Does boron increase testosterone?

A small body of research suggests that 6-10mg of boron daily may modestly raise free testosterone in men by lowering SHBG (the protein that binds testosterone in the bloodstream). The most cited study (Naghii et al., 2011) showed a ~28% increase in free T after one week of 10mg/day. Sample sizes are small and the literature is thin.

How much boron should I take?

The studies showing testosterone effects use 6-10mg per day. The Tolerable Upper Intake Level set by the Institute of Medicine is 20mg/day for adults. Most multivitamins contain 1-3mg. Standalone boron supplements typically come in 3-10mg capsules.

What foods contain boron?

Boron-rich foods include avocados, raisins, prunes, almonds, walnuts, hazelnuts, chickpeas, beans, and apples. A diet heavy in fruits, nuts, and legumes typically provides 2-5mg per day. Supplemental boron at the doses studied for testosterone (6-10mg) is harder to hit through food alone.

Boron at typical supplemental doses (3-10mg/day) appears safe for healthy adults. Doses above 20mg/day can cause nausea, diarrhea, and other GI symptoms. People with kidney disease should avoid supplemental boron without medical guidance, as it's cleared renally.

Supplement Published May 9, 2026

Boron and Testosterone: A Lesser-Known Trace Mineral

Boron doesn't get the attention zinc and magnesium do, but it has shown up in a small handful of testosterone studies with surprisingly consistent results. The literature is thin, the doses are well-defined, and the mechanism is interesting. Here's what's actually known and where the evidence runs out.

What Is Boron?

Boron is a trace mineral found in plant foods, especially fruits, nuts, and legumes. It's not classified as essential by the National Academies (the FDA hasn't set an RDA), but it plays a role in bone metabolism, calcium and magnesium handling, and possibly some hormone activity.

The typical Western diet provides 1 to 3mg of boron per day. People eating a lot of fruit, nuts, and beans can hit 4 to 6mg. The doses studied for testosterone effects (6 to 10mg) sit at or above the high end of normal dietary intake.

The Naghii 2011 Study

The most-cited boron-testosterone study is Naghii et al. (2011), published in the Journal of Trace Elements in Medicine and Biology. Eight healthy men took 10mg of boron daily for one week. Researchers measured serum testosterone, free testosterone, SHBG, and estradiol before and after.

Results after one week:

Total testosterone: modest, non-significant increase
Free testosterone: ~28% increase
SHBG: ~9% decrease
Estradiol: ~39% decrease
Inflammatory markers (hs-CRP, TNF-α): meaningful decreases

The mechanism: by lowering SHBG (sex hormone-binding globulin), more of the existing testosterone becomes free and bioavailable. SHBG normally binds about 60% of circulating testosterone, taking it out of active circulation. Free testosterone is the fraction that can actually enter cells and act on tissues. We cover this distinction in detail in our piece on free testosterone vs total testosterone.

Other Supporting Studies

A handful of additional studies have looked at boron in different populations:

Nielsen et al. (1987) — Postmenopausal women supplementing 3mg/day for 48 days saw increased serum estradiol and testosterone. This was originally a calcium and bone study but the hormone signal was notable.
Pizzorno (2015) — Review article summarized boron's role in steroid hormone metabolism, anti-inflammatory effects, and potential links to vitamin D activation.
Several rat and in-vitro studies — Show effects on Leydig cell function and androgen synthesis at supraphysiological doses.

The human evidence base is small (combined sample sizes in the tens, not thousands), and the longest study is under two months. By the standards of nutritional epidemiology, this is preliminary evidence, not settled science.

Mechanisms: Why Might Boron Work?

SHBG Reduction

The clearest signal is the SHBG decrease. Boron appears to influence the gene expression or clearance of SHBG, freeing up more testosterone. This matters more for older men, who tend to have rising SHBG with age — a major reason free testosterone often falls faster than total testosterone after 40.

Anti-Inflammatory Effects

Boron has documented anti-inflammatory effects, lowering hs-CRP and inflammatory cytokines. Chronic inflammation suppresses testosterone production via cytokine-induced disruption of the HPG (hypothalamic-pituitary-gonadal) axis, so reducing inflammation could indirectly support T.

Vitamin D Interaction

Some research suggests boron may extend the half-life of active vitamin D. Since vitamin D is itself linked to testosterone (covered in vitamin D and testosterone), this could be an indirect pathway.

Practical Dosing

If you decide to experiment with boron based on this evidence:

Dose: 6 to 10mg per day, taken with food
Form: Boron citrate, glycinate, or aspartate are common. Differences are minor.
Timing: No clear advantage to AM vs PM. Take with a meal to reduce any GI discomfort.
Trial length: Most studies show effects within 1 to 8 weeks. If a 6-8 week trial doesn't move bloodwork, it probably isn't doing much for you.

Cost is low — boron supplements typically run $5 to $15 for a 3-month supply. It's one of the cheaper interventions in the supplement world.

Boron-Rich Foods

Before reaching for capsules, you can nudge intake through diet:

Raisins: ~4mg per 100g
Prunes: ~2.5mg per 100g
Almonds: ~2mg per 100g
Avocado: ~1mg per fruit
Hazelnuts: ~1.5mg per 100g
Chickpeas, beans, lentils: 0.5 to 1mg per cup
Apples: ~0.5mg per fruit

A diet heavy in fruits, nuts, and legumes can comfortably hit 4 to 6mg per day. Hitting 10mg through food alone is harder but not impossible.

Honest Caveats

The boron-testosterone literature has real limitations:

Sample sizes are small (under 30 men in most studies)
Study durations are short (1 to 8 weeks)
No large randomized trials have replicated the Naghii 2011 result
Effects may be largest in men with elevated SHBG and minimal in men with normal SHBG
The free testosterone increase doesn't necessarily translate to clinical outcomes (energy, body composition, etc.)

Treat boron as a low-cost, low-risk experiment with modest evidence behind it — not a hormonal cheat code. If you're going to try it, get baseline bloodwork (total T, free T, SHBG, estradiol), supplement for 8 weeks, and re-test. Your data is more useful than another anecdote.

Quick Takeaways

One small study (Naghii 2011) showed 10mg/day boron raised free testosterone ~28% via SHBG reduction.
Mechanism: lowers SHBG, reduces inflammation, possibly extends vitamin D half-life.
Dose used in studies: 6-10mg per day. Upper safe limit: 20mg per day.
Largest potential benefit in men with elevated SHBG (often older men).
Evidence base is small; treat as a low-cost experiment, not a confirmed intervention.

Not medical advice. Talk to your doctor before adding supplements, especially if you have kidney disease or take prescription medications.