Testosterone is popularly known as the hormone that makes men faster and stronger (and hairier), and also more prone to aggression and road rage. But testosterone plays a much wider and more significant role in the health of both men and women.  

In the past two decades, men’s health has become a big topic, and testosterone has captured lots of attention. In particular, the use of testosterone replacement therapy, known as TRT, has surged. What used to be a treatment for mostly older men suffering erectile dysfunction has turned into a large industry marketing TRT to men of all ages as a way to build more muscle, boost energy levels and libido, sharpen them mentally and generally make them feel better.

In response to the demand, so-called low-T clinics and other online men’s health clinics have proliferated. According to one study, direct-to-consumer men’s health websites increased their unique visits 1688%—a nearly 17-fold increase—between 2017 and 2019.