Anabolic steroids – uses, how they work and side effects

1st February, 2022 • 8 min read

Anabolic steroids can be prescribed by a doctor to help treat a handful of medical conditions. Used as prescribed, they’re a safe and effective treatment for people dealing with sometimes complex conditions. They’re also often used illegally, without medical advice, and in dangerously high and addictive doses by athletes, including bodybuilders and weightlifters, to build muscle and improve performance.

Here’s what you need to know about the legal medical uses for anabolic steroids, how they work and the dangers of taking them without medical advice.

What are anabolic steroids?

Anabolic steroids (also called anabolic androgenic steroids, Arnolds, roids or stackers) are man-made. They work by copying some effects of the hormone testosterone, which your body produces naturally.

Testosterone is sometimes known as the ‘male’ hormone, but everyone’s bodies make it. During

, increases in testosterone in males causes facial and body hair growth, height development and voice deepening. It can also make you more competitive or more aggressive, and boost your
sex drive
and build muscle mass. It also has an important role in women, contributing to sex drive, helping maintain muscle and
bone strength
and playing a part in
and cognition.

Anabolic steroids are not the same as

, which are steroids used to treat conditions that cause inflammation. These can come as
steroid tablets
steroid creams
steroid injections
steroid nasal sprays

When would a doctor prescribe anabolic steroids?

In most countries, anabolic steroids should only be sold by pharmacists if you have a prescription. Used under medical supervision, and at the right doses, anabolic steroids can be a safe form of treatment.

If your doctor has prescribed a type of anabolic steroid, it will be to help treat a specific medical condition. For example, your doctor may recommend a legal course of anabolic steroids to help treat:

  • delayed puberty
  • hormone-related conditions – such as hypogonadism, when the body doesn't produce enough testosterone naturally, or symptoms of the
    , such as low sex drive (
  • conditions that lead to muscle loss, such as
    and stage 3
    HIV and AIDS

The doses and drugs are often different from what is used illegally and, with support and supervision, the risks are far lower. If you've read about the dangers of recreational steroids and you’re concerned, speak to your doctor. They’ll be able to reassure you that taking anabolic steroids for medical treatment does not carry the same level of risk as taking them for unsupervised non-medical purposes.

What are the different types of anabolic steroids?

You can get anabolic steroids as creams and gels, but the most common types are taken by mouth or injected into the muscle.

Anabolic steroids that you swallow as tablets include:

  • fluoxymesterone
  • mesterolone
  • methandienone
  • methyltestosterone
  • stanozolol

Injectable forms of anabolic steroids include:

  • boldenone undecylenate
  • methenolone enanthate
  • nandrolone decanoate
  • nandrolone phenylpropionate
  • testosterone cypionate

How do anabolic steroids work?

Once injected or swallowed, anabolic steroids are absorbed into the bloodstream and sent to the muscle tissue. Here, they mimic the effects of the natural version of testosterone produced by your body. This boosts cell growth in your muscles, which helps build and repair muscle.

Illegal uses of anabolic steroids

It’s common for anabolic steroids to be used without medical supervision – often in doses 10 to 100 times higher than would be prescribed by a doctor.

When they’re used in this way, anabolic steroids can cause serious side effects, including life-threatening medical conditions. They can also be addictive. Their use is banned by many sports organisations and, in many countries, they’re illegal without a prescription.

Anabolic steroids are often taken by athletes to:

  • improve performance
  • increase muscle mass
  • lose body fat
  • reduce recovery time

To help maintain muscle mass and because they think it will minimise side effects from larger doses, people who use anabolic steroids without medical advice often take them in 1 of 4 ways.

However, there’s no evidence that any of these methods reduce side effects.

  • cycling – anabolic steroids are sometimes taken in cycles, usually in a 6 to 12-week period, with 4 weeks (or several months) off after that
  • stacking – when people mix different types of steroids and supplements together because they think it will make them more effective
  • plateauing – when people alternate, overlap or substitute the drugs they use to stop their body getting used to them
  • pyramiding – when people gradually increase the dose and then reduce it to give their body a break

What are the side effects of anabolic steroids?

As with all medicines, anabolic steroids can cause side effects, even when you’re following medical advice.

However, taking anabolic steroids for non-medical reasons at much higher doses than your doctor would prescribe can lead to more serious side effects than steroids taken under supervision.

That means the following side effects may apply to anyone taking anabolic steroids, but they may be worse if you’re not taking a prescribed dose for a medical condition.

Common side effects in males include:

Common side effects in females include:

  • facial and body hair growth
  • loss of breasts
  • swelling of the clitoris
  • a deeper voice
  • a higher sex drive (libido)
  • problems with periods
  • hair loss
  • very bad acne

More serious side effects and medical conditions can also develop after taking anabolic steroids. These include:

Injecting anabolic steroids comes with extra risks if needles are shared, potentially leading to vein damage, ulcers or

hepatitis B
hepatitis C,
HIV transmission


Anabolic steroids can be addictive and result in withdrawal symptoms when you stop taking them. This is true whether you’re taking them under medical supervision or not.

Either way, it’s likely you’ll need to gradually reduce the dose over a number of weeks to prevent withdrawal symptoms. Note that non-prescription doses taken without medical supervision tend to be much higher, so the withdrawal effects are likely to be more severe.

Coming off anabolic steroids suddenly may cause:

When to see a doctor

You should always see a doctor before taking anabolic steroids.

If you do take them – with or without medical advice – and you’re worried about side effects, speak to your doctor as soon as possible.

You should also speak to a doctor if you think you’re addicted to them.

Signs that you may be addicted to anabolic steroids

  • you keep wanting to take steroids even if you have unpleasant side effects
  • you’re craving the drug and you need to take more to get the effect you’re after
  • you’re spending a lot of time and money taking steroids
  • you experience withdrawal symptoms when you stop them

Extra advice and support

You may find it helpful to speak to a drugs counsellor for advice on safely breaking the habit.

Your health questions answered**

Can anabolic steroids cause male infertility?

Answered by:

Healthily’s medical team

“One of the most common side effects of anabolic steroids is male infertility. Some studies suggest that sperm numbers may return to normal levels when anabolic steroid use is stopped. However, this isn’t guaranteed, and the quality of your sperm may be affected for longer than this – it may depend on factors such as how long you’ve been taking the steroids.”

Is creatine a steroid?

Answered by:

Healthily’s medical team

“No, they are very different substances – but both are sometimes taken to boost muscle mass and improve performance. Anabolic steroids are man-made and mimic the effects of testosterone production in the body. Creatine is a natural acid that’s made in the body and supplies energy to cells. It’s also found in foods such as red meat and fish, and can be taken as a supplement.”

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.