Testosterone is a typically male hormone that’s mainly produced in the testicles. If you’re a man, it helps your body develop sex organs, sperm, and sex drive.

The hormone also helps maintain male features such as muscle strength and mass, facial and body hair, and a deepened voice. Your testosterone levels typically peak in early adulthood and slowly decrease with age.

Topical testosterone is a prescription drug that’s applied to your skin. It’s used to treat hypogonadism, a condition that prevents your body from making enough testosterone.

The Food and Drug Administration (FDA) has approved topical testosterones in gel form. However, some men prefer compounded testosterone creams (where a pharmacy mixes testosterone with a creamy base), because they find them easier to use and less likely to be transferred by touch. Otherwise, the effects of gels vs. creams are not very different.

While topical testosterone can be helpful to men with hypogonadism, it can also cause unexpected topical and hormonal side effects.