Growth of breast gland tissue in men, caused by an imbalance between estrogen and androgen action. With anabolic steroids it results from estrogen produced by aromatisation.
Early gynecomastia presents as tenderness and a soft lump beneath the nipple and can regress if the hormonal cause is removed promptly. Established, firm glandular tissue does not regress and usually requires surgery. Some compounds that raise prolactin can contribute independently of estrogen.
This article is for information and education only. It is not medical advice and does not replace a consultation with a physician. Anabolic-androgenic steroids are prescription medicines in most countries and are controlled substances in many. Check the law where you live.