"Natural testosterone booster" is one of the most crowded supplement categories. The evidence base is much smaller than the shelf.
The review
A 2021 systematic review in Advances in Nutrition collected randomized controlled trials of single herbal ingredients on testosterone in adult men. It found 13 herbs tested in 32 studies, published from 2001 to 2019.
- Only 9 of 32 studies showed a statistically significant increase in testosterone.
- Only 6 of 32 were judged to have a low risk of bias.
- The most consistent positive findings were for fenugreek seed extracts and ashwagandha root or root/leaf extracts.
- There was some evidence for Asian red ginseng and a forskohlii root extract.
So for most herbs on most labels, the controlled-trial evidence for raising testosterone is weak or absent.
Mineral blends
ZMA (zinc, magnesium and vitamin B6) is often marketed for testosterone. In a controlled study in men eating a zinc-sufficient diet, ZMA raised blood and urinary zinc but produced no significant change in serum total or free testosterone, and no change in testosterone metabolites. Topping up a mineral you already have enough of is not the same as fixing a deficiency.
The comparison nobody puts on the label
In a small study at the University of Chicago, 10 healthy young men restricted their sleep to 5 hours a night for one week. Their daytime testosterone fell by 10% to 15%. The authors note that normal aging lowers testosterone by about 1% to 2% a year.
That is one small study, not a trial against supplements. But it puts the size of the herbal effects in context: sleep is a lever measured in double-digit percentages, for free.
If you want to test something anyway
- Get a baseline blood test. Without one you cannot tell whether anything changed.
- Pick one ingredient with RCT support, not a 12-ingredient blend.
- Retest after a defined period and decide.
For the two candidates with the most data, see ashwagandha and testosterone and vitamin D and testosterone.
Sources
- Smith SJ, Lopresti AL, Teo SYM, Fairchild TJ. 2021. Examining the Effects of Herbs on Testosterone Concentrations in Men: A Systematic Review. Adv Nutr 12(3):744-765. PubMed 33150931
- Koehler K et al. 2009. Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement. Eur J Clin Nutr. PubMed 17882141
- Leproult R, Van Cauter E. 2011. Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA 305(21):2173-4. PubMed 21632481
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