Boron

non-nutrient/non-botanicalboron atom

What is it

Boron is a trace element found in soil, water, and many plant foods. It is not classified as essential for humans by all authorities, but it appears to influence bone health, hormone metabolism, brain function, and inflammation. Most adults consume 0.5-3 mg of boron per day from diet.

How it works

Boron's biological actions are not as well characterized as those of established essential minerals. It appears to influence calcium, magnesium, and vitamin D metabolism, supporting bone health. It also affects steroid hormone metabolism (testosterone, estrogen) and may inhibit certain enzymes involved in inflammation and cell signaling. Boron is also a component of borate-based compounds with anti-inflammatory effects. Dietary boron is absorbed efficiently from the gut, with most excreted in urine. Studies have shown that increasing boron intake from 0.5 mg/day to 3 mg/day can produce measurable changes in calcium loss, hormone levels, and inflammation markers in some populations. Higher doses are not clearly more beneficial and may pose toxicity concerns.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Bone health

Grade C

Moderate evidence

Boron supplementation has been associated with reduced urinary calcium loss and modest effects on bone mineral density markers in some studies. Effects on fracture risk are not established.

Testosterone / hormone metabolism

Grade C

Moderate evidence

Small studies have shown that boron supplementation (3-10 mg/day) can modestly increase free testosterone levels and lower sex hormone-binding globulin (SHBG) in men. Effects on women include modest changes in estrogen metabolism.

Osteoarthritis

Grade C

Moderate evidence

Observational data suggest that populations with higher dietary boron have lower rates of osteoarthritis. Small clinical trials have shown some symptom relief with boron supplementation; evidence is limited.

Cognitive function

Grade C

Moderate evidence

Limited studies have shown improvements in cognitive measures (attention, short-term memory) when low-boron diets are supplemented to adequate levels. Effects in already-adequate individuals are unclear.

Inflammation

Grade C

Moderate evidence

Boron has anti-inflammatory effects in laboratory studies, and some clinical research has shown reductions in inflammation markers with supplementation. Clinical significance varies.

4 commercial forms

Boron glycinate (chelate)

Well absorbed; commonly used chelated form

Boron bonded to glycine for improved tolerance and absorption.

Boron citrate

Good absorption

Another commonly used form.

Sodium borate / sodium tetraborate (borax)

Absorbed but can be irritating

Less common in supplements; more typically used in industrial settings.

Boron from food sources

Well absorbed (~90%)

Naturally occurring boron in plants is the primary dietary source.

Dosage

There is no formal Recommended Dietary Allowance (RDA) for boron. Adequate Intake (AI) suggested by some authorities is around 1-3 mg per day. Supplements typically provide 3-10 mg per serving. The Tolerable Upper Intake Level (UL) set by the Institute of Medicine is 20 mg per day for adults.

When and how to take it

Take with food to minimize gastrointestinal upset. Timing is not particularly important; most studies have used once-daily dosing. Effects on hormones and bone metabolism develop over weeks to months of consistent intake.

Food sources

Food	Amount	%DV
Prunes (dried plums)	~1.4 mg per 100 g	—
Raisins	~1.2 mg per 100 g	—
Almonds	~2.8 mg per 100 g	—
Avocados	~2 mg per fruit	—
Apples	~0.3 mg per medium apple	—
Peanuts and peanut butter	~0.5-1 mg per 30 g	—
Hazelnuts	~2.8 mg per 100 g	—
Beans (kidney, navy)	~0.5 mg per cup	—

Safety

Generally safe at typical dietary and supplement levels. High-dose boron toxicity can cause nausea, vomiting, diarrhea, headache, and skin rash. Very high doses (well above the UL) can affect reproductive organs based on animal studies. Workplace boron exposure has been associated with respiratory irritation.

Who should be cautious

Pregnant and breastfeeding women should not exceed the UL (20 mg per day for adults) due to potential reproductive concerns at very high doses. People with hormone-sensitive conditions, kidney disease, or those taking hormonal medications should consult a clinician before high-dose supplementation. Children have lower ULs based on age.

Interactions

Boron may interact with hormonal medications (estrogen, testosterone) by affecting steroid metabolism. Theoretical interactions exist with magnesium and calcium supplementation, with some studies suggesting boron influences mineral retention. No major drug interactions are well established.

Frequently asked questions

Is boron an essential nutrient?⌄

Not formally classified as essential by all authorities, but evidence supports a beneficial role in bone, hormone, and brain function. Adequate intake is 1-3 mg per day.

Does boron really raise testosterone?⌄

Some small studies have shown modest increases in free testosterone with 3-10 mg/day boron supplementation in men. Effects are small and not a substitute for established testosterone-supporting strategies.

How much boron is safe?⌄

The Tolerable Upper Intake Level for adults is 20 mg per day. Most supplements provide 3-10 mg per serving, which is well within safe limits.

Can boron help with arthritis?⌄

Observational data and small trials suggest possible benefit for osteoarthritis symptoms. Evidence is preliminary.

Will I get enough boron from food?⌄

Most adults consume 0.5-3 mg per day from diet. Diets rich in fruits, nuts, and legumes provide adequate boron without supplementation.

References

Boron (Wikidata) — Wikidata link
Boron (ChEBI 27560) — ChEBI link
NIH ODS - Boron — NIH Office of Dietary Supplements link

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Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.