The timeline for experiencing the benefits of testosterone replacement therapy can vary from individual to individual, as it depends on various factors, such as the severity of the testosterone deficiency, the treatment protocol, and the individual's response to the therapy.In general, many patients begin to notice improvements in energy, mood, and sexual function within the first few weeks of starting testosterone replacement therapy. However, it may take several months to see the full benefits, including improvements in muscle mass, strength, and overall physical performance.