As ads warning against “low T” or “low testosterone” have proliferated, more and more men have begun treatment with testosterone, according to a study published in March 2017 in JAMA.

Men who use testosterone patches, tablets, injections, and gels hope to boost their energy and sex drive, but an editorial that accompanied the JAMA study warned that “the opportunities for overdiagnosis are substantial.” And according to the Food and Drug Administration (FDA), testosterone therapy has a possible link to an increased risk of heart attack and stroke.

On the occasion of National Men’s Health Week, test your knowledge: How much do you really know about testosterone?