Anabolic-androgenic steroids (AAS) are substances that copy the effects of testosterone, the main male sex hormone. They are the most commonly used drugs to improve appearance and performance. About 1.6% of women have used AAS, but it’s more common in groups like female bodybuilders and athletes.

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The information on this page and our study focus on AAS use outside of medical treatment. In the UK, testosterone is only prescribed in women in certain conditions such as low sexual desire in post-menopause or in transgender treatment. 

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AAS are man-made versions of testosterone and other natural hormones, like dihydrotestosterone and nandrolone, meant to copy the effects of testosterone. They come in pills, injections, or patches. The anabolic effect helps build muscle and strength, while the androgenic effect causes male traits. The androgenic effects can be harmful to women.

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The structure of AAS is changed to control how much they help build muscle or cause male traits. Some steroids are made to be taken as pills instead of injections, and to last longer. However, AAS are not tightly controlled, and studies show that about two-thirds of products might be fake or have different amounts than what’s listed on the label.

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​​​​​Some male AAS users take post-cycle therapy (PCT) to try to restart their body’s natural hormone production after using steroids. PCT includes drugs like clomiphene, tamoxifen, and human chorionic gonadotrophin (hCG). Even though many people use PCT, there is no proof that it works. There have been no studies to see if these drugs work in female AAS users. 

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​Women use AAS for similar reasons as men: to build muscle, get stronger, and lose fat. The internet is the main place people get information about AAS, but most of it is written by men and doesn’t talk about the specific side effects for women. This lack of information can leave women with the wrong ideas and unprepared for the side effects they might face.