. The herb that supposedly raises testosterone in rats also appears to damage rat testicles, liver, and kidneys over four weeks at the doses that produced the effect. Nobody has checked what it does in a man over any length of time.
You may not even be getting the plant
There is one more problem. Researchers at the University of Mississippi built a method to measure Fadogia compounds and ran it on 17 dietary supplements that claimed to contain it. In five of them, the phenolic compounds were not detected at all (Avula et al., 2018).
Roughly one in three products tested had no measurable trace of the marker compounds it advertised. That is the state of quality control on an ingredient with zero human trials.
How to think about the two together
Tongkat ali has randomized, placebo-controlled human evidence, a plausible dose range, and effects that show up most clearly in stressed or lower-testosterone men. It is a fair thing to try with clear eyes.
Fadogia agrestis has one rodent study driving the whole market, follow-up rodent studies pointing at organ damage, no human data of any kind, and a real chance the capsule does not contain what the label says.
If you are taking a stacked product with both, you are paying for the tested ingredient and swallowing the untested one for free.
And whichever way you go, remember what actually moves testosterone in men who are not clinically low: sleep, body fat, training, and alcohol. Those four beat anything in a bottle, and they are free. If you are on any medication or have a liver, kidney, or hormone condition, talk to your prescriber before adding either herb.
The verdict
Tongkat ali earned its spot on the shelf. Five randomized trials pooled together show a real rise in total testosterone, the mood and stress data are genuinely interesting, and 200 to 600 mg a day of a standardized extract is a defensible thing to test on yourself for a few months.
Fadogia agrestis did not earn it. One rat study from 2005 built an entire product category, the same lab's follow-ups found organ damage in rats, no human has ever been studied, and a third of the products tested had no detectable trace of it.
Buy the one with the trials. Skip the one with the rats.
That is the verdict.
References
- Leisegang K, Finelli R, Sikka SC, Panner Selvam MK. Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials. Medicina (Kaunas). 2022. https://pubmed.ncbi.nlm.nih.gov/36013514/
- Chan KQ, Stewart C, Chester N, Hamzah SH, Yusof A. The effect of Eurycoma Longifolia on the regulation of reproductive hormones in young males. Andrologia. 2021. https://pubmed.ncbi.nlm.nih.gov/33559971/
- Talbott SM, Talbott JA, George A, Pugh M. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. J Int Soc Sports Nutr. 2013. https://pubmed.ncbi.nlm.nih.gov/23705671/
- Leitão AE, Vieira MCS, Pelegrini A, da Silva EL, Guimarães ACA. A 6-month, double-blind, placebo-controlled, randomized trial to evaluate the effect of Eurycoma longifolia (Tongkat Ali) and concurrent training on erectile function and testosterone levels in androgen deficiency of aging males (ADAM). Maturitas. 2021. https://pubmed.ncbi.nlm.nih.gov/33541567/
- Leitão AE, Vieira MCS, Gomes DA, et al. Exercise associated or not to the intake of Eurycoma longifolia improves strength and cardiorespiratory fitness in men with androgen deficiency. Complement Ther Clin Pract. 2021. https://pubmed.ncbi.nlm.nih.gov/33445146/
- Henkel RR, Wang R, Bassett SH, et al. Tongkat Ali as a potential herbal supplement for physically active male and female seniors: a pilot study. Phytother Res. 2014. https://pubmed.ncbi.nlm.nih.gov/23754792/
- Yakubu MT, Akanji MA, Oladiji AT. Aphrodisiac potentials of the aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem in male albino rats. Asian J Androl. 2005. https://pubmed.ncbi.nlm.nih.gov/16281088/
- Yakubu MT, Akanji MA, Oladiji AT. Effects of oral administration of aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem on some testicular function indices of male rats. J Ethnopharmacol. 2008. https://pubmed.ncbi.nlm.nih.gov/18023305/
- Yakubu MT, Oladiji AT, Akanji MA. Mode of cellular toxicity of aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem in male rat liver and kidney. Hum Exp Toxicol. 2009. https://pubmed.ncbi.nlm.nih.gov/19755438/
- Avula B, Bae JY, Raman V, et al. Quantification of Phenolic Compounds from Fadogia agrestis and Dietary Supplements using UHPLC-PDA-MS. Planta Med. 2019. https://pubmed.ncbi.nlm.nih.gov/30170324/
Common questions
Does tongkat ali actually raise testosterone?
In the pooled randomized evidence, yes. A 2022 systematic review and meta-analysis included nine studies, five of them randomized controlled trials, and found a significant increase in total testosterone with a standardized mean difference of 1.35 and a confidence interval from 0.57 to 2.14 (Leisegang, 2022). The effect is clearest in men who start on the lower end. The confidence interval is wide because the trials are small, and the authors said directly that more research is needed before clinical use.
What dose of tongkat ali was used in the studies?
Between 200 and 600 mg a day of a standardized root extract. A six-month randomized trial in men averaging 47 used 200 mg (Leitao, 2020). A two-week study in healthy young men used 600 mg (Chan, 2021). A pilot in adults aged 57 to 72 used 400 mg (Henkel, 2013). The trials used standardized extracts, so a product that states its standardization on the label is closer to what was actually tested than plain root powder.
Is Fadogia agrestis safe?
Nobody knows, because it has never been tested in humans. As of August 2026 a PubMed search returns ten records for Fadogia agrestis and none of them is a human trial. What does exist is rodent work from one lab. A 28-day study reported changes the authors described as adverse effects on male rat testicular function (Yakubu, 2007), and a second 28-day study found a pattern in the liver and kidney the authors read as cell membrane damage (Yakubu, 2009). Treat it as untested.
Where did the Fadogia testosterone claim come from?
A single 2005 study in male albino rats. Doses of 18, 50, and 100 mg per kg of an aqueous stem extract raised mounting and intromission frequency and increased serum testosterone in a dose-dependent way (Yakubu, 2005). That one rodent paper is the foundation of the entire product category. No human study has followed it.
Do Fadogia supplements even contain Fadogia?
Often not in measurable amounts. Researchers developed a method to quantify the plant's phenolic compounds and tested 17 dietary supplements that claimed to contain it. In five of the 17, the compounds were not detected at all (Avula, 2018). That is about one in three products with no measurable trace of the marker compounds on the label.
Should I take a stack with both herbs?
You are paying for one tested ingredient and swallowing an untested one alongside it. If you want to try the evidence-backed option, take tongkat ali on its own, from a product that states its extract standardization. And keep the free levers first: sleep, body fat, training, and alcohol move testosterone in men who are not clinically low more than anything in a bottle. If you take medication or have a liver, kidney, or hormone condition, talk to your prescriber before adding either one.
