Boron is a cheap trace mineral with a large marketing claim and a small evidence base. Its strongest human findings have nothing to do with hormones: less knee pain and stiffness, lower blood markers of inflammation, easier period pain. The testosterone claim is weaker than the confidence with which it is sold. Safety at supplement doses looks reassuring. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Total testosterone | 600–900 ng/dL in men | The headline claim; anchors everything else |
| Free testosterone | 15–25 ng/dL in men | The fraction the SHBG mechanism would actually change |
| Sex hormone-binding globulin (SHBG) | 20–40 nmol/L | The proposed target of boron's action |
| Estradiol (sensitive assay) | 20–30 pg/mL in men | Catches the unpredictable direction of change |
| Dihydrotestosterone | 30–85 ng/dL in men | Reported to rise on boron, and drives scalp and prostate effects |
| 25-hydroxyvitamin D | 40–60 ng/mL | The mechanism predicts a rise here before any hormone change |
| High-sensitivity C-reactive protein | Below 1.0 mg/L | The best-supported human effect of boron |
| Serum calcium | 9.0–9.8 mg/dL | Guards the additive effect with vitamin D and calcium |
| Red blood cell magnesium | 5.0–6.5 mg/dL | Boron's mineral-sparing effect works through magnesium |
| Creatinine with estimated glomerular filtration rate | eGFR above 90 mL/min/1.73 m² | The sole elimination route for boron |
| Prostate-specific antigen | Below 1.5 ng/mL under age 60 | Baseline reference where androgens are being manipulated |
| Blood boron | No established target; change from the individual's own baseline is tracked instead | Confirms exposure where total intake is uncertain |
Cadence: Baseline panel before starting, drawn fasting between seven and nine in the morning. Androgen and estradiol markers repeated at eight weeks, then at six months, then every twelve months while supplementation continues. Serum calcium and renal function at three months in anyone also taking high-dose vitamin D.