Letrozole
Femara. Most potent aromatase inhibitor. Reduces estrogen by up to 98%. Used for extreme estrogen control or gyno reversal attempts.
Overview
Femara. Most potent aromatase inhibitor. Reduces estrogen by up to 98%. Used for extreme estrogen control or gyno reversal attempts.
Dramatically lowers estradiol (can crash E2), significantly worsens lipids (estrogen is cardioprotective), can cause joint pain, fatigue, and mood issues from suppressed E2, may reduce IGF-1, can lower bone mineral density with prolonged use
Compound Guide
Mechanism: Third-generation non-steroidal aromatase inhibitor. Reversible binding. ~98% estrogen suppression at full dose — the most potent AI available.
Dosage:
- Emergency gyno flare: 2.5mg/day for 5-7 days, then taper to 0.5mg EOD
- Estrogen control (last resort): 0.25-0.5mg EOD (start very low)
- Gyno reversal protocol: 2.5mg/day for 7-10 days alongside Raloxifene 60mg/day
Administration:
- Oral tablet. Can be split/quartered for lower dosing
- Take with or without food
Key Notes:
- Should RARELY be used for routine estrogen management — too potent, too easy to crash E2
- Crashed estradiol symptoms: joint pain, fatigue, depression, zero libido, dry skin, brain fog
- Recovery from crashed E2 takes days to weeks depending on testosterone dose and aromatisation rate
- Anastrozole or Exemestane are preferred for routine estrogen management
- Reserve Letrozole for gyno flares or reversal protocols
- Worsens lipids significantly — estrogen protects cardiovascular health
- Monitor E2 levels closely if using Letrozole (sensitive LC-MS/MS assay preferred)
Usage History
Frequently Asked Questions
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Quick Reference
Category
AI
Half-Life
2 days
Detection Time
N/A