THE SHORT VERSION: The evidence is real but modest, and it depends on who's taking it. The clearest results came from older men whose testosterone started below 300 ng/dL. In healthy men 30 to 55, testosterone didn't change significantly, but libido and sexual well-being did. Use tongkat ali to support healthy testosterone within the normal range,* on top of training and sleep. It isn't a hormone, and it isn't medical care.
Search "tongkat ali testosterone" and you'll find big promises. The trials tell a quieter, more useful story. We make a tongkat ali supplement, and we'd rather you take it with clear eyes. So here's every key study: who was in it, what dose they took, how long it ran, and what changed. Then what it means for you, and where training and sleep fit in.
What Does the Research Say About Tongkat Ali and Testosterone?
Modest support that depends on your starting point. Men whose testosterone started low saw the clearest changes. Healthy men with normal levels mostly didn't.
That's the honest summary of a 2022 meta-analysis. It combined five randomized controlled trials and found tongkat ali was associated with higher total testosterone, with a stronger effect in men who started below 300 ng/dL and a smaller one in men whose levels started in the normal range.[1] The best trial in healthy men aged 30 to 55 found no significant testosterone change at all.[2]
Why would age and starting point matter so much? Testosterone tends to drift down as men get older. Review authors estimate that men over 60 average roughly 40 to 50% lower levels than young men.[3] A man whose levels have drifted lower has more room for a change to show up on a lab report. A man already in a healthy range has less.
One more thing to know up front. Most of the positive human trials used one branded, standardized water extract, Physta®, and were funded or co-authored by its manufacturer.[2][4] That's common in herbal research and doesn't make the results wrong. It's a reason to read the details instead of the headlines, which is exactly what the next section does.
The Key Trials, Study by Study
Seven studies carry most of the weight. Here they are, from the earliest uncontrolled reports to the meta-analysis, with the details that change how you should read each one.
| Study | Who | Dose and duration | Testosterone result |
|---|---|---|---|
| 2012, uncontrolled | 76 men with a clinically diagnosed age-related testosterone decline | 200 mg/day, 1 month | Improved; no placebo group |
| 2014, pilot | 25 active men and women aged 57 to 72 | 400 mg/day, 5 weeks | Total and free testosterone higher; no placebo group |
| 2021, placebo-controlled | 105 men aged 50 to 70, starting below 300 ng/dL | 100 or 200 mg/day, 12 weeks | Total testosterone higher than placebo; free testosterone not different |
| 2012, placebo-controlled | 109 healthy men aged 30 to 55 | 300 mg/day, 12 weeks | No significant change |
| 2021, placebo-controlled | 45 men averaging 47, with a clinical diagnosis of age-related androgen decline | Daily extract plus training, 6 months | Best result when combined with training |
| 2024, placebo-controlled | 33 exercise-trained adults | 400 mg/day, 4 weeks | No change (salivary) |
| 2022, meta-analysis | 5 trials, 232 participants | Varied | Higher overall; strongest in men starting low; high variability |
The Early Uncontrolled Study (2012)
One of the first human reports gave 200 mg a day of a standardized extract to 76 men who had been clinically diagnosed with an age-related testosterone decline. After one month, testosterone and symptom-questionnaire scores improved significantly.[5] The catch: there was no placebo group, so there's no way to know how much of the change came from the extract. Read it as the starting gun, not the finish line.
The Active Seniors Pilot (2014)
Researchers gave 400 mg a day to 13 men and 12 women aged 57 to 72, all physically active, for five weeks. Total and free testosterone rose in both sexes, along with grip strength, and no side effects were reported.[6] Again, no placebo group, and just 25 people. It's useful for showing 400 mg a day was studied and tolerated, not as proof of effect.
The Largest Placebo-Controlled Trial (2021)
This is the most informative study. It randomized 105 men aged 50 to 70, all with total testosterone below 300 ng/dL, to 100 mg, 200 mg, or a placebo for 12 weeks. In the 200 mg group, average total testosterone went from about 200 to 225 ng/dL, versus 183 to 178 ng/dL on placebo. The 100 mg group moved from about 187 to 204 ng/dL.[4] Free testosterone did not differ significantly from placebo, and SHBG didn't change.[4]
The Healthy Men Trial (2012)
This is the study closest to most of our readers. It followed 109 healthy men aged 30 to 55 on 300 mg a day or placebo for 12 weeks. Testosterone did not change significantly. Sexual desire and sexual well-being scores, however, improved versus placebo.[2]
The Six-Month Training Trial (2021)
The longest trial in this set ran six months in 45 men, average age 47, with a clinical diagnosis of age-related androgen decline. It tested tongkat ali and a concurrent strength-and-cardio program, alone and together. The combination of tongkat ali plus training produced the most significant results for total testosterone.[7] Notably, it was government-funded, with no manufacturer funding reported.
The Null Trial in Trained Adults (2024)
Not every study is positive. Researchers gave 400 mg a day or a placebo to 33 exercise-trained men and women for four weeks and found no differences in salivary free testosterone, cortisol, body composition, or strength.[8] Four weeks is short, and saliva isn't blood, but it's an honest data point and we include it.
The Meta-Analysis (2022)
Pooling five randomized trials with 232 participants, the authors found tongkat ali was associated with higher total testosterone, more so in men starting below 300 ng/dL.[1] They also reported very high heterogeneity, meaning results varied widely from study to study, and signs of publication bias, meaning positive studies may be overrepresented in what's published.[1]
How Much Did Testosterone Change in the Studies?
Modestly. In the best-controlled trial, total testosterone moved about 25 ng/dL over 12 weeks in older men who started low, while placebo stayed flat.[4] In healthy men, it didn't move significantly.[2]
Put that in context. A shift from about 200 to 225 ng/dL is a real, statistically significant change in that population, and the same men reported better scores on aging-symptom and fatigue questionnaires.[4] It's also not the dramatic jump that marketing headlines imply. The NIH's LiverTox database describes the effect as mild rises in serum testosterone in some people, with free testosterone unchanged.[9]
The meta-analysis found a statistically significant pooled effect, but the spread between studies was wide enough that no single number describes what one man should expect.[1] That's why we don't quote a percentage, and why you should be skeptical of anyone who does.
The practical answer for a healthy man in his 30s or 40s: don't buy tongkat ali to chase a lab number. Use it to support healthy testosterone levels within the normal range* and the vitality and libido signals that showed up even when testosterone didn't change.[2] Results may vary.
How Might Tongkat Ali Work? The Proposed Mechanisms
Nobody has pinned it down. Researchers have proposed several pathways, and the human data only partly back them up.
Start with the chemistry. Tongkat ali root is rich in quassinoids, a family of bitter plant compounds. The most abundant, eurycomanone, is the one researchers point to most often when they discuss the root's effects.[10] Review authors affiliated with the extract's manufacturer have proposed that compounds in the root act on the body's hormone-production pathways, drawing largely on lab and animal research.[3] Those are hypotheses, not settled science.
The stress-hormone idea: cortisol, your main stress hormone, fell in two trials, one in stressed adults and one in older men.[4][11] The thinking is that a calmer stress-hormone profile leaves a better environment for healthy testosterone. A 4-week trial in trained adults found no cortisol change, though.[8]
The SHBG idea: SHBG, sex hormone-binding globulin, is a blood protein that holds testosterone so tissues can't use it. A popular claim says tongkat ali lowers SHBG and "frees" testosterone. In the largest placebo-controlled trial, SHBG didn't change and free testosterone wasn't different from placebo.[4] In the small seniors pilot, SHBG fell in the women.[6]
Bottom line: the mechanism story is still being written. The outcomes in controlled trials matter more than the theories, and those outcomes are the ones we've laid out above.
What Does "Within the Normal Range" Mean, and Why Do We Say It?
It means support for the healthy testosterone levels your body already makes. Not pushing levels past normal, and not fixing a medical condition.
A testosterone level that a doctor flags as clinically below normal is a medical diagnosis, made with blood tests. A dietary supplement can't legally claim to address a disease. The FDA is clear that a product marketed to address a specific disease is regulated as a drug, not a supplement.[12] So every testosterone statement we make carries "within the normal range." It isn't fine print. It's the line between a supplement and a drug.
It's also the honest reading of the data. In the trial of healthy men aged 30 to 55, testosterone stayed within the normal range and didn't change significantly, while sexual well-being improved.[2] The bigger testosterone shifts came from older men whose levels started below 300 ng/dL, a population we describe but never position tongkat ali as a fix for.[1][4]
So when you see us write that Prime Labs Tongkat Ali Plus supports healthy testosterone levels within the normal range,* that's the claim, all of it. If anyone promises more, ask what population their study used.
Does Tongkat Ali Affect Stress and Mood?
Possibly. One small trial showed a promising stress-hormone and mood signal, and it's worth understanding because stress and testosterone are closely linked.
In a 4-week placebo-controlled trial, 63 moderately stressed adults took 200 mg a day of a standardized extract. Salivary cortisol was lower than placebo, and mood scores improved for tension (11%), anger (12%), and confusion (15%).[11] Cortisol also fell over 12 weeks in the 200 mg arm of the large trial in older men.[4]
The limits: the stress trial pooled men and women, measured hormones in saliva rather than blood, and ran just four weeks.[11] The 2024 trial in trained adults found no mood or cortisol change.[8] Our grade is preliminary. Count stress support as a possible bonus, and keep doing the things with stronger evidence: sleep, training, and time away from the grind.
What Tongkat Ali Won't Do
Tongkat ali isn't a hormone, and it isn't a replacement for medical care. Know the boundaries before you start.
It isn't a hormone. Tongkat ali is a plant root. It contains no testosterone, and Prime Labs Tongkat Ali Plus contains no synthetic hormones.
It doesn't replace a doctor. If you're worried about your hormone levels, or you're dealing with persistent fatigue, low drive, or mood changes, get tested by a doctor. Don't self-diagnose with a supplement.
It isn't instant. Trials measured results after 4 to 12 weeks of daily use, and six months in one trial.[4][7][11] Results may vary.
It doesn't replace training. The six-month trial got its best results when tongkat ali was paired with exercise.[7]
It hasn't been studied for everything. We found no human research on tongkat ali and DHT or hair, so we don't make claims either way.
Long-term safety also hasn't been established beyond the trial periods, which is part of why we keep our claims to what the trials measured.[9] For the full safety picture, read Is Tongkat Ali Safe? Side Effects, Tolerability & How to Take It Right.
Who Sees the Most Benefit?
Older men whose levels have drifted lower saw the clearest testosterone changes. Healthy men 30 to 55 saw their gains in libido and well-being instead.
Men 50 and older: the strongest testosterone results in the research came from men aged 50 to 70.[1][4]
Healthy men 30 to 55: testosterone didn't change significantly, but sexual desire and sexual well-being improved versus placebo.[2] For this group, tongkat ali supports male vitality and libido.*
Men who train: in the six-month trial, the best result came from tongkat ali combined with a structured training program.[7]
If you're not sure where you sit, a blood test from your doctor will tell you more than any article. For a broader look at every benefit, read Tongkat Ali Benefits for Men: What the Evidence Supports.
Why Training and Sleep Still Do the Heavy Lifting
Tongkat ali works on top of the basics, not instead of them. The longest trial in the research made that point for us.
In the six-month trial, men who combined tongkat ali with three training sessions a week got the strongest results.[7] That's the pattern we'd expect. Training sends the signal. Recovery lets your body answer it. A supplement supports the process; it doesn't run it.
Lift consistently. Three structured sessions a week matches what the six-month trial used.[7]
Take tongkat ali daily. One two-capsule serving, every day, at a time you'll remember. Trials used 100 to 400 mg a day of a standardized extract, given daily, and none compared times of day.[2][4] See Tongkat Ali Dosage: How Much Per Day, and What "100:1" Means.
Add creatine for strength. Creatine has some of the deepest evidence in sports nutrition. Start with our creatine guide.
Protect your sleep. Recovery happens at night. Guard a consistent bedtime like a training session you don't skip.
Give it 12 weeks. That's the common endpoint in the trials. Results may vary. More in How Long Does Tongkat Ali Take to Work, and Should You Cycle It?
Worth knowing: the trials above used standardized water extracts, mostly Physta®. Prime Labs Tongkat Ali Plus uses a 100:1 tongkat ali extract at 400 mg per serving. 100:1 ratio describes concentration, not a standardized potency measure.
