Boron
What it is
Trace mineral proposed to lower sex hormone-binding globulin (SHBG) and estradiol, modestly raising free (bioavailable) testosterone.
What the evidence says
Evidence is preliminary and thin. The most cited study gave 8 healthy men 10 mg boron daily for one week and reported increased free testosterone and decreased estradiol and SHBG. But this was tiny, short, and uncontrolled (no placebo group), measuring acute changes. No large, randomized, placebo-controlled trials confirm a meaningful or durable testosterone benefit in men, so claims should be treated as hypothesis-generating rather than established.
About 6-10 mg/day of elemental boron in the studied protocols; NIH notes no established requirement, with a tolerable upper limit of 20 mg/day for adults.
Educational summary of doses studied — not a recommendation. Talk to a clinician before starting any supplement.
Sources (1)
- Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines — Journal of Trace Elements in Medicine and Biology, 25(1):54-58 (Naghii et al.) (2011)
Educational summary of published research, checked against primary sources and linked inline. Not medical advice; supplements are not FDA-evaluated to treat disease. See our editorial policy.