Evidence Level
Moderate
2 Clinical Trials
4 Documented Benefits
3/5 Evidence Score

Boron is a trace mineral found naturally in fruits, vegetables, and nuts that plays underappreciated roles in bone metabolism, testosterone synthesis, vitamin D activation, and cognitive function. Research shows boron significantly affects hormonal balance and bone density even at small supplemental doses.

Studied Dose 3–10 mg/day elemental boron
Active Compound Boron as calcium fructoborate / sodium borate / boron glycinate

Bone health and density

Boron reduces urinary excretion of calcium and magnesium, and stimulates production of 1,25-dihydroxyvitamin D3 — the active form of vitamin D. Studies show significant improvements in bone density markers.

Testosterone support

A 7-day supplementation study at 10 mg/day showed a 28% increase in free testosterone and 39% decrease in estradiol in men. Boron inhibits SHBG binding, freeing bound testosterone.

Vitamin D activation

Boron enhances the hydroxylation of vitamin D to its active form (1,25-dihydroxyvitamin D3), effectively amplifying vitamin D activity — important in vitamin D-deficient individuals.

Cognitive function

Nutritional boron deprivation studies show impaired cognitive performance, hand-eye coordination, and EEG activity — suggesting boron plays an active role in brain electrical function.

1

Sex hormone binding globulin inhibition

Boron binds to SHBG (sex hormone binding globulin), reducing its capacity to bind testosterone and estradiol. This increases free (bioavailable) hormone concentrations without affecting total hormone production.

2

Vitamin D and steroid hormone metabolism

Boron modulates the hydroxylase enzymes involved in converting vitamin D to its active form and influences steroid hormone catabolism in the liver.

3

NF-κB and inflammatory signaling

Boron supplementation reduces NF-κB activation and downstream inflammatory cytokines (IL-6, TNF-α), contributing to anti-inflammatory effects observed in joint pain studies.

1
Boron Supplementation and Testosterone in Men
PubMed

Clinical study of 10 mg/day boron in 8 healthy men for 7 days — evaluating hormone levels pre/post.

8 healthy men. 7-day supplementation.

Free testosterone increased 28.3%, estradiol decreased 38.9%, SHBG decreased, and DHT increased. Also showed significant reductions in inflammatory markers (IL-6, CRP, TNF-α).

2
Dietary Boron and Bone Metabolism in Postmenopausal Women
PubMed

Depletion-repletion study examining boron deprivation (0.23 mg/day) vs. adequate intake (3.23 mg/day) in postmenopausal women.

12 postmenopausal women on controlled diets. Crossover design.

Boron deprivation significantly increased urinary calcium and magnesium excretion. Adequate boron reduced these losses and increased serum 17β-estradiol and testosterone.

Common Potential side effects

Generally well tolerated at doses below 20 mg/day
Nausea, vomiting, and diarrhea at very high doses (>100 mg/day)
Skin rash in boron-sensitive individuals (rare)

Important Drug interactions

Hormone therapies — boron affects sex hormone metabolism; use cautiously with HRT or testosterone therapy
Anticoagulants — may mildly affect clotting factors; monitor
Magnesium and calcium supplements — boron reduces their urinary loss; may affect supplementation needs