Does boron raise your testosterone?

Two randomised controlled studies in male bodybuilders (19 participants combined) showed that 2.5 mg of boron per day for seven weeks did nothing for testosterone, muscle mass or strength compared with placebo. Both groups did improve, but that was due to the training itself, not to boron.

The only study that reported a significant rise in free testosterone in men used 10 mg per day in just eight men with no placebo group. After one week, the protein that binds testosterone and renders it inactive dropped significantly, leaving more active testosterone available in the blood. Without a comparison group, this result is hard to evaluate: it may be due to chance.

In women the picture is equally divided. An early study in postmenopausal women observed a noticeable rise in testosterone after switching from a very low intake to 3 mg of boron per day. However, a replication study with a comparable design found no effect whatsoever on those same hormones. The researchers suspected that the overly strict baseline diet had muddied the results, but that does not resolve the contradiction.

At higher doses (10 mg/day) in healthy men, oestradiol rose clearly, whereas testosterone showed only a non-significant upward trend. All in all, the evidence consists of contradictory results, small groups and missing placebo controls. Boron as a testosterone booster currently has no solid foundation.