Breast tissue growth reflects a shift in the oestrogen–androgen balance. Early tissue can regress; long-standing tissue often does not.
Mechanism
Aromatisation of androgens to oestradiol, and suppression of natural testosterone after stopping, can both tip the balance toward breast tissue growth.
Some medications and liver disease contribute independently.
Time course
Early proliferative tissue may regress, while longer-standing fibrotic tissue is less likely to respond to medication.
A firm, one-sided or rapidly growing lump should be assessed rather than assumed to be drug-related.
Assessment
Clinical examination, hormone tests and sometimes imaging guide management. Self-treating with grey-market ancillaries masks the cause and adds side-effect risk.
In short
- Gynaecomastia reflects hormonal imbalance.
- Timely assessment improves options.
- Unusual lumps always need examination.
Cited studies
These studies provide context for the article; findings may not apply to non-medical use or products sold online.
Narula HS, Carlson HE. (2014). Gynaecomastia — pathophysiology, diagnosis and treatment. Nature Reviews Endocrinology.
Read the study ↗Braunstein GD. (2007). Clinical practice. Gynecomastia. New England Journal of Medicine.
Read the study ↗
Unfamiliar terminology is defined in our glossary. How we research and grade evidence is set out in our editorial standards, and errors can be reported through corrections.
This article is educational. It is not medical advice, a dosing recommendation, or an endorsement of use. Speak with a qualified medical practitioner about your circumstances.