Myths About Boron
Boron rarely makes headlines in mainstream nutrition, yet in fitness forums it has a reputation as a cheap "natural testosterone booster." Claims range from dramatic muscle gains to cures for arthritis. Our editorial team took the most common myths about boron and checked them against the research.
Boron in brief
Boron is a trace element found mainly in plant foods: fruits such as prunes, raisins, and avocados, as well as nuts, legumes, coffee, and wine. In plants, it is clearly essential for cell wall structure. In humans, its essentiality has not been firmly established, which is why there is no Recommended Dietary Allowance.
The US Institute of Medicine (now the National Academies) did, however, set a Tolerable Upper Intake Level of 20 mg per day for adults. Typical American diets provide roughly 1–3 mg per day, with higher intakes among people who eat lots of fruits, vegetables, and nuts.
Research suggests boron interacts with the metabolism of calcium, magnesium, and vitamin D, and may influence steroid hormones. Most of these findings come from small studies, often decades old, which partly explains why the myths have been able to flourish.
Supplements typically provide boron as citrate, glycinate, or aspartate, commonly in 3 mg or 6 mg doses. It also appears in many multivitamin and bone-health formulas at lower amounts.
Myth 1: Boron significantly raises testosterone
This is the claim that drives most boron sales. It largely rests on a small study by Naghii and colleagues in which eight healthy men took 10 mg of boron daily for a week. Free testosterone increased and estradiol decreased, along with drops in some inflammatory markers.
The study was short, uncontrolled, and very small. Increases were in free testosterone, not necessarily total testosterone, and the clinical significance of a one-week change is unclear. It has not been convincingly replicated in larger, placebo-controlled trials.
Other research paints a less exciting picture. A 1993 trial by Ferrando and Green in male bodybuilders found that 2.5 mg per day for seven weeks did not raise testosterone more than placebo; both groups improved due to training itself.
Older research in postmenopausal women by Nielsen and colleagues reported increases in sex hormones after boron repletion following a low-boron diet. However, these were women in a controlled metabolic setting, and the results do not translate to young men looking for an anabolic edge.
Myth 2: Boron builds muscle and strength
Even if boron modestly affected free testosterone in some people, that would not automatically mean more muscle. Changes within the normal physiological range have small effects on body composition compared with training, protein intake, and sleep.
Direct studies on muscle mass and strength are scarce. The Ferrando and Green trial, which specifically measured lean body mass and strength, found no advantage over placebo. No high-quality trial since has shown that boron supplementation improves resistance-training outcomes.
Athletes looking for proven ergogenic aids would do better with substances backed by strong evidence, such as creatine monohydrate or caffeine, rather than relying on boron for physique changes.
Myth 3: More is better, and it is harmless
Because boron is "natural" and sold cheaply, some people take high doses in the belief that more will amplify the effect. This ignores basic toxicology. Boric acid and borates are toxic in excess, and accidental ingestion has caused serious poisoning, especially in children.
Symptoms of excessive boron intake include nausea, vomiting, diarrhea, skin rashes, and lethargy. The 20 mg per day upper limit was derived largely from animal studies showing reproductive and developmental toxicity at high exposures, with a safety margin applied.
| Intake level | Context | Comment |
|---|---|---|
| ~1–3 mg/day | Typical US diet | Normal dietary exposure |
| 3–10 mg/day | Common supplement range in studies | Generally well tolerated short term |
| 20 mg/day | Adult Tolerable Upper Intake Level | Not to be exceeded without medical advice |
| Much higher | Accidental ingestion of borates | Risk of poisoning |
The upper limit is lower for children and adolescents, and pregnant women should not use boron supplements beyond what is in a standard prenatal formula without consulting a doctor.
Myth 4: Most people are boron deficient
There is no established clinical syndrome of boron deficiency in humans, and no standard blood test to diagnose one. Claims that "most people are deficient" therefore lack a solid basis, since deficiency cannot be defined without an established requirement.
What research does suggest is that low-boron diets, mostly those poor in fruits, vegetables, and nuts, may be associated with less favorable markers of bone and mineral metabolism. This argues for a better diet rather than for widespread supplementation.
- Prunes and dried apricots: among the richest everyday sources.
- Avocados and peanut butter: common in American diets and notable contributors.
- Beans and lentils: provide boron along with fiber and protein.
- Coffee and milk: modest amounts but consumed in large volumes.
The real gap is not in boron but in research. Well-designed long-term trials on boron and bone, joint, or hormonal health are still lacking, so firm statements in either direction should be treated with caution.
Conclusions of the editorial team
Boron's reputation as a testosterone booster rests on very small, short studies and is not supported by trials measuring muscle or strength.
Doses within the 3–10 mg range used in research appear safe short term, but the 20 mg daily upper limit should be respected.
A diet rich in fruits, vegetables, legumes, and nuts already provides meaningful amounts of boron for most people.
If this topic interests you, you may also like our articles on evidence behind "testosterone booster" ingredients, on magnesium and sleep, and on zinc for athletes.
References
- Naghii MR, Mofid M, Asgari AR, et al. Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. J Trace Elem Med Biol. 2011;25(1):54–58.
- Ferrando AA, Green NR. The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders. Int J Sport Nutr. 1993;3(2):140–149.
- Nielsen FH, Hunt CD, Mullen LM, Hunt JR. Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women. FASEB J. 1987;1(5):394–397.
- Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press; 2001.
- Pizzorno L. Nothing boring about boron. Integr Med (Encinitas). 2015;14(4):35–48.
- Green NR, Ferrando AA. Plasma boron and the effects of boron supplementation in males. Environ Health Perspect. 1994;102(Suppl 7):73–77.
