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24 February 2023

Gynaecomastia refers to the growth of breast gland tissue in boys and men. Gynaecomastia is often confused with the increase in adipose tissue in the chest area associated with gaining weight. In gynaecomastia, the increasing tissue is breast gland tissue and is firmer in structure. The changes are often benign, meaning there is no risk of breast cancer. [1, 2]

Gynaecomastia is a common ailment and is often associated with hormonal changes at different stages of life. It is most common in newborns, adolescents and older men. Anything that lowers testosterone and affects the production of oestrogen in a man’s body may cause gynaecomastia. Such causes include various diseases, lifestyle factors and pharmaceuticals. [1, 2, 3]

Gynaecomastia is one of the most common side effects caused by anabolic steroids. In several studies, up to a third of users have reported gynaecomastia caused by anabolic steroids. [4, 5] Unlike the gynaecomastia associated with normal growth and development in children, breast growth caused by anabolic steroids is less likely to be resolved without treatment. 

Anabolic steroids and gynaecomastia 

Gynaecomastia is mainly caused by the effect of androgens (“male hormones”, including testosterone) and oestrogens (“female hormones”) on breast tissue. Oestrogen causes breast tissue to grow and androgen restrains it. Male breast tissue has receptors for both oestrogens and androgens. Men can develop gynaecomastia mainly due to androgen deficiency or excess oestrogen production. It can also occur when both androgen and oestrogen levels are within their normal reference value, but their ratio is skewed. Sometimes a lack or inactivity of androgen receptors in the breast tissue can cause gynaecomastia even when androgen levels are normal. [1]

Anabolic steroids have both androgenic and anabolic effects. Androgens are aromatised to oestrogen, meaning that the body coverts testosterone into oestrogen. However, not all anabolic steroids become aromatised to oestrogen. Especially strong androgens, such as testosterone, are more easily aromatised. When large amounts of aromatisable anabolic steroids are used, oestrogen levels also increase. [1, 6]  

Gynaecomastia can also occur after stopping the use of anabolic steroids due to lower testosterone levels in the body. This is called anabolic steroid-induced hypogonadism. The use of human chorionic gonadotropin (hCG) is common among anabolic steroid users. Its use may cause gynaecomastia or aggravate it. [7, 8]

Symptoms and treatment 

Often, you can feel gynaecomastia as symmetrical, firm tissue under the nipple. Gynaecomastia often occurs in both breasts, but may also be present in only one. Pain is often a sign of rapidly developing gynaecomastia. Gynaecomastia does not usually involve discharge from the nipples. [1, 9]

Although gynaecomastia is often benign, it is important to have it checked. Sometimes, gynaecomastia may be caused by a more serious condition, such as a tumour in the testicles or adrenal glands. It is also important to distinguish whether it is adipose tissue, breast tissue or breast cancer. This allows the right treatment to be started. [1, 9]

A doctor should consider the possibility of anabolic steroid-induced gynaecomastia in athletic men with small testicles, low sperm count, elevated haematocrit levels and low levels of sex hormone binding globulin (SHGB). [1]

If you suffer from anabolic steroid-induced gynaecomastia, it is vital that you stop using anabolic steroids. Medication is most effective in the early stages of gynaecomastia, and it is unwise to delay the start of drug treatment. At a later stage, some connective tissue will already have become fibrous and will no longer be very responsive to drug treatment. Once the use of anabolic steroids has been discontinued and medication has been started, the gynaecomastia often starts to heal within a few weeks. [1, 7, 8, 9]

Medical treatment 

Medicine used to treat gynaecomastia includes drugs that reduce oestrogen production and function. These are aromatase inhibitors and antiestrogens. They are common drugs used to treat gynaecomastia, although there is little research data or official recommendations to support their use. However, practice has shown them to be effective in the treatment of gynaecomastia. [1, 6, 8]

Tamoxifen is the most typically used antiestrogen (more specifically, the selective oestrogen receptor modulator SERM). Tamoxifen blocks oestrogen activity in breast tissue and is often used as a first-line treatment for gynaecomastia. Clomifene is also used to treat gynaecomastia, but with less success. Aromatase inhibitors are not as popular or effective as tamoxifen. [1, 6, 8, 10]

If gynaecomastia is caused by low testosterone levels, testosterone can be used as a treatment. Keep in mind, however, that this also involves the risk of gynaecomastia, because testosterone aromatises to oestrogen. The risk is particularly high for men who are overweight. [1, 9]

Surgical treatment 

If the gynaecomastia has been present for a long time (more than a year), does not respond to medication and is very disruptive for the person suffering from it, surgery may be recommended. [1, 7, 9] Small amounts of breast tissue may remain in the breast despite the surgical intervention. If the use of anabolic steroids is continued, the risk of the recurrence of gynaecomastia is high. Anabolic steroid users may have a higher risk of post-operative complications due to structural differences when compared to other patients with gynaecomastia. The patient can expect to recover from the surgery back to full training fitness within 4 to 6 weeks. [11, 12]

Joni Askola, Master of Health Science, Dopinglinkki


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[2] Mustajoki P. Rintojen kasvu miehellä (gynekomastia). 2022. Lääkärikirja Duodecim

[3] Ferguson A, Cervinski M. Endocrine disorders of the reproductive system: Gynecomastia. Kirjassa: Winter W, Holmquist B, Sokoll L, Bertholf R. Handbook of diagnostic endocrinology. 3. painos. 2020. s. 173-174

[4] Bonnecaze A, O’Connor T, Aloi J. Characteristics and attitudes of men using anabolic androgenic steroids (AAS): A survey of 2385 Men. Am J Men Health. 2020:1–12

[5] Smit D, de Ronde W. Outpatient clinic for users of anabolic androgenic steroids: an overview. Neth J Med. 2018;76(4):167

[6] Bond P, Smit D, de Ronde W. Anabolic-androgenic steroids: How do they work and what are the risks? Front Endocrinol. 2022; 13:1059473

[7] Kanakis G, Nordkap L, Bang A, Calogero, Bártfai G, Corona G, Forti G, Toppari J, Goulis D, Jørgense N. EAA clinical practice guidelines-gynecomastia evaluation and management. Andrology. 2019;7(6):778-793

[8] Rahnema C, Lipshultz L, Crosnoe L, Kovac J, Kim E. Anabolic steroid-induced hypogonadism: diagnosis and treatment. Fertility Sterility. 2014;101(5):1271-1279

[9] Ranta V. Gynekomastian syy ei aina selviä. Suomen lääkärilehti. 2014;69(43):2795–2799

[10] Dickson G. Gynecomastia. Am Fam Physician. 2012;85(7):716-722

[11] Babigian A, Silverman R. Management of gynecomastia due to use of anabolic steroids in bodybuilders. Plast Reconstr Surg. 2001;107(1):240-2

[12] Vojvodic M, Xu F, Cai R, Roy M, Fielding J. Anabolic-androgenic steroid use among gynecomastia patients. Ann Plast Surg. 2019;83(3):25