Boron is in a lot of testosterone boosters because of one small study. Here's what that study measured, what other research found, and how much boron is safe.
One 2011 study of eight men found higher free testosterone and lower estradiol after a week of 10 mg boron a day, but it had no placebo group and lasted only a week. A placebo-controlled trial in bodybuilders found no testosterone effect. Boron is low-risk at a few milligrams a day, the adult upper limit is 20 mg, and it is not a fix for low testosterone.
Boron is a trace mineral found in fruit, vegetables, nuts, legumes and coffee. It shows up in a lot of testosterone boosters because of one small 2011 study that reported higher free testosterone after a week of 10 mg a day. That study is real, but it was tiny, short and uncontrolled, and a placebo-controlled trial in young men found no testosterone effect at a lower dose.
So the honest answer is that boron might nudge free testosterone and estrogen in the short term, but nobody has shown it produces a meaningful, lasting rise in testosterone or any noticeable benefit for men. It is also one of the few booster ingredients with a clear official upper limit, which matters if you stack several products.
The study behind most boron marketing was run by Naghii and colleagues and published in the Journal of Trace Elements in Medicine and Biology in 2011. An abstract of the same work describes the design: eight healthy male volunteers took a 10 mg boron capsule, with blood drawn on day 0, through the first day, and again after a week of 10 mg daily.
After one week, the researchers reported:
The authors described it as the first human study to report higher plasma free testosterone after boron. That line is why the study gets quoted so often.
The 2015 review "Nothing Boring About Boron" is often cited alongside it. That review is enthusiastic, but it is a narrative review by a single author, and the human hormone studies it describes have between 8 and 18 participants. It even reports the dose for the Naghii study inconsistently in different places.
Earlier work points the other way. In a 7-week trial published in Environmental Health Perspectives in 1994, Green and Ferrando gave 10 male bodybuilders 2.5 mg of boron a day and 9 others a placebo. Testosterone rose in both groups, which the authors put down to training. Boron had no significant effect on testosterone or any other variable they measured.
That trial was also small, and 2.5 mg is a lower dose than the 10 mg used later. Still, it had a placebo group, ran seven weeks instead of one, and studied young, active men, the same people most boron boosters are marketed to.
| Naghii et al. (2011) | Green and Ferrando (1994) | |
|---|---|---|
| Participants | 8 healthy men | 19 male bodybuilders |
| Dose | 10 mg a day | 2.5 mg a day |
| Length | 1 week | 7 weeks |
| Placebo group | No | Yes |
| Testosterone result | Free testosterone up, estradiol down | No effect of boron |
A 2019 analysis of 50 testosterone booster products in the World Journal of Men's Health found boron in about a quarter of the products it checked. The authors classed the published boron data as mixed, with some studies showing an increase and others showing no change.
There is no recommended daily amount for boron. According to the NIH Office of Dietary Supplements boron fact sheet, the data weren't strong enough to set one. What does exist is a Tolerable Upper Intake Level (UL), the most you should take daily from all sources combined:
| Age group | Upper limit per day |
|---|---|
| Adults 19 and older (including pregnancy and breastfeeding) | 20 mg |
| Teens 14 to 18 (including pregnancy and breastfeeding) | 17 mg |
| Children 9 to 13 | 11 mg |
| Children 4 to 8 | 6 mg |
| Children 1 to 3 | 3 mg |
The fact sheet says these limits are based on reproductive and developmental effects seen in animals. For context, it puts typical US adult intake from food at roughly 0.9 to 1.4 mg a day, mostly from coffee, milk, apples, beans and potatoes. A 10 mg supplement is therefore around seven to ten times what most people get from diet, while still under the adult limit.
Serious boron poisoning mostly comes from swallowing boric acid or borax, not supplements. The ODS lists symptoms of toxicity including nausea, vomiting, diarrhea, skin flushing and rash, headache, and in severe cases kidney injury and convulsions. There are no good data on long-term use at supplement doses, which is a reason to stay well under the limit rather than near it.
The ODS says boron isn't known to have clinically relevant interactions with medications, but that reflects limited research rather than proof of safety. Tell your doctor or pharmacist about it like any other supplement.
Boron tends to be sold alongside zinc and magnesium, and the logic for all three is similar: correcting a shortfall may help, while megadosing on top of a normal intake is unlikely to do much. Our guide to the connection between zinc and testosterone covers when zinc matters, and our magnesium supplement guide explains forms and sensible doses.
If you're thinking about boron because you feel tired, flat or have a lower sex drive, get the cause checked first. Those symptoms overlap with sleep problems, stress, weight and many medical conditions. Our guide to low testosterone symptoms in men explains what proper testing involves. A supplement can't fix diagnosed testosterone deficiency, and taking one instead of getting tested can delay finding something that matters.
If you do want to try boron, a few practical points:
The famous boron study found higher free testosterone and lower estradiol in eight men after one week of 10 mg a day. It's an interesting signal, but it had no placebo group, and a placebo-controlled trial in bodybuilders found no testosterone effect. Boron is reasonably safe at a few milligrams a day and has a clear adult upper limit of 20 mg. Treat it as a cheap, low-stakes experiment at most, not a fix for low testosterone.