In men, low testosterone levels in the body can be supplemented by hormone replacement with testosterone. Testosterone replacement therapy can be prescribed as an intramuscular injection usually given on a biweekly basis; as a patch or gel placed on the skin, or as putty that is applied to the gums of the mouth. Each of the treatments has its risks and benefits. The decision as to which form of testosterone to use depends upon the clinical situation. Discussions between the patient and health care professional often helps decide which medication to use.
In the United States there are currently no preparations that are FDA approved for testosterone replacement for women.
But I'm not more aggressive—a behavior change often tied to testosterone. That's not surprising to Robert Sapolsky, ., a neuroendocrinologist at Stanford University and a leading researcher on stress and behavior. "It's really not the case that testosterone 'causes' aggressive behavior," he says. "Instead, it makes the brain more sensitive to social cues that trigger aggression. And in support of that, a guy's testosterone level isn't a very good predictor of how likely he is to be aggressive."