Fenugreek (Trigonella foenum-graecum) is a clover-like herb whose seeds smell and taste like maple syrup. The seeds have a long history as a spice and a traditional remedy, and today they are sold as dietary supplements for blood sugar, breast milk supply and, in sports nutrition, as a “testosterone booster” (NCCIH; Yang et al., Front Nutr 2026).
The most important fact for this library: fenugreek is not a hormone and is not approved as a drug for any use. A 2026 meta-analysis of randomized placebo-controlled trials in men found at most a small rise in total testosterone, no reliable change in free testosterone, and rated the certainty of that evidence as very low (Yang et al., Front Nutr 2026).
This page summarizes what clinical trials, meta-analyses and US federal sources report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Type | Herbal dietary supplement made from fenugreek seed (whole seed, powder or standardized extract) |
| Common extract brands in trials | Testofen, Furosap, Trigozim, Fenu-FG and others, each standardized differently |
| Route | Oral |
| Doses in male hormone trials | Mostly 500–600 mg/day of extract for 8–12 weeks; one trial tested up to 1,800 mg/day |
| Half-life | Not established in humans; no human pharmacokinetic studies were found |
| Notable constituents | 4-hydroxyisoleucine, diosgenin, protodioscin, trigonelline, sotolon, mucilage (fiber) |
| Testosterone effect (meta-analysis) | Total testosterone SMD 0.25 (95% CI 0.02–0.48); free testosterone SMD 0.08 (95% CI −0.48 to 0.63); very low certainty |
| US status | Dietary supplement, not FDA-approved for any condition; fenugreek is listed as GRAS (generally recognized as safe) as a spice and natural flavoring |
| WADA status | Not named on the 2026 Prohibited List |
What it is
Fenugreek is native to the Mediterranean region, southern Europe and western Asia. It has been used as a medicinal plant for about 6,000 years, including as a tonic, a laxative, a remedy for menstrual cramps and menopause symptoms, and to stimulate milk production (NCCIH).
The seeds contain a mix of active compounds rather than one main ingredient (LactMed):
| Constituent | What it is | Why it comes up |
|---|---|---|
| 4-Hydroxyisoleucine | An unusual amino acid | Boosts glucose-triggered insulin release in lab studies; linked to fenugreek’s blood-sugar effects |
| Diosgenin, protodioscin and other saponins | Plant steroid sapogenins and their glycosides | The basis of most “testosterone” extracts |
| Trigonelline | A plant compound | One of the markers used to standardize some extracts |
| Sotolon | An aroma compound | Gives fenugreek, and the urine and sweat of people who take it, a maple-syrup smell |
| Mucilage | Seed fiber | Galactomannan fiber extracts were among the preparations tested in diabetes trials |
Commercial products differ a lot. The trials used proprietary extracts standardized to different marker compounds, made with different extraction methods, and sometimes combined with minerals or other herbs. The 2026 meta-analysis concluded that “fenugreek” should not be treated as one uniform intervention for this reason (Yang et al., Front Nutr 2026).
How it works in the body
There are no published human pharmacokinetic studies (absorption, peak level, half-life) for fenugreek or its main constituents that we could verify. Any half-life quoted for “fenugreek” should be treated as unsupported.
What is known about mechanism comes mostly from lab work:
- Insulin release. 4-Hydroxyisoleucine, purified from fenugreek seeds, increased glucose-induced insulin release from isolated rat and human pancreatic islets at 100 µmol/L to 1 mmol/L. The effect only appeared at above-normal glucose levels, not at basal glucose (Sauvaire et al., Diabetes 1998).
- Testosterone. One early fenugreek extract was tested as a “purported” aromatase and 5α-reductase inhibitor (a blocker of the enzymes that turn testosterone into estradiol and DHT). In that 8-week trial in 30 resistance-trained men, there was no significant difference between groups in DHT, which argues against meaningful 5α-reductase blockade at that dose (Wilborn et al., Int J Sport Nutr Exerc Metab 2010). The product was a fenugreek extract standardized for a proprietary marker called Grecunin (Yang et al., Front Nutr 2026).
- Odor. Sotolon is the same compound that gives the urine of maple syrup urine disease (an inherited metabolic disorder) its smell (Korman et al., J Paediatr Child Health 2001).
About “plant steroids” and testosterone. Diosgenin is often described in marketing as a natural testosterone precursor. The human trials measured blood testosterone only; none showed that diosgenin or fenugreek is converted into testosterone in the body. A small change in a blood level is also not the same as improved fertility or muscle growth (Yang et al., Front Nutr 2026).
Regulatory status
- Not an approved drug. In the US, fenugreek is sold as a dietary supplement. Supplements are not approved by the FDA before sale, and manufacturers are responsible for their safety and labeling (NCCIH).
- GRAS as a food ingredient. Fenugreek (Trigonella foenum-graecum L.) appears in the federal lists of spices and natural seasonings and of natural extractives that are generally recognized as safe (21 CFR 182.10; 21 CFR 182.20). This covers its use as a flavoring, not concentrated medicinal doses.
- Sport. Fenugreek is not named on the WADA 2026 Prohibited List (WADA 2026 Prohibited List).
What the research shows
Testosterone in men
The most recent and most cautious review is a 2026 systematic review and meta-analysis of randomized placebo-controlled trials in adult men (Yang et al., Front Nutr 2026). It included 13 trials; 8 reported usable hormone data, and most tested 500–600 mg/day of extract for 8–12 weeks.
| Outcome | Studies (participants) | Pooled effect | Certainty |
|---|---|---|---|
| Total testosterone | 6 (385) | SMD 0.25 (95% CI 0.02–0.48); I² = 0% | Very low |
| Free testosterone | 5 (334) | SMD 0.08 (95% CI −0.48 to 0.63); I² = 66.7% | Very low |
| Total testosterone, BPH trial excluded | 5 | SMD 0.34 (95% CI 0.17–0.52) | Sensitivity analysis only |
SMD (standardized mean difference) expresses the effect in standard-deviation units, and the authors described this one as small. Because the trials used different assays and units, the authors did not translate the result into ng/dL. Key caveats from the review:
- None of the 13 trials was judged at low risk of bias; 11 had “some concerns” and 2 were high risk.
- Industry funding or company involvement was common, and publication bias was suspected.
- Populations were mostly healthy or exercise-trained men, not men with diagnosed low testosterone.
- The authors concluded that current evidence “does not support” clinical or commercial testosterone-boosting claims.
An earlier meta-analysis of 7 studies (449 participants, 378 men and 71 women) reported a similar small effect on total testosterone in male athletes (SMD 0.32; 95% CI 0.09–0.55). Effects on free testosterone, lean body mass, fat mass and leg press all had confidence intervals that crossed zero (Isenmann et al., Int J Sports Med 2023).
Individual trials in men
| Trial | Design and n | Product and dose | Main hormone findings |
|---|---|---|---|
| Wilborn et al. 2010 | Double-blind RCT, 30 resistance-trained men, 8 weeks | Fenugreek extract 500 mg/day | Total testosterone +0.97 ng/mL on extract vs −2.10 ng/mL on placebo (p = 0.018); no group difference in DHT |
| Wankhede et al. 2016 | Double-blind pilot RCT, 60 men in resistance training, 8 weeks | Fenu-FG glycoside fraction, 300 mg twice daily | Authors reported significant “anabolic and androgenic” effects and lower body fat vs placebo; industry-affiliated |
| Rao et al. 2016 | Double-blind RCT, 120 healthy men aged 43–70, 12 weeks | Testofen 600 mg/day | Total and free testosterone rose vs placebo; lower Aging Male Symptom scores |
| Rao and Grant 2020 | Double-blind RCT, 100 men aged 45–80 with BPH, 12 weeks | Testofen 600 mg/day | No change in testosterone, free testosterone, SHBG or PSA; no effect on BPH symptoms |
| Lee-Ødegård et al. 2024 | Double-blind RCT, 95 men aged 40–80 completed, 12 weeks | Trigozim 600, 1,200 or 1,800 mg/day | Plasma total testosterone +9.0% vs placebo (p = 0.122, not significant); saliva testosterone +37.2% vs placebo (p = 0.042) |
The Lee-Ødegård trial is the only one that tested several doses. Plasma testosterone rose from baseline in the extract groups combined, but the difference from placebo was not statistically significant; only saliva testosterone differed from placebo. The authors reported financial ties to the laboratory and funder (Lee-Ødegård et al., PLoS One 2024).
Libido and sexual function
In a 6-week double-blind trial, 60 healthy men aged 25–52 took 600 mg/day of a fenugreek extract combined with minerals, or placebo. The extract group reported higher scores for sexual arousal and orgasm, while serum testosterone and prolactin stayed within the reference range (Steels et al., Phytother Res 2011). Pooled across trials, sexual-function and male-symptom questionnaires leaned in favor of fenugreek, but the 2026 review cautioned that these questionnaire changes cannot be attributed to a testosterone effect (Yang et al., Front Nutr 2026).
Strength and body composition
The 2026 review’s supplementary pooled analyses found body fat −1.37 percentage points (95% CI −2.13 to −0.61) and bench-press 1RM +4.86 kg (95% CI 1.71–8.02) in favor of fenugreek. Fat-free mass and leg-press 1RM showed no stable effect (Yang et al., Front Nutr 2026). Several of these trials paired the supplement with an exercise-training program, and most were small and industry-funded.
Blood sugar
This is the most studied use of fenugreek. A 2014 meta-analysis of 10 trials of fenugreek seed compared with control found (Neelakantan et al., Nutr J 2014):
| Outcome | Change vs control (95% CI) | Trials |
|---|---|---|
| Fasting glucose | −0.96 mmol/L (−1.52 to −0.40), ≈ −17 mg/dL | 10 |
| 2-hour post-load glucose | −2.19 mmol/L (−3.19 to −1.19), ≈ −39 mg/dL | 7 |
| HbA1c | −0.85 percentage points (−1.49 to −0.22) | 3 |
Significant effects were seen only with medium or high doses in people with diabetes, and most trials were of low methodological quality. A 2023 meta-analysis of 10 randomized trials (706 participants with type 2 diabetes or prediabetes) also found lower fasting glucose, post-load glucose and HbA1c (−0.54 percentage points; 95% CI −0.80 to −0.29), with no change in insulin resistance (HOMA-IR) or BMI (Kim et al., Int J Mol Sci 2023). NCCIH notes that many of these studies were not of high quality and that the evidence is not enough to say whether fenugreek is useful for diabetes (NCCIH).
Breast milk supply
Doses used as a galactagogue (a substance taken to increase milk supply) are typically 1–6 g/day (LactMed). A Cochrane review of 41 trials of oral galactagogues rated the evidence for natural products, including fenugreek, as very low certainty and could not pool milk-volume results because the studies were too different (Foong et al., Cochrane 2020). LactMed notes that the effect may be largely psychological.
Side effects and risks
Short trials of 8–12 weeks reported few adverse events and no serious events attributed to fenugreek, but reporting was inconsistent and long-term safety is unknown (Yang et al., Front Nutr 2026). A 2026 scoping review of 60 articles (clinical trials and case reports) found that mild digestive upset was the most common side effect and that no deaths have been attributed to fenugreek (Amiri Ardekani et al., Iran J Med Sci 2026).
Common effects
- Digestive symptoms. Diarrhea, flatulence, nausea and vomiting (LactMed).
- Maple-syrup odor. Urine, sweat and feces can smell of maple syrup. When mothers took fenugreek during labor, the odor in their newborns led to a false suspicion of maple syrup urine disease (Korman et al., J Paediatr Child Health 2001).
- Low blood sugar. Large doses may cause a harmful drop in blood sugar (NCCIH).
Allergy
Fenugreek can cause allergic reactions, including serious ones (NCCIH). Cross-reactivity with chickpeas, peanuts and other legumes is possible, and worsening of asthma has been reported (LactMed; Ouzir et al., Food Chem Toxicol 2016).
Liver, potassium and skin
LactMed summarizes case reports of liver toxicity with fenugreek alone and in herbal mixtures, a 14% fall in serum potassium, and one case of toxic epidermal necrolysis (a severe skin reaction) in a nursing mother (LactMed). These are isolated reports, not trial rates.
Interactions
- Warfarin. A woman on warfarin had a rise in INR (a measure of clotting time) while taking boldo and fenugreek. It returned to normal a week after stopping and rose again when both were restarted (Lambert and Cormier, Pharmacotherapy 2001).
- Diabetes. Because fenugreek can lower blood glucose, LactMed advises caution with high doses in women with diabetes and in those taking warfarin (LactMed).
Pregnancy and fertility
- Pregnancy. NCCIH states fenugreek is not safe during pregnancy in amounts greater than those in food, because its use has been linked to birth defects in animals and people (NCCIH).
- Male fertility (animal data). In rats, mice and rabbits, fenugreek has been associated with testicular toxicity and anti-fertility effects. These findings have not been shown in humans, but human trials have not measured semen quality or fertility either (Ouzir et al., Food Chem Toxicol 2016; Yang et al., Front Nutr 2026).
Quality and product differences
Supplement products may differ from their labels in which ingredients they contain and in what amounts, and a result from one tested product may not apply to another (LactMed). For fenugreek this matters more than usual: the hormone trials tested specific branded extracts standardized to saponins, protodioscin or glycosides, and plain seed powder or other extracts may not behave the same way (Yang et al., Front Nutr 2026).
For other herbs marketed for male hormones, see Tongkat Ali, Tribulus Terrestris and Ashwagandha.
Key takeaways
- A spice, not a hormone. Fenugreek is a GRAS food ingredient sold as a supplement; it is not an approved drug for any condition.
- Testosterone effect is small and uncertain. The 2026 meta-analysis found a small rise in total testosterone (SMD 0.25), no reliable change in free testosterone, and very low certainty of evidence.
- Product matters. Trials used different branded extracts, mostly 500–600 mg/day for 8–12 weeks, often funded by the makers.
- Best evidence is for blood sugar. Meta-analyses show lower fasting glucose and HbA1c in people with diabetes, though most trials were low quality.
- Generally well tolerated in short trials. Digestive upset and a maple-syrup body odor are common; allergy, low blood sugar and a warfarin interaction are documented.
- Avoid in pregnancy beyond food amounts. NCCIH links it to birth defects, and animal studies raise male fertility questions that human trials have not addressed.
Sources
- National Center for Complementary and Integrative Health. Fenugreek. NCCIH.
- Drugs and Lactation Database (LactMed). Fenugreek. National Institute of Child Health and Human Development; updated July 15, 2026. NCBI Bookshelf.
- Code of Federal Regulations. 21 CFR 182.10, Spices and other natural seasonings and flavorings; 21 CFR 182.20, Essential oils, oleoresins (solvent-free), and natural extractives (including distillates). eCFR 182.10; eCFR 182.20.
- World Anti-Doping Agency. The 2026 Prohibited List. In effect January 1, 2026. WADA 2026 Prohibited List.
- Yang P, Niu Z, Guo J, et al. Effects of oral fenugreek-derived preparations on testosterone-related outcomes in adult men: a systematic review and meta-analysis of randomized placebo-controlled trials. Front Nutr. 2026;13:1903508. PubMed.
- Isenmann E, Alisauskas P, Flenker U, et al. The anabolic effect of fenugreek: a systematic review with meta-analysis. Int J Sports Med. 2023;44(10):692–703. PubMed.
- Wilborn C, Taylor L, Poole C, et al. Effects of a purported aromatase and 5α-reductase inhibitor on hormone profiles in college-age men. Int J Sport Nutr Exerc Metab. 2010;20(6):457–465. PubMed.
- Wankhede S, Mohan V, Thakurdesai P. Beneficial effects of fenugreek glycoside supplementation in male subjects during resistance training: a randomized controlled pilot study. J Sport Health Sci. 2016;5(2):176–182. PubMed.
- Rao A, Steels E, Inder WJ, et al. Testofen, a specialised Trigonella foenum-graecum seed extract reduces age-related symptoms of androgen decrease, increases testosterone levels and improves sexual function in healthy aging males in a double-blind randomised clinical study. Aging Male. 2016;19(2):134–142. PubMed.
- Rao A, Grant R. The effect of Trigonella foenum-graecum extract on prostate-specific antigen, and prostate function in otherwise healthy men with benign prostate hyperplasia. Phytother Res. 2020;34(3):634–639. PubMed.
- Lee-Ødegård S, Gundersen TE, Drevon CA. Effect of a plant extract of fenugreek (Trigonella foenum-graecum) on testosterone in blood plasma and saliva in a double blind randomized controlled intervention study. PLoS One. 2024;19(9):e0310170. PubMed.
- Steels E, Rao A, Vitetta L. Physiological aspects of male libido enhanced by standardized Trigonella foenum-graecum extract and mineral formulation. Phytother Res. 2011;25(9):1294–1300. PubMed.
- Sauvaire Y, Petit P, Broca C, et al. 4-Hydroxyisoleucine: a novel amino acid potentiator of insulin secretion. Diabetes. 1998;47(2):206–210. PubMed.
- Neelakantan N, Narayanan M, de Souza RJ, van Dam RM. Effect of fenugreek (Trigonella foenum-graecum L.) intake on glycemia: a meta-analysis of clinical trials. Nutr J. 2014;13:7. PubMed.
- Kim J, Noh W, Kim A, et al. The effect of fenugreek in type 2 diabetes and prediabetes: a systematic review and meta-analysis of randomized controlled trials. Int J Mol Sci. 2023;24(18):13999. PubMed.
- Foong SC, Tan ML, Foong WC, et al. Oral galactagogues (natural therapies or drugs) for increasing breast milk production in mothers of non-hospitalised term infants. Cochrane Database Syst Rev. 2020;5(5):CD011505. PubMed.
- Amiri Ardekani E, Parvizi MM, Zare R, et al. Exploring the adverse effects of fenugreek in humans: a scoping review. Iran J Med Sci. 2026;51(1):4–18. PubMed.
- Ouzir M, El Bairi K, Amzazi S. Toxicological properties of fenugreek (Trigonella foenum graecum). Food Chem Toxicol. 2016;96:145–154. PubMed.
- Lambert JP, Cormier J. Potential interaction between warfarin and boldo-fenugreek. Pharmacotherapy. 2001;21(4):509–512. PubMed.
- Korman SH, Cohen E, Preminger A. Pseudo-maple syrup urine disease due to maternal prenatal ingestion of fenugreek. J Paediatr Child Health. 2001;37(4):403–404. PubMed.