The benefits of testosterone replacement therapy—and when and how much they affect you—differ from one individual to the next. However, the first benefits men tend to see are improved sleep quality and increased libido, usually noticeable as soon as week 4 of treatment. In subsequent weeks, most men report improved focus and clarity, increased energy levels, better mood and even improved muscle mass. It has, however, taken six weeks or more for some men to start noticing the benefits of treatment, so it’s important to not get discouraged.