Anabolic/androgenic steroids can inhibit the growth- supporting effects of estrogen on mammary tissues, and may cause a visible reduction in breast size (breast atrophy). Androgen use in females has specifically been shown to cause a reduction in glandular tissue size, and to promote an increase in fibrous connective tissue. These physiological changes are similar to those noted after menopause, when female sex steroids are very low.
Reductions in breast size produced by AAS may be very persistent after the discontinuance of drug intake, as there can be substantial local tissue remodeling under excess androgen influence. Women are warned of the potential for substantial physical changes in the breasts with anabolic/androgenic steroid abuse.
Wlliam Llewellyn (2011) - Anabolics