Tongkat Ali vs. Tribulus for Male Fertility: What the Small Trials Actually Measured

Short answer: tongkat ali has the better evidence for raising testosterone, while tribulus has more studies that actually measured sperm. Neither has good evidence that it increases pregnancy or live birth rates. The trials are small, the designs are uneven, and these herbs are sold in a product category where adulteration is a documented problem. If you're trying to conceive, treat both as optional experiments to discuss with a clinician, not as fixes.

The most common mistake is assuming that a supplement which nudges testosterone will help fertility. Testosterone and sperm production are linked, but they aren't the same thing, and more testosterone in the bloodstream doesn't automatically mean more or better sperm. That distinction is the key to reading this research.

The comparison at a glance

Tongkat ali: a testosterone story, not a sperm story

Tongkat ali is a root extract from a Southeast Asian shrub. A 2022 systematic review and meta-analysis by Leisegang and colleagues searched six databases for clinical trials. It included nine studies in the review and pooled five randomized trials. The pooled result showed a statistically significant increase in total testosterone, with improvements reported mostly in healthy volunteers and in men with hypogonadism (low testosterone). The authors called the results promising but said more research is needed before clinical use.

Look at what's missing from that summary: sperm. The review's abstract doesn't report semen or fertility outcomes. So the strongest evidence for tongkat ali answers a different question from the one couples trying to conceive are asking.

Why higher testosterone isn't the goal

Sperm production depends on testosterone inside the testes, which is regulated by signals from the brain (LH and FSH). Blood testosterone is only a partial window into that system. The clearest illustration runs the other way: prescription testosterone therapy suppresses those brain signals and can shut down sperm production, which is why men trying to conceive are generally steered away from it. howtohaveababy.com explains this in its piece on the testosterone and fertility myth.

A modest rise in blood testosterone from an herb isn't the same as taking testosterone, and there's no evidence that tongkat ali suppresses sperm in the same way. The point is narrower: a "T-booster" label tells you nothing about fertility.

Tribulus: sperm outcomes, weak designs

Tribulus terrestris is a flowering plant used in Ayurvedic and traditional Chinese medicine. Here the research is pointed more directly at fertility. A systematic review by Sanagoo and colleagues looked specifically at sperm parameters in men with idiopathic infertility, meaning no identified cause. It screened thousands of records and included seven studies. Six reported improvement in some or all sperm parameters (count, motility, morphology). One quasi-experimental study without a control group found no benefit.

That sounds encouraging until you read the fine print:

• Study designs were mixed. The review included clinical trials and quasi-experimental studies, and at least one had no control arm. Without a comparison group, normal week-to-week variation in semen results can look like improvement.
• Semen parameters aren't pregnancies. The abstract doesn't report pregnancy or live-birth outcomes.
• No formal quality grading is reported in the abstract. Six positive small studies can still add up to weak evidence.

The lesson from zinc applies here too. Small positive trials often fail to hold up when a large, well-run trial tests the same idea. That's what happened with zinc and folic acid; see our breakdown of zinc after the FAZST trial.

The product-quality problem

Even if an herb works, the bottle you buy may not contain what the label says, or may contain things the label doesn't mention. Products marketed for male performance and "vitality" are a known trouble spot.

That doesn't mean every tongkat ali product is adulterated. It does mean the category deserves caution, especially products sold for sexual performance, products making dramatic claims, and anything bought from an unknown seller. Our guide to third-party testing for fertility supplements explains what seals like USP and NSF verify and what they don't.

Label red flags

• "Works like Viagra," "instant results," or "clinically proven" with no study named.
• A proprietary blend that hides how much of each herb you're getting.
• No standardization statement for the extract (for tongkat ali, labels often name the extract ratio or a marker compound).
• No lot number or manufacturer contact details.
• Marketed for both "testosterone" and "sexual enhancement" at the same time.

How to decide: a short checklist

1. Get a semen analysis first. Without a baseline, you can't tell whether anything helped. Sperm take about three months to develop, so judge any change after that window.
2. Be clear about your goal. If it's fertility, testosterone-focused products are aimed at the wrong target. If a clinician has found low testosterone, that's a separate conversation, and it should include fertility-preserving options.
3. Pick one product, not a stack. Taking tongkat ali, tribulus, maca and shilajit together makes it impossible to know what's doing what, and multiplies the quality risk.
4. Prefer third-party-tested products from sellers you can trace.
5. Tell your clinician, especially if you take blood pressure, diabetes or heart medications.
6. Don't let supplements delay an evaluation. ASRM recommends an infertility evaluation after 12 months of trying when the female partner is under 35, or 6 months when she's 35 or older. conceiveguide.com covers the male infertility treatment options that evaluation can open up.

What tends to matter more

For most men, the basics outweigh any herb: not smoking, moderating alcohol, keeping weight in a healthy range, keeping the testicles cool, and getting enough sleep. fertilestart.com's male fertility lifestyle guide pulls those together, and our male fertility hub links the supplement research we've reviewed.

Supplements don't treat infertility. Tongkat ali and tribulus haven't been shown to improve pregnancy rates. Clear either one with your clinician before you start.

Sources

• Leisegang K, Finelli R, Sikka SC, et al. Eurycoma longifolia (Jack) improves serum total testosterone in men: a systematic review and meta-analysis of clinical trials. Medicina (Kaunas). 2022;58(8):1047. PubMed 36013514
• Sanagoo S, Sadeghzadeh Oskouei B, Gassab Abdollahi N, et al. Effect of Tribulus terrestris L. on sperm parameters in men with idiopathic infertility: a systematic review. Complement Ther Med. 2019;42:95–103. PubMed 30670288
• FDA. Warning letter to HIS Enterprise Inc dba Adam's Secret USA, LLC (646494), January 10, 2023. fda.gov
• ASRM Practice Committee. Definition of infertility: a committee opinion (2023). asrm.org (PDF)