Nipple sensitivity is a common experience for men starting Testosterone Replacement Therapy (TRT). This sensitivity usually occurs due to fluctuations in hormone levels, particularly the increase in testosterone and its conversion to estrogen.

During the first few months of TRT, your body adjusts to the higher levels of testosterone, which can temporarily elevate estrogen levels as well. This can lead to increased sensitivity in the nipples, as the breast tissue is responsive to estrogen.

This sensitivity is typically normal and expected during the initial stages of TRT. As hormone levels stabilise over time, this symptom often diminishes and resolves on its own within 2-3 months.

This sensitivity can even occur when estrogen levels are low, due to the hormonal fluctuations of starting TRT.

However, if nipple sensitivity persists beyond the 2-3 few months, it could indicate that estrogen levels remain elevated. In such cases, it's essential to address the issue to prevent potential complications like gynecomastia (the development of breast tissue in men).