Supplement
Boron
Bone density and steroid hormone markers.
Grade D, tested: a human randomized trial looked for a benefit on the endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score. graded and did not find one. How to read a grade →
Boron is a trace mineral found in fruits, nuts and vegetables. It is sold for bones and for testosterone. In small studies, boron pills did not raise testosterone, muscle or strength over 7 weeks. They did not change bone density over 10 months. No study has looked at fractures or other health outcomes.
- Dose studied
- 3–10 mg/day
- Form graded
- Boron citrate/glycinate
- Cited PMIDs PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed.
- PMID 32540741 →
A letter describes the human evidence, not the product, the manufacturer, or the ingredient's worth.
See the full evidence record →This was not skipped. A human randomized trial has tested it and did not find a benefit on the endpoint below. That is a different statement from an untested intervention, which may still turn out to work. A Route 1 No human randomized trial has been run, so the record rests on animal or mechanistic evidence only. One of the two routes to the lowest letter on EBL's scale. Grade D means nobody has looked. A Route 2 Grade D means somebody looked and the answer was no.
Population 19 male bodybuilders aged 20 to 27, 2.5 mg/day for 7 weeks
Certainty Low. Small controlled trial (PubMed types it as a clinical trial, not a randomized one); null.
PMID 8508192 →
Population 28 female college students, 17 athletes and 11 sedentary, one year
Certainty Low. Small controlled trial (PubMed types it as a clinical trial, not a randomized one); no boron effect.
PMID 7889886 →
Population Healthy postmenopausal women in a metabolic unit, low-boron diet for 3 weeks then boron 3 mg/day for 3 weeks
Certainty Low. Small crossover-style metabolic study; no effect on any measure; the low-boron diet appeared to induce calcium hyperabsorption, which may have obscured an effect.
PMID 8329361 →
Boron for bone and steroid-hormone markers, graded on published human trial evidence.
Why this gradeGrade D, tested, no benefit. The reasoning, and what the grade does not cover.
Grade D, Route 2. Small randomized trials of boron found no effect on testosterone or lean mass (PMID 8508192) or on bone mineral density (PMID 7889886), and no trial reports a clinical outcome. Moved from Route 1 in October 2026; the letter is unchanged.
WHAT THIS GRADE DOES NOT COVERboron as a trace element in an ordinary diet, correction of a low dietary boron intake, and any outcome other than the hormone and bone markers those small trials measured.
A grade describes the human evidence for a named use. It is not advice, and it is not a judgment on any individual prescription. How the letters are decided →
Who responds: this record's trial reading reports no subgroup that identifies who responds.
How this letter has changed · latest: October 2026 · Corrected
The best-use line implied the question was untested; the small controlled trials exist and were null, now stated: Ferrando 1993 (PMID 8508192) and its second report Green 1994 (PMID 7889885), Meacham 1994 (PMID 7889886), and Beattie 1993 (PMID 8329361), added. The steroid-hormone claim is traced to Nielsen 1987 (PMID 3678698), a non-randomized study of 12 women, cited as context. Rondanelli 2020 (PMID 32540741) is described as a narrative review whose conclusion rests on non-randomized studies, with two authors at a commercial ingredient company's research unit. Letter unchanged.PMID 8508192 PMID 7889885 PMID 7889886 PMID 8329361 PMID 3678698 PMID 32540741
Every change to a letter on this site is dated and published. The full evidence log →
Commercial disclosure
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No dispensary link. EBL’s practitioner dispensary does not carry this item, so there is nothing to link to. Its absence is not a judgment beyond the letter above.
No dose is published here. This record carries no authored dose, because the cited trials do not converge on a single figure. Each trial cited on this page states the dose it used, and EBL has not turned those into a recommendation.
Standardized extracts were used in the cited trials; product quality varies.
The cited review does not report when doses were taken (PMID 32540741).
Checked against the published summary; the full paper could not be read. What the cited trials did, not a schedule. Every supplement, by trial timing →
Pregnancy: boron crosses the placenta and reproductive toxicity is the basis of the regulatory upper limit. Hormone-sensitive conditions, on the effect on sex-hormone levels.
Hormonal medication, including estrogen therapy: boron raises free testosterone and oestradiol in small human studies, so the effect is additive. Magnesium and riboflavin absorption are altered modestly. No prominent drug interaction otherwise.
The hormone claim comes from a small human supplementation study. The record says boron raises free testosterone and oestradiol in small human studies, which makes it additive with hormonal medication. A controlled human study of daily and weekly boron supplementation measured plasma steroid hormones and inflammatory cytokines directly, which is the source of that claim. It is small, in healthy volunteers, and short. Nobody has given boron to a person on estrogen therapy or any other hormonal medication and measured the result, so additivity is an inference from a hormone movement in untreated people. The magnesium and riboflavin absorption note on the same record is a nutrient-handling observation and is unmeasured against any drug. Naghii et al. (J Trace Elem Med Biol, 2011;25(1):54-8; PMID 21129941): comparative human study of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines.
Small randomized trials of boron on hormone and bone markers were null, and none reports a clinical outcome. If supplementing for bone health, track DEXA bone density at baseline and 12 months: this is the most plausible endpoint mechanistically, though no boron RCT Randomized controlled trial: people are assigned to the treatment or a comparison by chance, so the groups differ only in what they received. It is the design that can show cause and effect. has used it as a primary outcome. Serum boron levels are not a validated clinical marker.
Primary evidenceSix papers, each linked to its PubMed record.
Controlled trials, all null: Ferrando and Green (Int J Sport Nutr, 1993; PMID 8508192) and the same 19-subject trial reported again by Green and Ferrando (Environ Health Perspect, 1994; PMID 7889885), boron 2.5 mg/day for 7 weeks in male bodybuilders, no effect on testosterone, lean mass or strength (both groups improved with training); Meacham et al. (Environ Health Perspect, 1994; PMID 7889886), 3 mg/day for 10 months in 28 college women, bone density change not improved by boron; Beattie and Peace (Br J Nutr, 1993; PMID 8329361), postmenopausal women in a metabolic unit, a low-boron diet then 3 mg/day, no effect on minerals, sex steroids or bone-turnover markers. The claim behind the supplement: Nielsen et al. (FASEB J, 1987; PMID 3678698), a non-randomized metabolic-unit study of 12 postmenopausal women in which 3 mg/day after a low-boron diet raised serum estradiol and testosterone; context, not grade evidence. Rondanelli et al. (J Trace Elem Med Biol, 2020; PMID 32540741): narrative review of 11 human supplementation studies concluding 3 mg/day supports bone health; its conclusion rests largely on non-randomized metabolic studies, and two of its authors work in the research unit of a commercial botanical-ingredient company. Grade D, Route 2: the controlled trials found no effect, and no trial reports a clinical outcome.
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These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. The grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Starting, stopping or changing any supplement or medication is a decision for your physician.
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