Technically called anabolic-androgenic steroids (AASs)Trusted Source, steroids are a type of artificial testosterone. They can be taken as a supplement to replace or add to your body’s natural levels of testosterone.

Testosterone (T) is a hormone typically associated with the male body. The average male has about 300 to 1,000 nanograms per deciliter (ng/dL) of this hormone in their body.

Testosterone is most known for causing changes to the male body during puberty, making the voice deeper and the body hairier. It also increases sperm production in the testicles.

The female body also produces TTrusted Source. But it’s usually found in smaller amounts, where it’s used to keep bones strong and sexual function healthy.

And having testosterone levels that are higher than normal, such as through use of steroids, can help create proteins that are used to support:

• muscle growth
• hair growth
• sexual functions
• bone density

That’s why steroids are associated with athletes like bodybuilders. It’s thought that the more anabolic steroids you take, the more potential for strength and muscle growth you have. That’s why you may hear these referred to as performance-enhancing drugs (PEDs).

Steroids aren’t always harmful when used appropriately. They’re used for a variety of both health and athletic purposes, including:

• gaining body mass from more protein production in the body (about 4.5 to 11 pounds)
• lowering your overall body fat percentage
• gaining muscle strength and endurance
• increasing how dense your bones are
• increased red blood cell production
• improve performance in strength-related sports, such as weightlifting
• “stacking” steroids with other substances, such as growth hormones and insulin, for increased muscle mass
• maintaining muscle mass when you have a condition like liver disease or cancer that causes your muscles to waste away

In small doses for short amounts of time, when their use is monitored by a doctor, anabolic steroids have lower risk of long-term or harmful side effects.

Your genesTrusted Source can influence how steroids affect you.

There’s also a ratio of androgenic to anabolic components for most steroids:

• anabolic components help grow muscle
• androgenic components affect male sex traits like body hair or sperm production

But using high amounts of steroids, even for a short time, or using them for a long period can lead to numerous side effects, including:

• raising your risk of heart disease and heart attacks
• making you act more aggressivelyTrusted Source and impulsively
• making you feel worse about your body (body dysmorphiaTrusted Source)
• damaging your liver
• causing fat tissue to grow in your breasts (called gynecomastiaTrusted Source in men) because of a loss of hormone balance, especially if you stop taking steroids
• reducing how much testosterone your body makes naturally (hypogonadism), as your body gets used to the extra dose from steroids and stops producing as much
• reducing your chance of having childrenTrusted Source because of lower sperm production
• causing male-pattern baldness or making it start earlier in life

Side effects for women

Steroid use can have specific side effects in the female body in addition to the others listed above, including:

• deeper voice
• changes in face shape
• facial hair growth
• clitoris growing larger than normal
• period becoming irregular
• shrinking breasts
• infertility

Many people who use anabolic steroids recreationally take much more than is typically used for medical conditions. This is especially true if the steroids are in a supplement or injection that contains high concentrations.

The way they’re misused can make them dangerous too:

• cycling: using a large amount of steroids and then stopping for a while before using them again
• stacking: use multiple types of steroids at once, or using different delivery forms (like injections and supplements together)
• pyramiding: starting with small doses and then taking more and more, followed by reducing the amount again
• plateauing: changing to another steroid suddenly to keep the steroid from become ineffective and then switching back

Some people can become used to the feeling of strength or endurance that steroids give them and become dangerously addicted.