Aromasin is a powerful estrogen blocker used as part of a Post Cycle Therapy (PCT) program. It can help restore your testosterone levels and protect your gains when used correctly. In addition to its benefits for PCT, Aromasin can also be used on cycle to help protect you from the side effects of estrogenic compounds, such as gynecomastia and water retention. Aromasin is a strong inhibitor that is effective at lower doses. It is more effective than Arimidex at preventing gynecomastia. Aromasin works by permanently binding to the aromatase enzyme, while Arimidex only binds for a short period. As a result, it is less likely to cause resistance, while Arimidex may be more likely to cause resistance over time.