Boron: Bone, Joint and Hormone Claims Checked
What small studies and reviews found for boron and bone, joints and testosterone, where proper evidence was not found, and the upper limits Health Canada lists by age.
Content last updated . This page has not been medically reviewed.
How the sources describe boron
A 1994 review described boron-deprivation experiments in people as yielding "persuasive findings for the hypothesis that boron is an essential nutrient". [1] That is a hypothesis stated in 1994. We did not find, in the sources we read, a recommended daily intake for boron. Health Canada's reference-values page lists upper limits for it. [2] Amounts in this page are milligrams (mg) of boron.Evidence labels used
Preliminary means very small studies. Biomarker means a blood test, not a fracture, pain score or testosterone-related symptom. Proper evidence not found means we searched and found nothing usable.What the research found
| Claim | What the sources found | Label |
|---|---|---|
| Bone health | A 1994 review: 12 postmenopausal women ate a low-boron diet for 119 days, then added 3 mg boron a day for 48 days. Plasma calcium and urinary calcium and magnesium fell and serum estradiol and testosterone rose. [1] | Preliminary; biomarkers |
| Bone health | A 2020 narrative review of 11 studies (594 people) said boron at 3 mg a day was useful for bone health, but it also said there are "still no precise indications" about its role or amounts. [3] A narrative review does not select or grade studies by fixed rules. | Preliminary |
| Testosterone and hormones | 8 healthy men took 10 mg boron a day for a week. Free testosterone rose and estradiol fell; the comparison was a placebo capsule on one earlier day, not a control group. [4] | Preliminary; biomarkers |
| Arthritis and joint pain | Proper evidence not found. We searched PubMed for boron and osteoarthritis or arthritis trials and found no human trial we could read; the matches were a 1994 review and a horse study. | Insufficient |
Hormone changes in a lab test do not show that someone feels stronger, builds more muscle or has better fertility. The studies above did not measure those outcomes. The popular claims that boron "boosts testosterone" or "eases arthritis" are marketing claims in this sense, and we found no trial in the sources read that tested them as clinical outcomes.
Upper limits
Health Canada lists these upper limits (UL) for boron, the same for males and females. [2]| Group | UL (mg boron a day) | Source and year |
|---|---|---|
| Children 1-3 years | 3 | Health Canada 2025 [2] |
| Children 4-8 years | 6 | Health Canada 2025 [2] |
| 9-13 years | 11 | Health Canada 2025 [2] |
| 14-18 years, including pregnancy and breastfeeding | 17 | Health Canada 2025 [2] |
| Adults 19 and over, including pregnancy and breastfeeding | 20 | Health Canada 2025 [2] |
| Infants under 12 months | Not determined | Health Canada 2025 [2] |
We could not read an NIH ODS or EFSA page for boron, so we are not quoting limits from those bodies. A limit is not a target, and it is not a promise of safety.
Frequently asked questions
Is boron an essential mineral?
A 1994 review called it a hypothesis supported by "persuasive findings" from deprivation studies. [1] We did not read a recommended intake for boron.
Does boron improve bone density?
We did not find a trial showing fewer fractures. A 2020 narrative review was positive but said there are still no precise indications about amounts, [3] and the 1994 work measured blood and urine markers. [1]
Does boron raise testosterone?
A small study in 8 healthy men reported higher free testosterone after a week at 10 mg a day. [4] It was not a controlled trial of symptoms, so we label it preliminary.
Does boron help arthritis?
Proper evidence not found: we searched PubMed for boron and osteoarthritis trials and found no usable human trial.
How much boron is too much?
Health Canada lists an adult upper limit of 20 mg of boron a day, lower for children and teens. [2] Talk to a clinician or pharmacist before using it.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and who should ask first
- Hormone-sensitive situations. Because studies reported changes in estradiol and testosterone, [1] [4] anyone with a hormone-related condition or on hormone treatment should ask a doctor before using boron.
- Pregnancy, breastfeeding and children. Ask a doctor or midwife. Children's limits are low; see the table.
- Kidney and liver disease, medicines and surgery. The sources we read did not address boron in these situations. Ask a clinician or pharmacist, and see Medication interactions and Supplements before surgery.
- Product quality. The FDA says it is not authorized to approve dietary supplements for safety and effectiveness before they are marketed. [5] See Quality testing and certifications.
For bone health, the best-studied minerals are on Calcium, and general bone care is on Osteoporosis and bone health. Other joint and bone products are on Bone, joint and recovery formulas. Silica claims are on Silica claims checked, and the overall library is at Minerals.
References
- Nielsen FH, Biochemical and physiologic consequences of boron deprivation in humans, Environ Health Perspect 1994 (abstract read). Read 2026-10-23.
- Health Canada, Dietary reference intakes tables: reference values for elements (page dated 2025-11-19; read through a web-fetch tool that summarizes pages). Read 2026-10-23.
- Rondanelli M et al., Pivotal role of boron supplementation on bone health: a narrative review, J Trace Elem Med Biol 2020 (abstract read). Read 2026-10-23.
- Naghii MR et al., Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines, J Trace Elem Med Biol 2011 (abstract read). Read 2026-10-23.
- US FDA, Information for Consumers on Using Dietary Supplements. Read 2026-10-23.