This is my second month of using Testim. I began at 50mg per day with remarkable increases in libido and performance within 3 days, along with an elevated mood and sense of well being. Three weeks into using Testim, my libido and performance dropped noticeably. On the suggestion of the forum and my doctor, I increased the dose of Testim to 100mg per day. Within the first week of increased dosage, libido, performance returned to a more comfortable level, although not to the level of the first two weeks. It seems that the natural production of testosterone and other hormones (luteinizing hormone, for example) shut down considerably soon after testosterone replacement therapy begins, thus causing I believe the sudden reduction of libido and performance after my second week or so. This suggests the need for some men to regulate the amounts, and maybe even the application sites and times to apply Testim. Hopefully over time the effects of Testim will level out and cause positive long term effects. Overall, my early assessment the product is highly favorable ....my current sense of feeling and acting "youthful" is great...for a 56 year old.