What is anastrozole?
Anastrozole is an aromatase inhibitor medication that blocks the enzyme responsible for converting testosterone into estrogen, commonly prescribed alongside TRT to prevent unwanted side effects from elevated estrogen levels.
Anastrozole belongs to a class of drugs called aromatase inhibitors (AIs). When men receive testosterone replacement therapy, some of that testosterone converts into estrogen through an enzyme called aromatase. If this conversion goes unchecked, estrogen levels can climb, causing side effects like gynecomastia (breast tissue growth), water retention, mood changes, and reduced libido.
Anastrozole works by blocking aromatase activity, which keeps estrogen levels in a target range. This makes it one of the most frequently prescribed AIs alongside TRT protocols. Rather than eliminating estrogen entirely (which would be harmful), the drug maintains a balance between testosterone and estrogen that feels normal and avoids the symptoms of excess estrogen.
Dosing and frequency vary by individual response and the testosterone dose being used. Some men need it only occasionally, while others take it on a regular schedule. Providers often adjust the dose based on blood work showing estrogen markers. Anastrozole comes as an oral tablet, making it simple to administer alongside other TRT medications.
Because anastrozole directly impacts hormone balance, it should only be used under medical supervision from a qualified TRT provider who can monitor your hormone levels and adjust treatment as needed.