Estradiol (E2) is the primary form of estrogen. In men, a small amount of testosterone is converted into estradiol. A "sensitive" test is used for more precise measurements of low concentrations.
Purpose: While estrogen is often associated with female hormones, it plays important roles in male health, including erectile function, libido, and bone density. When testosterone levels rise during TRT, estradiol can also increase. Elevated E2 in men can cause side effects such as breast tissue growth (gynecomastia). Monitoring sensitive E2 helps manage this hormonal balance.