A steroid is a type of chemical that occurs naturally in the body and helps control important functions like growth, healing, and energy. Your body makes steroids like cortisol, which helps you handle stress, and testosterone, which aids in muscle development and other changes during puberty.

Scientists have also created synthetic steroids as medicines. Doctors prescribe steroid medications to reduce dangerous swelling, treat asthma attacks, or help patients recover from serious illnesses. These medical steroids, when used properly under a doctor's care, can be lifesaving.

However, some athletes illegally use a specific type called anabolic steroids to build muscle mass faster and gain an unfair advantage in competition. This kind of steroid abuse is considered cheating in sports and can cause serious health problems, including heart damage, mood swings, and stunted growth in young people. Sports organizations ban these steroids and test athletes to catch cheaters.

The word appears in other contexts too. When doctors give you a steroid shot for a bad rash or allergic reaction, they may be using a different type of steroid that reduces inflammation. Understanding the difference matters: medical steroids used correctly help people heal, while performance-enhancing steroids represent both cheating and a serious health risk.