Gynaecomastia in adolescents in athletes: causes and the link with exercise load and pharmacology

Enlargement of the mammary glands in adolescent boys is a very common phenomenon that most often resolves on its own. Yet in the sporting environment it takes on an added dimension: adolescents are ashamed of their appearance, and some of them encounter “sports pharmacology” even before puberty is complete. The editorial team explains where pubertal gynaecomastia comes from, which factors intensify it and why hormonal drugs at this age are dangerous.

What gynaecomastia is and how it differs from fat

Gynaecomastia is a benign enlargement of the glandular tissue of the mammary gland in men. On palpation, a firm, elastic, sometimes painful mass is felt under the nipple, located symmetrically relative to the nipple. It can be one-sided or two-sided.

It should be distinguished from pseudogynaecomastia (lipomastia) — an accumulation of adipose tissue in the chest area without enlargement of the gland. It is characteristic of overweight adolescents and is usually soft to the touch, without a firm disc under the nipple. A doctor’s examination and, if needed, an ultrasound help to tell these conditions apart.

Pubertal gynaecomastia is very common. According to reviews, its signs are present at some point of puberty in a third to more than half of boys. It usually appears in mid-puberty, at about 13–14 years, and in most cases disappears on its own over a period of a few months to two years.

Only a small share of cases persists after the completion of puberty. It is precisely these persistent cases, as well as atypical ones (very large, rapidly progressing, one-sided firm masses), that require closer attention.

Why pubertal gynaecomastia occurs

The key mechanism is a temporary imbalance between oestrogens, which stimulate the growth of breast tissue, and androgens, which restrain it. At the start of puberty the oestradiol level may rise relatively faster than the testosterone level, or the breast tissue may be especially sensitive to oestrogens.

Part of the testosterone in the body is converted into oestradiol by the aromatase enzyme, especially in adipose tissue. That is why in overweight adolescents aromatisation is higher and gynaecomastia occurs more often, frequently combined with pseudogynaecomastia.

When puberty is complete and the testosterone level stabilises, the balance is restored, and the glandular tissue usually regresses. However, if the enlargement has existed for a long time, the glandular tissue can be replaced by fibrous tissue, which no longer disappears on its own.

Rare cases have also been described in which gynaecomastia in children was linked to the topical use of products with lavender and tea tree oil (Henley et al., 2007): in laboratory studies these oils showed weak oestrogenic and antiandrogenic activity, and after the use of the products stopped, the enlargement regressed.

Sports pharmacology: anabolic steroids, prohormones, “test boosters”

The use of anabolic steroids by adolescents is a documented fact, written about by Kanayama and Pope in reviews on the epidemiology of AAS. The motivation is often linked not to competition but to a desire to change appearance quickly. Gynaecomastia is one of the best-known side effects of steroids.

The mechanism is twofold. First, testosterone and a number of other steroids aromatise into oestradiol, and at supraphysiological doses there is significantly more oestrogen. Second, external hormones suppress the body’s own testosterone production through the hypothalamic-pituitary axis, and after withdrawal a period arises when the body’s own testosterone is low while the oestrogenic action relatively prevails.

In adolescents this effect is layered onto incomplete puberty, and the consequences can be more serious than in adults: besides gynaecomastia, premature closure of the bone growth plates (with a limitation of final height), impaired testicular function, acne and mood changes are described. Drug-induced gynaecomastia often no longer regresses completely.

A particular danger is posed by “prohormones” and supplements of unknown composition sold as “test boosters” or “natural anabolics”. Analyses of such products have repeatedly found undeclared steroids in them. Anabolic agents are banned by WADA at all times, and for young athletes a positive doping test also means disqualification.

• Aromatisation of exogenous androgens into oestradiol.
• Suppression of the body’s own testosterone and a “crash” after withdrawal.
• Progestogenic activity of certain steroids.
• Undeclared hormones in supplements of dubious quality.

Other causes: drugs, diseases, lifestyle

A number of drugs can cause gynaecomastia: spironolactone, ketoconazole, cimetidine, some antipsychotics, drugs for the treatment of HIV, antiandrogens. The reviews by Braunstein (2007) and Narula and Carlson (2014) contain detailed lists. If an adolescent is receiving such drugs, the question is discussed with a doctor rather than the drug being stopped on one’s own.

Endocrine causes are rare but important: hypogonadism (in particular Klinefelter syndrome), hyperthyroidism, testicular tumours producing oestrogens or chorionic gonadotropin, adrenal tumours, chronic liver and kidney diseases. That is why an atypical picture requires examination.

Habits also matter. Excess weight enhances aromatisation. The link of gynaecomastia with alcohol and cannabis use is discussed in the literature, but the data are ambiguous. Quite rarely, gynaecomastia occurs after refeeding following prolonged fasting.

In the sporting context it is worth remembering local factors too: friction, chest injuries and haematomas are sometimes mistaken for gynaecomastia, and vice versa.

Training and the psychological aspect

Strength training itself neither causes nor cures gynaecomastia. Development of the chest muscles can visually change the contour, and a reduction in fat removes the pseudogynaecomastic component, but the glandular tissue does not disappear from exercise.

Sport also has a positive effect: maintaining a healthy weight reduces aromatisation, and participation in team sports supports self-esteem. At the same time, changing rooms, swimwear and training photos heighten the shame that leads adolescents to hide the problem or look for “quick fixes”.

It is precisely here that the risk arises that an adolescent will start taking “anti-oestrogens”, steroids or dubious supplements on their own after reading forums. Such actions can disrupt sexual development and cause consequences far more serious than gynaecomastia itself.

Coaches and parents should know that pubertal gynaecomastia is a common and usually temporary condition, and create an atmosphere in which an adolescent can calmly talk about it with a doctor. We write about diagnosis and prevention in detail in a separate material.

Editorial conclusions

Gynaecomastia in adolescence is a frequent and mostly temporary phenomenon linked to the hormonal changes of puberty.

Excess weight, certain drugs, rare endocrine diseases and, especially, anabolic steroids and prohormones increase the likelihood and persistence of gynaecomastia.

For an adolescent athlete the greatest danger is not gynaecomastia itself but attempts to “solve” it or to “speed up” muscle development with hormonal drugs, which can disrupt sexual development and growth.

We also recommend reading our materials on the prevention and diagnosis of gynaecomastia in adolescents, on the risks of anabolic steroids for young athletes and on safe sports nutrition for adolescents.

References

1. Braunstein GD. Gynecomastia. N Engl J Med. 2007;357(12):1229–1237.
2. Narula HS, Carlson HE. Gynaecomastia—pathophysiology, diagnosis and treatment. Nat Rev Endocrinol. 2014;10(11):684–698.
3. Kanakis GA, Nordkap L, Bang AK, et al. EAA clinical practice guidelines—gynecomastia evaluation and management. Andrology. 2019;7(6):778–793.
4. Henley DV, Lipson N, Korach KS, Bloch CA. Prepubertal gynecomastia linked to lavender and tea tree oils. N Engl J Med. 2007;356(5):479–485.
5. Kanayama G, Pope HG Jr. History and epidemiology of anabolic androgens in athletes and non-athletes. Mol Cell Endocrinol. 2018;464:4–13.
6. Pope HG Jr, Wood RI, Rogol A, et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014;35(3):341–375.
7. World Anti-Doping Agency. Prohibited List. Montreal: WADA; чинна редакція.