Testosterone Boosters

What it is

Testosterone boosters are over-the-counter supplements marketed to raise testosterone. Common ingredients are herbs such as ashwagandha, fenugreek, tribulus terrestris and tongkat ali (Eurycoma longifolia), and nutrients such as zinc, magnesium and vitamin D [1] [2]. Products usually mix several ingredients: a survey of 50 top-selling boosters found about eight ingredients per product on average, and doses vary widely between products [2].

How it might work

Herbal boosters such as ashwagandha are proposed to act on the hormone systems that govern the stress response and testosterone production - the hypothalamic-pituitary-adrenal and gonadal axes [3]. Zinc is involved in normal hormone metabolism, and low zinc status is linked with lower testosterone [4] [5]. These are proposed mechanisms; the trials cited below test the supplements themselves.

What the research says

Ashwagandha. A 2026 meta-analysis of 23 randomized trials (1,706 adults) found testosterone about 57 ng/dL higher than placebo in men but not in women, and warned that results were heterogeneous [3]. In a trial of 57 young men doing resistance training, 600 mg a day for 8 weeks raised testosterone by about 96 ng/dL versus 18 ng/dL with placebo [6]. In aging, overweight men, saliva testosterone rose 14.7% more than with placebo [7], and a 12-week trial in stressed, overweight adults found free testosterone rose in the men [8].

Fenugreek. A 2026 systematic review and meta-analysis of six trials found a small favorable effect on total testosterone (standardized mean difference 0.25) but very low certainty, with no stable effect on free testosterone; its authors concluded the evidence does not support the marketed claim that fenugreek raises testosterone [9]. An earlier meta-analysis of seven studies in male athletes found a similar small effect (SMD 0.32) [10]. A 2024 trial found a 37% rise in saliva testosterone versus placebo but no significant rise in blood plasma [11].

Tongkat ali. Across five small randomized trials, tongkat ali raised total testosterone (SMD 1.35, 95% CI 0.57 to 2.14) [12]. In 32 young men, 600 mg a day for two weeks raised testosterone and free testosterone [13], and in a 6-month trial of 45 men with age-related androgen deficiency, a 200 mg supplement plus exercise improved erections and raised total testosterone [14]. A 2024 review still rated it only possibly effective because the trials are small [15].

Tribulus. In a 2025 review of 10 trials (483 men), 8 of 10 found no significant change in the androgen profile; the two positive studies were small and in men with hypogonadism (rises of 60-70 ng/dL) [16]. A 2026 meta-analysis found tribulus improved erectile-function scores versus placebo but made no difference to total testosterone [17].

D-aspartic acid. Two randomized trials - 3 g a day for 28 days, and 6 g a day for 12 weeks - found no change in total or free testosterone [18] [19]. One 2025 trial in infertile men found higher testosterone with a product combining D-aspartic acid, coenzyme Q10 and zinc, so the effect cannot be attributed to D-aspartic acid alone [20].

Zinc. When older men with marginal zinc deficiency took about 30 mg of zinc a day for up to six months, testosterone rose from about 8.3 to 16 nmol/L [5]. A 2023 review of 8 clinical and 30 animal studies concluded zinc mainly helps when zinc status is low [4]. In athletes with adequate intake, an 8-week zinc-magnesium (ZMA) trial found no hormone changes [21].

Magnesium. One 4-week trial found magnesium increased free and total testosterone in athletes and sedentary men [22]. The rest of the evidence points away from an effect: the ZMA trial found no hormonal change [21], and the 2024 booster review listed no magnesium product among the few it counted as effective [15].

Vitamin D. Two meta-analyses of randomized trials found vitamin D supplements did not raise total testosterone in men [23] [24]; a 12-week trial in healthy men with lower vitamin D found no change [25], and three small trials in men with heart failure, nursing-home residents and deficient immigrants found no increase [26].

DHEA. DHEA is a hormone sold as a supplement. A meta-analysis of 42 studies found it raised testosterone by about 28 ng/dL on average (about 21 ng/dL in men) [27]. In 25 trials of older men, however, it did not improve sexual function, quality of life or most metabolic measures [28].

Overall. A 2024 systematic review of 52 studies covering 27 boosters found most did not raise total testosterone; only a few were counted as possibly effective - HMB and betaine for male athletes, tongkat ali, a pomegranate-cocoa blend and a shilajit extract for older men with low testosterone, and tongkat ali and ashwagandha for healthy men [15]. A survey of 50 popular products found that only about a quarter had published data showing a testosterone increase and 61.5% had no published data on their effect at all [2].

Doses used in studies

Trials cited here used: ashwagandha 600 mg a day for 8 weeks [6], 21 mg a day of withanolide glycosides [7] and 400 mg a day for 12 weeks [8]; fenugreek extract 600-1,800 mg a day for 12 weeks [11]; tongkat ali 600 mg a day for 2 weeks [13] and a 200 mg supplement for 6 months [14]; tribulus 400-750 mg a day for 1-3 months [16]; D-aspartic acid 3-6 g a day [18] [19]; zinc about 30 mg a day for 3-6 months [5]; magnesium 10 mg per kilogram of body weight a day for 4 weeks [22]; vitamin D 20,000 IU a week for 12 weeks [25]; and DHEA over 50 mg a day in the dose subgroup with the larger effect [27]. These are study doses, not recommendations.

Safety and interactions

• Common side effects. In the trials cited here, side effects were generally mild and similar to placebo: a meta-analysis of eight tribulus trials found no difference in adverse events versus placebo [17], and a 12-week fenugreek trial reported none [11].
• Liver injury. Case series have linked ashwagandha to liver injury. Five people in Iceland and the US developed jaundice and itching 2 to 12 weeks after starting ashwagandha; liver tests returned to normal within 1 to 5 months [29]. In a series of eight people in India taking single-ingredient ashwagandha products, three with pre-existing liver disease died of acute-on-chronic liver failure [30]. People with liver disease are the group at highest risk [30].
• Doses above safe limits. In a survey of 50 popular boosters, 13 products exceeded the FDA upper limit for at least one ingredient (most often zinc, vitamin B3 or magnesium), and products contained a median of 272% of the recommended daily allowance for zinc [2].
• Hidden prescription drugs. FDA warnings from 2007-2016 most often involved supplements marketed for sexual enhancement, weight loss or muscle building; 89.1% of the muscle-building products contained synthetic steroids or steroid-like ingredients, and 47.0% of the sexual-enhancement products contained sildenafil (the drug in Viagra) [31]. Sports supplements are also known to sometimes contain anabolic steroids, which can cause a failed doping test [32].
• Medicines. The trials cited on this page did not report medicine interactions; ask a doctor or pharmacist before combining these supplements with prescription medicines.
• Pregnancy and breastfeeding. The trials cited here were in men; there are no data on these products in pregnancy or breastfeeding [9] [15].

Caveats and open questions

Most trials are small, short (two weeks to six months) and often linked to supplement makers - the 2024 fenugreek trial was funded by a commercial supplement company [11], and industry ties are common in this literature [8]. Measurements differ between studies: fenugreek raised saliva testosterone but not plasma testosterone [11], and long-term effects are unknown because the longest trial cited here ran about six months [14]. The 2026 fenugreek review rated the certainty of the evidence very low [9], and extracts vary so much between products that results for one may not apply to another [15].