Boron
Boron citrate
TL;DR
Boron is a trace mineral affecting bone mineral handling, hormone metabolism and inflammation. Typical supplemental doses are 3–10 mg/day; food supplies 1–3 mg.
Ideal For
- Postmenopausal women concerned about bone mineral loss
- Men interested in hormone metabolism support
- People with osteoarthritis seeking a low-risk adjunct
- Those with low dietary intake of fruit, nuts and legumes
Avoid If
- You are pregnant or trying to conceive
- You have kidney disease — boron is renally cleared
- You are taking doses near or above 20 mg/day
Frequently Asked Questions
Overview
Boron is not formally classified as an essential nutrient for humans, but the evidence that it does something useful is stronger than that status suggests. It is found in fruit, nuts, legumes and wine, with typical intake of 1-3 mg/day, and it influences the metabolism of calcium, magnesium and vitamin D as well as steroid hormones.
The bone research is the oldest thread. In magnesium-deficient postmenopausal women, 3 mg/day reduced urinary calcium and magnesium excretion and raised serum oestradiol and testosterone. Later work is less dramatic but consistent with a role in reducing mineral loss rather than adding bone directly. The hormonal findings have attracted attention: a small study found that 10 mg/day for a week raised free testosterone by around 25% and lowered oestradiol and inflammatory markers in healthy men. The sample was tiny and replication is limited, so treat that as suggestive.
Boron also inhibits several serine proteases, which underpins observational associations between higher regional boron intake and lower arthritis prevalence, and small trials in osteoarthritis reporting symptomatic improvement. The overall picture is a genuinely interesting trace mineral with a thin but non-trivial evidence base.
How It Works
- Reduces urinary excretion of calcium and magnesium, particularly when intake is low
- Extends the half-life of steroid hormones including testosterone and oestradiol
- Inhibits serine proteases involved in inflammatory joint processes
- Supports vitamin D metabolism, raising 25-hydroxyvitamin D in deficient states
- Influences the activity of enzymes requiring nicotinamide adenine dinucleotide
Quick Facts
- Supports bone health
- May benefit hormone levels
- Enhances mineral absorption
- Cognitive benefits
Benefits & Outcomes
Sex Hormone Binding Globulin
One small study is the entire basis for boron's SHBG reputation.
Testosterone Support
Boron may nudge free testosterone by lowering SHBG in very small studies.
Bone Health Support
Boron alters mineral and hormone handling in small studies, but no fracture or density outcomes support it.
Hormonal Balance
Boron measurably shifts testosterone, estradiol and vitamin D markers in small studies, but clinical relevance is unclear.
Joint Comfort
Ecological data linking boron intake to lower arthritis rates has never been confirmed by proper trials.
Cognitive Function
A handful of small studies link low boron intake to poorer attention, but the evidence base is thin.
Health Concerns Addressed
No linked health concerns yet.
Supporting Research6 studies
Dietary boron, brain function, and cognitive performance
Penland JG
When dietary boron was raised from about 0.25 mg to 3.25 mg per day, participants showed improved performance on tasks of attention, short-term memory, manual dexterity and psychomotor speed, alongside EEG changes indicating reduced low-frequency activity and increased alertness.
Boron and bone health: a systematic review
Hunt, C.D.
This review of human and animal data found boron influences calcium, magnesium and vitamin D metabolism and steroid hormone levels, with depletion-repletion studies suggesting boron may reduce urinary calcium loss, but no clinical trials demonstrating reduced fracture risk or improved bone mineral density in humans.
Update on human health effects of boron
Nielsen FH
Evidence supports roles for boron in bone growth, wound healing and inflammatory regulation, but human supplementation trials remain small and inconclusive.
Nothing boring about boron: effects of supplementation on steroid hormones and inflammation
Pizzorno L
Boron supplementation of 6-10 mg/day lowered sex hormone binding globulin and raised free testosterone within one week
Pivotal role of boron supplementation on bone health: A narrative review
Rondanelli M, Faliva MA, Peroni G +1 more
Available human studies suggest boron influences calcium, magnesium and vitamin D metabolism relevant to bone, but no dosing recommendation can be established from current data.
Growing Evidence for Human Health Benefits of Boron
Nielsen FH, Meacham SL
Boron intakes above about 1 mg/day are associated with improved calcium and magnesium metabolism, bone strength and reduced inflammatory markers in experimental and observational work.
Safety Information
Potential Side Effects
Well tolerated at 3-10 mg/day. Very high intakes cause nausea, vomiting, diarrhoea, headache and dermatitis. The margin between supplemental and toxic doses is narrower than for most minerals, so the 20 mg/day upper limit matters.
Contraindications
Avoid in pregnancy: high boron intake is associated with reproductive toxicity in animal studies. Avoid high doses in kidney impairment because clearance is renal.
Drug Interactions
- Magnesium and calcium — boron alters their retention, which is the point rather than a problem
- Oestrogen therapy — boron may raise circulating oestradiol
- No established pharmaceutical interactions at typical doses
Pregnancy & Breastfeeding
Pregnancy: likely_unsafe
Breastfeeding: insufficient_data
Dosage Guidelines
Dosage Used in Studies
3-10 mg
Best Time to Take
With breakfast
Best Form
Boron glycinate or calcium fructoborate, both used in human studies at sensible doses
Bioavailability
Well absorbed trace mineral. Supports bone health and hormone metabolism. May enhance vitamin D and magnesium utilization. Do not exceed 20mg/day long-term.
Forms Compared
Boron glycinate
Boron citrate
Sodium borate (borax)
Calcium fructoborate
Food & Timing
With food; boron is well absorbed either way
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.