# Boron: no confirmed benefit, clear limits

Not a single health claim for boron is authorised in the EU.[^1] EFSA does not class it as an essential nutrient, and the BfR proposes a small maximum level.[^2]

**This is information, not a recommendation.** We do not advise you to take anything. **Under 18 or with an eating disorder, including a past one:** this text is not aimed at you, and you will find places to turn to under [When to get medical advice](https://kostenlos-abnehmen.de/en/wissen/aerztlicher-rat). During pregnancy or breastfeeding, with kidney disease or on medication, ask a doctor first.

## What is known about boron

Boron occurs naturally in foods and some mineral waters. No specific function in humans has been shown so far, and neither EFSA nor the German-speaking nutrition societies give a recommended intake.[^2] The US NIH does not class boron as essential either.[^3]

No claim on boron is authorised in the EU Register, including on bones, joints or the thyroid.[^1] According to the NIH, whether products affect bones remains open.[^3] If you read something like that on a pack, be sceptical.

## Testosterone and muscle: what studies show

| Study | Who | Amount | Result |
| --- | --- | --- | --- |
| Ferrando 1993, Green 1994 | 19 bodybuilders with a placebo group, probably the same group in two papers | 2.5 mg a day for 7 weeks | No effect on testosterone, lean mass or strength[^4][^5] |
| Naghii 2011 | 8 men, no separate placebo group | 10 mg a day for 1 week | Free testosterone higher. The dose is 20 times the BfR proposal[^6][^2] |

A systematic review of minerals in sport found 4 papers on boron and little evidence overall of better performance.[^7] So “testosterone booster” is not a term the research supports.

## Upper limits

| Value | Amount | Note |
| --- | --- | --- |
| BfR proposed maximum | 0.5 mg per daily portion | With a note that the product is not suitable for children and young people[^2] |
| EFSA upper limit | 10 mg a day | For adults, 9 mg for ages 15 to 17[^2] |
| Worst case from food and water alone | about 9 mg a day | BfR estimate without a product, with a boron-rich diet and boron-rich mineral water[^2] |

The limits go back to animal studies: in pregnant rats fetal weight fell, and feeding studies harmed the male reproductive system.[^2] According to the BfR, products with boron are not suitable for young people.[^2] During pregnancy and breastfeeding, ask a doctor first.

## Sources

[^1]: [European Commission: EU Register on nutrition and health claims, accessed November 2026](https://ec.europa.eu/food/food-feed-portal/screen/health-claims/eu-register)
[^2]: [BfR: Maximum level proposals for boron in foods including food supplements](https://www.bfr.bund.de/cm/343/hoechstmengenvorschlaege-fuer-bor-in-lebensmitteln-inklusive-nahrungsergaenzungsmitteln.pdf)
[^3]: [NIH Office of Dietary Supplements: Boron, Fact Sheet for Health Professionals](https://ods.od.nih.gov/factsheets/Boron-HealthProfessional/)
[^4]: [Ferrando AA et al.: The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders. Int J Sport Nutr, 1993](https://pubmed.ncbi.nlm.nih.gov/8508192/)
[^5]: [Green NR et al.: Plasma boron and the effects of boron supplementation in males. Environ Health Perspect, 1994](https://pubmed.ncbi.nlm.nih.gov/7889885/)
[^6]: [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](https://pubmed.ncbi.nlm.nih.gov/21129941/)
[^7]: [Heffernan SM et al.: The Role of Mineral and Trace Element Supplementation in Exercise and Athletic Performance: A Systematic Review. Nutrients, 2019](https://pubmed.ncbi.nlm.nih.gov/30909645/)

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Last updated: November 2026. This is general information and not medical advice.

Original article: https://kostenlos-abnehmen.de/en/wissen/bor