Aromatase Inhibitor Timing

Aromatase inhibitors (AIs) control estradiol by blocking the enzyme that converts testosterone to estrogen. Timing them to your testosterone ester’s pharmacokinetics is the single most important — and most commonly mismanaged — aspect of cycle ancillary use.

Match the ester

A long ester (enanthate, cypionate, deca) builds estradiol slowly and persistently. An AI dosed to match (e.g., every 3–4 days) keeps estrogen stable. A short ester (propionate) spikes estradiol fast, requiring closer AI timing.

The over-suppression trap

The most common harm is crashing estradiol by over-dosing an AI. Low estradiol causes joint pain, libido loss, mood disturbance, and lipid damage — often worse than mildly high estrogen.

Anastrozole vs. exemestane vs. letrozole

• Arimidex (Anastrozole) — reversible, moderate potency.
• Aromasin (Exemestane) — suicidal (permanent enzyme inactivation), estrogen rebounds only as new enzyme is synthesized.
• Letrozole — most potent; reserve for stubborn high estradiol.

Plot any of these in the tool to see their relatively short half-lives — another reason dosing cadence matters.