Positive and negative side effects of androgen abuse. The HAARLEM study: A one‐year prospective cohort study in 100 men

An estimated 4‐6% of fitness center visitors uses anabolic‐androgenic steroids (AAS). Reliable data about adverse reactions of AAS are scarce. The HAARLEM study aimed to provide insight into the positive and negative effects of AAS use. One hundred men (≥18 years) who intended to start an AAS cycle on short notice were included for follow‐up. Clinic visits took place before (T 0 ), at the end (T 1 ), and three months after the end of the AAS...