Anabolic steroids (AAS) are synthetic versions of testosterone that promote muscle growth and strength. Medically, they treat hormone deficiencies, muscle-wasting conditions, and delayed puberty. Bodybuilders and athletes often misuse them in high doses to rapidly build muscle and enhance performance. While effective, they carry serious risks including heart problems, liver damage, hormonal imbalance, infertility, aggression, and addiction. They are controlled substances in most countries and banned in sports.