Aromasin 25mg (Exemestane)

Aromasin (Exemestane) 25mg is a suicidal (irreversible) aromatase inhibitor that permanently deactivates the aromatase enzyme, preventing testosterone from converting to oestrogen during steroid cycles. Unlike Arimidex (which temporarily binds to the enzyme and can cause oestrogen rebound when discontinued), Aromasin destroys the enzyme entirely. The body must produce new aromatase before oestrogen levels rise again, providing more stable and predictable oestrogen control throughout your cycle.

When You Need an Aromatase Inhibitor

Any steroid that aromatises (converts to oestrogen) can cause water retention, bloating, elevated blood pressure, mood swings, and gynecomastia. The primary aromatising compounds are Testosterone (all esters), Dianabol, Deca-Durabolin, and Equipoise (at higher doses). If you are running any of these, you need an AI on hand. Non-aromatising compounds like Anavar, Winstrol, Trenbolone, and Masteron do not require oestrogen control from this compound.

The goal is not to eliminate oestrogen. Oestrogen plays important roles in joint health, lipid metabolism, bone density, and even muscle growth (it contributes to IGF-1 production). Crashing oestrogen too low causes dry joints, fatigue, low libido, depression, and lethargy. The aim is to keep oestrogen within a manageable range, using bloodwork (serum oestradiol test) at mid-cycle to fine-tune your dose.

Suggested Protocol

• Standard on-cycle dose: 12.5mg every other day (half a tablet). Adjust based on symptoms or bloodwork
• High-aromatising cycles (Dbol + Test): 25mg every other day
• Take with a fat-containing meal: absorption improves by up to 40% when taken with dietary fat
• No taper needed: suicidal AIs do not cause oestrogen rebound. You can stop without tapering

Aromasin vs Arimidex: Which Should You Choose?

• Aromasin (this product): suicidal AI (permanent enzyme destruction). No oestrogen rebound when stopped. Mildly beneficial for lipid profiles. Slightly increases IGF-1. The newer and generally preferred option
• Arimidex: competitive AI (temporary enzyme binding). Possible oestrogen rebound if stopped abruptly (taper recommended). Slightly harsher on cholesterol. More widely available and studied. Lower cost
• Verdict: Aromasin is preferred for longer cycles and users prone to oestrogen rebound. Arimidex is equally effective for users who manage their taper properly

Key Facts

• Active ingredient: Exemestane 25mg per tablet
• Class: Steroidal aromatase inhibitor (suicidal/irreversible)
• Half-life: approximately 24 hours
• Oestrogen reduction: approximately 85% at 25mg/day
• Absorption: 40% higher with fatty food
• Rebound risk: none (suicidal mechanism)

For complete side-effect management across all compounds, read our Steroid Side Effects Guide. For PCT after your cycle, see our PCT Guide. Browse all cycle support products.