Testosterone aromatizes to estradiol via the aromatase (CYP19) enzyme in adipose tissue, muscle, and brain. Estradiol in men supports bone density, libido, cognitive function, and lipid metabolism. Too much estradiol during TRT can cause gynecomastia, water retention, and emotional lability. Anastrozole, a nonsteroidal aromatase inhibitor approved for breast cancer at 1 mg daily, appears in men's health at 0.25 to 0.5 mg compounded capsules as an adjunct to control estrogen when clinically indicated.
When estrogen management comes up
Not every man on TRT needs anastrozole. Indications include symptomatic gynecomastia, estradiol levels consistently above individualized targets on sensitive assays, or dose-limiting TRT increases where estradiol rises disproportionately. Routine crushing of estradiol to near-zero is outdated practice associated with joint pain, low libido, and bone loss.
Dosing philosophy
Telehealth protocols often use 0.5 mg anastrozole twice weekly or 0.25 mg every other day, far below oncology dosing. Goal is mid-range estradiol (commonly cited 20 to 40 pg/mL on sensitive LC/MS assays, lab-dependent), not elimination.
Risks of over-aromatase inhibition
- Decreased bone mineral density over years
- Unfavorable lipid changes
- Erectile dysfunction and mood flattening from too-low estrogen
- False confidence from labs that look "optimized" while symptoms worsen
Alternatives to anastrozole
Reducing TRT dose, splitting injections more frequently to reduce aromatization spikes, or losing visceral fat (major aromatase source) may solve estrogen issues without AI drugs. DIM and other supplements lack robust evidence compared to pharmaceutical aromatase inhibition.
CLYR Health offers anastrozole 0.5mg capsules as a TRT adjunct for patients whose providers determine selective estrogen management is clinically warranted.