If used in this way, they can cause serious side effects and addiction. 

Anabolic steroids are manufactured medicines that copy the effects of male hormones, such as testosterone. They have limited medical uses and are not the same as corticosteroids, a different type of steroid medicine that's more commonly prescribed.

Anabolic steroids are class C medicines, which can only be issued by pharmacists with a prescription.

It's legal to have anabolic steroids for personal use. They can also be imported or exported, as long as this is carried out in person. This means they can't be posted or delivered by a courier or freight service.

However, it's illegal to possess, import or export anabolic steroids if it's believed you're supplying or selling them. This includes giving them to friends. The penalty is an unlimited fine, or even a prison sentence of up to 14 years.

In professional sport, most organisations ban anabolic steroid use and test competitors for banned steroids. If you do test positive, you may be banned from competing professionally.

Anabolic steroids can be used to enhance performance and increase muscle mass. Some people take them regularly to improve their physical performance and build up their bodies. But they can also have many undesirable effects.

People of all ages have been known to misuse these medicines, including adolescent boys who have body dysmorphic disorder. This is a mental health condition where a person spends a lot of time worrying about flaws in their appearance, which are often unnoticeable to others.

People who have body dysmorphic disorder may take anabolic steroids because they do not see themselves as being physically big enough or strong enough.

Some people believe taking anabolic steroids will help them become fit and healthy. This is not true: taking anabolic steroids is a dangerous habit.

Anabolic steroids are usually injected into a muscle or taken by mouth as tablets, but they also come as creams or gels that are applied to the skin.

Many people who use anabolic steroids are aware of the dangers and believe that by taking them in certain ways they can avoid side effects. Or they may take additional medicines to try to counter the side effects.

Users might:

• take anabolic steroids for a period of time and then stop for a rest period before starting again – this is known as "cycling"
• take more than 1 type of anabolic steroid or other performance-enhancing medicine at a time, known as "stacking", which they believe makes the steroids work better or will counter the side effects of the steroids
• do something called "pyramiding", sometimes used during the training period before a competition, where an athlete will start taking a low dose of 1 or more anabolic steroids and then increase the dose over time up to a maximum dose – they then reduce the dose in the period leading up to a competition to avoid detection during drug testing

But there is no evidence that any of these methods actually reduce the side effects and harms caused by taking anabolic steroids.

Users tend to exercise more when they're taking high doses to make the most of their improved performance during this time.

Regularly taking anabolic steroids can lead to physical and psychological changes in both men and women, as well as potentially dangerous medical conditions.

Physical effects

Effects of anabolic steroids in men can include:

• reduced sperm count
• infertility
• shrunken testicles
• erectile dysfunction (impotence)
• hair loss
• breast development
• increased risk of testicular cancer
• severe acne

In women, anabolic steroids can cause:

• excess growth of facial and body hair
• decreased breast size
• swelling of the clitoris
• a deepened voice
• an increased sex drive
• problems with periods
• hair loss
• severe acne

In addition, both men and women who take anabolic steroids can develop any of the following medical conditions:

• heart attack or stroke
• liver or kidney problems or failure
• high blood pressure (hypertension)
• deep vein thrombosis
• fluid retention
• high cholesterol

Psychological effects

Misusing anabolic steroids can also cause the following psychological or emotional effects:

• aggressive behaviour
• mood swings
• paranoia
• manic behaviour
• hallucinations and delusions

Stunted growth in adolescents

Anabolic steroids accelerate bone growth, so if they're misused by adolescents who have not yet had the growth spurt associated with puberty, they can cause premature ageing of the bones and restricted growth.

Sharing needles

As anabolic steroids are often injected, there are risks associated with sharing needles. These are the same risks associated with recreational drug use and include:

• damage to veins, leading to ulcers or gangrene
• hepatitis B infection
• hepatitis C infection
• HIV transmission

Anabolic steroids are addictive. This means you can crave them, require more to get the same effect and have withdrawal symptoms if you suddenly stop taking them.

A person who is addicted to anabolic steroids will want to keep using them despite experiencing unpleasant physical side effects.

When doctors prescribe steroid medicine, they may advise coming off it slowly by gradually reducing the dose.

Coming off anabolic steroids suddenly can result in withdrawal symptoms that include:

• depression and apathy
• feelings of anxiety
• difficulty concentrating
• insomnia
• anorexia
• decreased sex drive
• extreme tiredness (fatigue)
• headaches
• muscle and joint pain

You should see a GP if you think you're addicted to anabolic steroids. Treatment for an addiction to anabolic steroids will be similar to that of other types of addiction.

The GP may refer you to a specially trained drugs counsellor. They'll discuss your addiction with you, how to safely stop taking steroids and any obstacles you may face when trying to stop, plus tips for dealing with those obstacles.

Further information and advice:

• Drug addiction: getting help
• Find drug addiction support services
• Help and advice on the FRANK website