What is Anastrozole?
Anastrozole (brand name Arimidex) is a non-steroidal, reversible aromatase inhibitor. It blocks the aromatase enzyme that converts testosterone to estradiol. In anabolic research contexts it is used to control estrogen side effects from aromatizing compounds (e.g. testosterone).
This information is for research and educational purposes only. No medical advice.
How it works
Anastrozole binds reversibly to aromatase and thereby lowers blood estradiol by up to 80%. Less estradiol means less water retention and a lower gynecomastia risk. Reversible means: after stopping, aromatase activity normalizes again.
Use and dosing
Members only
Dosing recommendations are visible to logged-in members only. Logging in is free.
What the research shows
The large ATAC study (Lancet Oncology, 2008) compared anastrozole with tamoxifen in postmenopausal early breast cancer over 100 months and established the long-term efficacy and tolerability of anastrozole. That is the clinical basis from which the estrogen-lowering potency is well documented.
Side effects
- Too-low estradiol: joint pain, libido loss, fatigue, poor sleep - the most common problem with overdosing.
- Lipids: very low estradiol worsens the cholesterol profile.
- Bone density: relevant with long-term use.
Storage
Store dry and protected from light. Out of reach of children.