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 here. 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.
The app does not replace medical advice.
Related
Sources
- European Commission: EU Register on nutrition and health claims, accessed November 2026
- BfR: Maximum level proposals for boron in foods including food supplements
- NIH Office of Dietary Supplements: Boron, Fact Sheet for Health Professionals
- 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
- Green NR et al.: Plasma boron and the effects of boron supplementation in males. Environ Health Perspect, 1994
- 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
- Heffernan SM et al.: The Role of Mineral and Trace Element Supplementation in Exercise and Athletic Performance: A Systematic Review. Nutrients, 2019