Tongkat ali: Sharma et al., 2026

A 2026 critical review of androgen-modulating botanicals finds modest short-term testosterone increases in select populations for standardized Tongkat ali, ashwagandha, and fenugreek extracts — but evidence for meaningful clinical benefit is inconsistent, mechanism studies don't guarantee human outcomes, and most products lack the chemical characterization or trial design needed to establish real-world efficacy or safety.

Key takeaways

• Eurycoma longifolia (Tongkat ali), Withania somnifera (ashwagandha), and Trigonella foenum-graecum (fenugreek) show "limited-to-moderate" evidence for modest testosterone increases in selected male populations, particularly men with low baseline testosterone, aging symptoms, infertility, or stress. The review does not extend that evidence to healthy men with normal testosterone.
• Hormonal biomarker changes — like a small rise in total testosterone — do not automatically translate into clinical benefit like improved strength, libido, or mood; many trials measure hormones without tracking outcomes that matter.
• Preclinical mechanism studies (cell cultures, animal models, molecular docking) are hypothesis-generating, not proof of human efficacy; several botanicals with strong in vitro effects have failed in human trials.
• Evidence is preparation-specific: results from a standardized extract with published human data cannot be extrapolated to an uncharacterized powder or blend.
• This is a critical review, not a randomized trial — the authors appraised the quality of existing studies across multiple botanicals, separating strong from weak evidence by design, population, and endpoint.

The study

Sharma, Yakubu, and Pandey published this structured critical review in Pharmacological Research in 2026 (PubMed link). The authors reviewed human and mechanistic studies of botanicals marketed for androgen modulation, grading evidence separately for in silico predictions, biochemical target effects, hormonal biomarkers, clinical outcomes, extract chemistry, and safety. They included studies on Eurycoma longifolia (Tongkat ali), Withania somnifera (ashwagandha), Trigonella foenum-graecum (fenugreek), Mentha spicata (spearmint), curcumin, Salvia miltiorrhiza (red sage), and Serenoa repens (saw palmetto). The review was not a meta-analysis — no pooled effect sizes or statistical synthesis — but a narrative appraisal of study quality and population-specificity. The authors emphasized that evidence is preparation-dependent and cannot be generalized across uncharacterized products. They called for chemically defined extracts, population-specific trials, clinically meaningful endpoints, and active surveillance for hepatotoxicity, cardiovascular effects, contamination, and drug interactions.

How to read this study

What this review does well: The authors separate mechanistic plausibility from human efficacy — a distinction most supplement marketing ignores. They explicitly state that molecular docking (computer simulation of compound-protein binding) is hypothesis-generating, not confirmatory. They grade evidence by preparation, population, and endpoint, acknowledging that a standardized extract tested in infertile men doesn't tell us anything about an unstandardized powder in healthy men. They call out the saw palmetto example — plausible 5α-reductase inhibition in vitro, negative trials in humans — as a cautionary tale. This is the intellectual honesty rare in botanical reviews.

What this review is missing: It's a narrative critical review, not a systematic review with pre-registered inclusion criteria, risk-of-bias assessment tools, or pooled effect estimates. The authors chose which studies to include and how to weigh them — that's judgment, not reproducible algorithm. We don't see the raw data on sample sizes, effect sizes, or confidence intervals for each trial; we get their summary. The review also doesn't quantify how much testosterone increase is clinically meaningful — a 10% rise in total testosterone may be statistically significant but functionally irrelevant.

How I weight this review: I treat this as a high-quality orienting framework — it tells me where the strong evidence clusters (standardized extracts in specific populations) and where the gaps are (clinical outcomes, long-term safety, unstandardized products). It doesn't replace reading the underlying trials, but it's a sharp filter.

What they found

For Eurycoma longifolia (Tongkat ali), the review identified "limited-to-moderate evidence" for modest testosterone increases in men with low baseline testosterone, aging-related symptoms, infertility, or stress. The authors noted that evidence for "durable symptomatic or functional benefit" (outcomes such as strength, libido, mood, or body composition) is "less consistent and cannot be generalized across extracts." Studies measuring only hormonal biomarkers don't establish clinical benefit.

Withania somnifera (ashwagandha) and Trigonella foenum-graecum (fenugreek) showed similar patterns: modest testosterone increases in selected populations, inconsistent evidence for outcomes that matter. The review emphasized that its evidence grades are population-specific, so they don't automatically extend to men with normal baseline testosterone and no symptoms.

For androgen-suppressing botanicals, Mentha spicata (spearmint tea) showed short-term reductions in free or total testosterone in women with polycystic ovary syndrome or hirsutism in small studies, but objective improvement in hirsutism (the clinical outcome) was not demonstrated. Curcumin had preclinical evidence for effects on steroidogenic enzymes and androgen receptors but human studies predominantly reported metabolic outcomes or prostate-specific antigen levels, not systemic anti-androgenic efficacy.

Serenoa repens (saw palmetto) was cited as an example of mechanism-outcome disconnect: plausible 5α-reductase inhibition in biochemical assays, "largely negative trials" for benign prostatic hyperplasia. Dihydrotanshinone I from Salvia miltiorrhiza had biochemical evidence for CYP17A1 17,20-lyase inhibition but no controlled human trial establishing androgen-lowering efficacy.

The authors concluded that evidence grades are "preparation- and population-specific and do not apply to uncharacterized products."

What it means for the average man

If you're considering a botanical for testosterone support, this review clarifies two things: the evidence is modest and narrow, and the product matters as much as the ingredient. A standardized Tongkat ali extract with published human data in men with low testosterone or aging symptoms has limited but real support. A generic, uncharacterized powder with no published trials has none, even if it's the same plant.

The review also highlights the biomarker-outcome gap. A supplement might raise your total testosterone by 10-15%, but if that doesn't translate into improved strength, libido, energy, or body composition, the biomarker change is clinically meaningless. Many trials measure hormones and stop there. Look for studies that track outcomes you care about — gym performance, sexual function, mood, body fat percentage.

For men with normal testosterone and no symptoms, the evidence is weaker. The strongest signal is in men with low baseline testosterone, stress, infertility, or aging-related symptoms. If you're 28 with 650 ng/dL and no complaints, a Tongkat ali supplement is unlikely to do much.

The caveats

This is a narrative review, not a meta-analysis — the authors selected and interpreted studies, but we don't see pooled effect sizes or confidence intervals. The "limited-to-moderate" evidence grade is subjective. The review also doesn't define how much testosterone increase is clinically meaningful — a statistically significant rise may be too small to matter.

The authors emphasize preparation-specificity, but they don't detail which extracts in which trials showed the strongest effects. Readers would need to trace back to the original studies to see exact doses, extraction methods, and trial designs. The review calls for active surveillance for hepatotoxicity, cardiovascular effects, contamination, and drug interactions — a reminder that "natural" doesn't mean safe, and long-term safety data for most botanicals are limited.

Conflicting research exists for nearly every botanical reviewed. The saw palmetto example — plausible mechanism, negative trials — applies to many supplements. In vitro effects don't predict human outcomes.

Frequently asked questions

Related reading: Tongkat Ali at Clinical Doses: What 200mg vs 25mg Actually Does. Disclosure: Brookhaven makes Total Men's Package, which contains 500 mg tongkat ali extract (100:1), 400 mg fenugreek extract (50% saponins) and 300 mg ashwagandha whole herb (5% withanolides) per 7-capsule serving.

Sources

• Sharma K, Yakubu J, Pandey A. Analysis of androgen modulation by natural products. Pharmacological Research. 2026. PubMed.
• Henkel RR, et al. Tongkat ali as a potential herbal supplement for physically active male and female seniors—a pilot study. Phytotherapy Research. 2014;28(4):544-550. PubMed.

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.