Ancillary / Aromatase Inhibitor

Anastrozole (Arimidex)

Non-steroidal reversible aromatase inhibitor. FDA-approved for breast cancer. Reduces oestradiol. Used on TRT/AAS to control oestrogen. ⚠️ Overdosing causes oestrogen crash — worse than high oestrogen.

Build protocol outline Open dose calculator TNHL ebooks

Educational reference only. This page does not diagnose, prescribe, or replace care from a licensed professional. Laws, availability, and clinical appropriateness vary by location.

Reference dose0.25–1 mg every other day (always titrate to bloodwork)

Half-life46 hours

Risk flagmoderate

Regulatory noteFDA-approved context noted

Side effects and watch-outs

⚠️ Oestrogen crash if overdosed — joint pain, libido loss, depression, bone density loss, cardiovascular risk
Joint pain/stiffness
Hot flushes
Mood changes and depression
Bone density reduction with chronic use
HDL reduction
Fatigue
⚠️ Drug interaction: Tamoxifen reduces Anastrozole levels by ~27% — avoid combining