Boron is a trace mineral that most American adults get at roughly 0.9 to 1.4 mg a day from food, and the government's tolerable upper intake level for adults is 20 mg a day. A handful of small human studies, at doses from 2.5 to 10 mg a day, have looked at boron and testosterone, with mixed results: one eight-man study saw free testosterone rise after a week at 10 mg a day, while a placebo-controlled trial in bodybuilders at 2.5 mg a day found no effect. Boron may play a role in hormone and mineral metabolism, but the evidence is early, small, and not enough to promise a testosterone increase.
Key takeaways
- Boron has no RDA. The Institute of Medicine set an adult upper limit of 20 mg/day in 2001.
- Typical U.S. adult intake from food is roughly 0.9 to 1.4 mg/day, with coffee, milk, apples, beans, and potatoes among the main sources.
- The best-known men's study (Naghii, 2011) gave 10 mg/day to 8 men for one week and reported higher free testosterone and lower estradiol. It had no separate placebo group.
- A 7-week placebo-controlled trial in 19 male bodybuilders at 2.5 mg/day found no effect on testosterone, lean mass, or strength.
- Boron has also been studied for calcium, magnesium, and vitamin D metabolism and for bone, but human evidence is limited.
What is boron?
Boron is a trace element found in soil, water, and plant foods. It is essential for plants, but no clearly defined biological function has been established in humans, which is part of why there is no official requirement. Even so, boron appears to interact with how the body handles several hormones and minerals, including estrogen, testosterone, vitamin D, calcium, and magnesium.
Food sources of boron
Plant foods such as fruit, legumes, and nuts supply most dietary boron. According to the NIH Office of Dietary Supplements, approximate amounts per serving include:
- Prune juice, 1 cup: about 1.4 mg
- Avocado, 1/2 cup: about 1.1 mg
- Raisins, 1.5 oz: about 0.95 mg
- Peach, 1 medium: about 0.8 mg
- Apple, 1 medium: about 0.7 mg
- Peanuts or peanut butter, 1 oz or 2 tbsp: about 0.5 mg
- Refried beans, 1/2 cup: about 0.5 mg
In the U.S., coffee, milk, apples, beans, and potatoes supply much of the boron people eat, mainly because they are consumed so often.
How much boron per day?
There is no Recommended Dietary Allowance, Adequate Intake, or Daily Value for boron. When the Food and Nutrition Board of the Institute of Medicine reviewed the evidence in 2001, it concluded the data were not strong enough to set a requirement. It did set a Tolerable Upper Intake Level (UL) of 20 mg/day for adults 19 and older, based on reproductive and developmental effects seen in animal studies.
For context, median dietary intake among U.S. adults is about 0.87 to 1.35 mg/day, and total intake from food plus supplements is about 1.0 to 1.5 mg/day. Most of the human supplementation studies have used 2.5 to 10 mg/day, which sits between ordinary dietary intake and the UL.
What the research on boron and testosterone shows
The research below concerns boron as an ingredient, not any finished MAXIS product.
Interest in boron for men comes from a few small studies that measured sex hormones. Together, they suggest boron can influence hormone levels in some situations, but they do not show a consistent rise in testosterone.
The 1987 USDA study (postmenopausal women)
An early, widely cited study was done at the USDA's Grand Forks Human Nutrition Research Center. Twelve postmenopausal women lived in a metabolic unit and ate a diet supplying only about 0.25 mg of boron a day for 119 days, then received 3 mg/day of supplemental boron. Supplementation reduced urinary loss of calcium and magnesium and raised blood levels of both estradiol and testosterone. The participants were women who started from a deliberately boron-poor diet, so the findings do not translate directly to men eating a normal diet.
Bodybuilders, 2.5 mg/day (1993)
Ferrando and Green gave 10 male bodybuilders 2.5 mg of boron daily and 9 others a placebo for 7 weeks. Plasma boron rose in the supplemented group, but there was no significant effect of boron on total or free testosterone, lean body mass, or strength. Both groups improved, which the authors attributed to training. It is one of the few placebo-controlled trials in men, and its result was negative.
Healthy men, 10 mg/day for four weeks (1997)
Naghii and Samman gave healthy men 10 mg of boron daily for four weeks. About 84% of the dose was recovered in urine, suggesting boron is absorbed efficiently. Plasma estradiol increased significantly, while testosterone showed only a trend toward an increase.
Eight men, 10 mg/day for one week (2011)
The most cited study for "boron and testosterone" is Naghii and colleagues (2011). Eight healthy men took 10 mg of boron with breakfast daily for a week. Six hours after the first dose, sex hormone binding globulin (SHBG) and inflammatory markers (hsCRP and TNF-alpha) were lower. After one week, mean free testosterone was higher and estradiol was lower than at baseline, and dihydrotestosterone, cortisol, and vitamin D were higher.
It is worth being clear about the limits: eight participants, one week, and no parallel placebo group (the comparison was against the same men's earlier samples). Results like this are a reason for further research, not proof of an effect.
| Study | Participants | Boron dose | Duration | What was measured | Main hormone finding |
|---|---|---|---|---|---|
| Nielsen et al. (1987) | 12 postmenopausal women | 3 mg/day after a low-boron diet (~0.25 mg/day) | Low-boron diet for 119 days, then supplementation | Urinary minerals, serum estradiol and testosterone | Estradiol and testosterone rose |
| Ferrando & Green (1993) | 19 male bodybuilders (10 boron, 9 placebo) | 2.5 mg/day | 7 weeks | Total and free testosterone, lean mass, strength | No effect of boron |
| Naghii & Samman (1997) | Healthy men | 10 mg/day | 4 weeks | Urinary boron, lipids, steroid hormones | Estradiol rose; testosterone trend only |
| Naghii et al. (2011) | 8 healthy men | 10 mg/day | 1 week | Sex hormones, SHBG, inflammatory markers | Free testosterone up, estradiol down vs. baseline |
Notice that the studies do not even agree on direction for estradiol: it rose in the 1997 study and fell in the 2011 study. That inconsistency, along with the small samples, is why boron should be thought of as a nutrient that may support normal hormone metabolism rather than as a testosterone booster.
Boron's other studied roles: bone, vitamin D, and magnesium
Much of boron research is actually about minerals and bone. In the 1987 USDA study, boron reduced urinary loss of calcium and magnesium. According to the NIH, a very low-boron diet has been associated with lower blood calcium and vitamin D (25-hydroxyvitamin D) levels in men and women.
In a study of female college students, 3 mg/day of boron over roughly a year affected serum phosphorus and magnesium, but it did not have a clear effect on bone mineral density. Animal studies show that boron deficiency can impair bone development and strength. Overall, the NIH notes that human evidence is not sufficient to recommend boron supplements for bone health.
Safety and who should be careful
Boron from food and water has not been linked to adverse effects. Problems arise at much higher amounts, typically from accidental swallowing of boric acid or borax, which are household and industrial products, not supplements. Nausea, vomiting, diarrhea, skin rash, and in serious cases kidney injury have been reported, mostly in young children.
- Keep total intake from food and supplements under the 20 mg/day adult UL. Combining several products that each contain boron is the most likely way to overshoot.
- Children have much lower ULs than adults, so adult supplements are not for them.
- Because boron may affect estrogen and testosterone, check with your doctor before supplementing if you have a hormone-related medical condition, take prescription medication, or are pregnant or breastfeeding.
How 3 mg compares with the doses studied
A 3 mg daily dose is the same amount used in the 1987 USDA study and the female-athlete study, and a little above the 2.5 mg used in the bodybuilder trial. It is less than a third of the 10 mg/day used in the two Naghii studies. Added to typical intake of about 1 to 1.5 mg, 3 mg puts total daily boron at roughly 4 to 4.5 mg, well under the 20 mg UL.
Where MAXIS Men's Vitality fits
MAXIS Men's Vitality provides 3 mg of boron (from boron chelate) per serving of 2 vegan capsules, alongside:
- 15 mg zinc as L-OptiZinc® (see zinc methionine vs. other zinc forms)
- 500 mg Testosurge® fenugreek seed extract (80% glycosides) (see fenugreek and testosterone)
- 200 mg LongJax® long jack root extract
- 120 mg Shoden® ashwagandha root extract
- 100 mg Liboost® damiana leaf extract
Take two capsules daily, an hour before physical activity or bedtime. Men's Vitality is designed to support healthy testosterone levels already within the normal range.† It is not for anyone already taking a zinc supplement or Ashwagandha+.
FAQ
Does boron increase testosterone in men?
The evidence is mixed. One small study of eight men without a separate placebo group at 10 mg/day reported higher free testosterone after a week, while a placebo-controlled trial at 2.5 mg/day in bodybuilders found no effect. There is not enough evidence to say boron reliably raises testosterone.
How much boron per day is safe?
The adult upper limit set by the Institute of Medicine is 20 mg/day from all sources. Most U.S. adults get roughly 1 to 1.5 mg/day from food and supplements combined, and studies have generally used 2.5 to 10 mg/day.
What is the best boron supplement dosage for men?
There is no official recommended dose because boron has no RDA. Human studies in men used 2.5 to 10 mg/day for one to seven weeks. A 3 mg dose matches the amount used in several of these studies and stays far below the upper limit.
Can I get enough boron from food?
Everyone gets some from food; typical U.S. intake is about 0.9 to 1.4 mg a day. Eating more fruit, beans, nuts, and avocado raises intake; a cup of prune juice alone has about 1.4 mg.
References
- National Institutes of Health, Office of Dietary Supplements (2022). Boron: Fact Sheet for Health Professionals. ods.od.nih.gov
- Institute of Medicine, Food and Nutrition Board (2001). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. National Academies Press. nap.nationalacademies.org
- Nielsen FH, Hunt CD, Mullen LM, Hunt JR (1987). Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women. FASEB Journal. PubMed 3678698
- Ferrando AA, Green NR (1993). The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders. International Journal of Sport Nutrition. PubMed 8508192
- Naghii MR, Samman S (1997). The effect of boron supplementation on its urinary excretion and selected cardiovascular risk factors in healthy male subjects. Biological Trace Element Research. PubMed 9197924
- Naghii MR, Mofid M, Asgari AR, Hedayati M, Daneshpour MS (2011). Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. Journal of Trace Elements in Medicine and Biology. PubMed 21129941
- Meacham SL, Taper LJ, Volpe SL (1994). Effects of boron supplementation on bone mineral density and dietary, blood, and urinary calcium, phosphorus, magnesium, and boron in female athletes. Environmental Health Perspectives. PubMed 7889886
†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.
