Boron
An under-appreciated trace mineral. Supports bone density, raises free testosterone modestly, lowers SHBG, and reduces inflammatory markers.
Moderate evidence for bone density support (preserves calcium, magnesium, and vitamin D status), modest free testosterone elevation in men (Nielsen et al.), free estrogen support in postmenopausal women, and reduced joint pain in osteoarthritis (calcium fructoborate trials). Effects on hormones: 1–4 weeks. Joints: 6–8 weeks. Bone: 6–12 months.
Boron is a trace mineral that isn't formally classified as essential but has consistent biological effects when supplemented. It influences hormone metabolism — most notably reducing SHBG (sex-hormone-binding globulin) and raising free testosterone in men and free estrogen in women. It also supports bone matrix and joint function, partly through cofactor effects on vitamin D and magnesium metabolism. Doses are tiny (single-digit mg) and effects accumulate over weeks. Easy to overlook because it's rarely in multivitamins.
- Form
- Boron glycinate, boron citrate, or calcium fructoborate. All work; calcium fructoborate is the most-studied form for joint pain specifically.
- Dose
- 3–10 mg/day. 6 mg is the typical effective dose; 10 mg is the high end. Don't exceed 20 mg/day chronically.
- Timing
- AM with food. With magnesium or calcium for bone-support synergy.
- Schedule
- Daily.
- Side effects
- Generally well-tolerated. GI upset, headache, skin rash at high doses (>20 mg).
- Interactions
- Mild estrogen-elevating effect — caution combining with HRT or estrogen-sensitive conditions. May modestly raise SHBG-bound steroid levels.
- Contraindications
- Estrogen-sensitive cancers (caution). Pregnancy (high doses associated with developmental effects in animals — keep below RDA).
- Lab markers
- Boron is not routinely tested. Track functional markers: total + free testosterone (men), SHBG, vitamin D, calcium, DEXA scan for bone density.
- Food sources
- Prunes (one of the richest sources), avocado, raisins, nuts (almonds, hazelnuts), apples, pears, broccoli, chickpeas. Diets rich in fruit and nuts deliver 2–5 mg naturally; supplementation tops up to therapeutic levels.
Pairs with
Magnesium, calcium, vitamin D3, vitamin K2 — the bone-support stack. Joints: collagen and glucosamine.
within Minerals