Testosterone gel begins to increase serum testosterone levels quite rapidly, with measurable rises within 30 minutes and reaching steady-state levels by the second or third day of daily application

. However, the clinical effects take longer to manifest:

• Sexual effects such as increased libido may start to appear within about 3 weeks, with improvements in erections and sexual performance developing over 6 months

• Muscle mass and strength gains typically become noticeable after 12 to 16 weeks (3 to 4 months) of treatment, with continued improvements stabilizing around 6 to 12 months

• Changes in body composition (increase in lean body mass, decrease in fat mass) and metabolic benefits such as improved insulin sensitivity often take 3 to 12 months to become evident

• Other benefits like mood improvement and quality of life changes may begin within a few weeks but reach maximum effect over several months

In summary, while testosterone gel starts working on hormone levels within hours to days, most physical and functional effects typically require 6 to 12 weeks to start becoming noticeable , with full benefits often taking 4 to 6 months or longer depending on the individual and dosage