Boron

Trace element with no established human biological role, supplement

ATC code: A12CX-BORON

Brand names: Solgar Boron Citrate, NOW Boron, Pure Encapsulations Boron Glycinate

Updated 30 May 2026 · Methodology

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Low testosterone in men (supplement marketing)

Not recommended

Boron is widely marketed as a «natural testosterone booster». The pitch traces to a small Naghii 2011 study (8 men, one week of 10 mg/day boron) with a 28 % rise in free testosterone. Larger RCTs have failed to reproduce the effect: the Pizzorno 2015 review and NIH ODS 2022 fact sheet note that data in men with normal testosterone are insufficient and inconsistent. Endocrine Society 2018 and ISSAM 2022 do not include boron in hypogonadism guidelines. In men with confirmed symptomatic hypogonadism (testosterone below 12 nmol/L on two morning samples plus symptoms) testosterone replacement is discussed with urology. If boron was bought to raise testosterone, consider seeking a second opinion and start with measuring the level.

Sources

ICD-10: E29.1 · ICD-11: 5A81.1

Osteoporosis

Not recommended

Boron in «bone» supplements is sold on the basis of 1980s epidemiology linking boron intake to reduced urinary calcium and magnesium excretion. Clinical RCTs showing that boron reduces fracture risk or raises bone mineral density in osteoporosis do not exist. NIH ODS notes «insufficient evidence»; has not approved any bone-related health claim for boron. Proven options in osteoporosis: dietary calcium plus vitamin D if deficient, resistance exercise, bisphosphonates, denosumab and anabolic therapy in severe cases. If boron was bought or prescribed as osteoporosis treatment, consider seeking a second opinion.

Sources

ICD-10: M81 · ICD-11: FB83.1

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Boron is essential for plant cell-wall structure; in humans no biological role is proven. Epidemiological work links boron intake to calcium, magnesium and oestradiol metabolism, but RCTs are small and inconsistent. A possible mechanism is influence on steroid-hormone hydroxylases and on 25-hydroxylase of vitamin D. set the Tolerable Upper Intake Level at 10 mg/day for adults in 2004; no adequate intake is defined because essentiality is not confirmed.

Safety

Contraindications

Pregnancy and pregnancy planning
Hormone-sensitive tumours of breast, endometrium and prostate
Severe renal impairment
Known hypersensitivity to borates

Serious adverse effects

Acute boron (boric acid) poisoning – nausea, vomiting, diarrhoea, erythroderma, oliguria, seizures; lethal adult dose 15–20 g
Chronic toxicity at doses above 100 mg/day – dermatitis, alopecia, anaemia

Common adverse effects

Nausea at doses above 10 mg/day
Headache
Irritability

Pregnancy: can you take Boron?

Boron crosses the placenta. Animal data at high doses (above 25 mg/kg/day) show teratogenic effects – skeletal and reproductive malformations. Direct human data are lacking. EFSA 2004 advises not to exceed 10 mg/day in adults. AESAN classifies boron supplements as complementos alimenticios without therapeutic indication. Boron supplements in pregnancy are not justified.

Breastfeeding: can you take Boron?

Boron passes into breast milk. Safety data for supraphysiological doses in the infant are lacking. Boron supplements during lactation are not justified.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

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Frequently asked

What is Boron used for?

Boron is evaluated for the following indications with varying evidence strength: Low testosterone in men (supplement marketing) (evidence tier D), Osteoporosis (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Boron?

Common side effects of Boron (≥ 1 in 100): Nausea at doses above 10 mg/day, Headache, Irritability. See the Safety section for uncommon and serious reactions.

Is Boron safe during pregnancy?

Is Boron compatible with breastfeeding?

Boron passes into breast milk. Safety data for supraphysiological doses in the infant are lacking. Boron supplements during lactation are not justified.

Who should not take Boron?

Boron is contraindicated in: Pregnancy and pregnancy planning; Hormone-sensitive tumours of breast, endometrium and prostate; Severe renal impairment; Known hypersensitivity to borates. Full list in the Safety section.

Official sources

Direct links to regulator labels. Open in a new tab.

FDA / DailyMedLabel dated 05/03/2022

Other drugs in this group

Calcium (oral salts: carbonate, citrate, lactate, gluconate), Calcium carbonate, Calcium + Cholecalciferol, Calcium D-glucarate, Copper, Magnesium sulfate, Phosphorus, Chromium picolinate