Can Oral Minoxidil Cause Gynecomastia?
No, oral minoxidil does not cause gynecomastia. Gynecomastia is not a recognized side effect of minoxidil therapy at any dose, whether used for hypertension or alopecia treatment.
Evidence Base
Established Side Effects of Oral Minoxidil
The documented adverse effects of oral minoxidil are well-characterized and do not include gynecomastia:
- Hypertrichosis (unwanted body hair growth) is the most common cosmetic side effect, occurring in 15-17% of patients at low doses (≤2.5 mg daily) used for hair loss 1
- Cardiovascular effects including reflex tachycardia, fluid retention, hypotension, and lightheadedness are the primary systemic concerns, particularly at antihypertensive doses (5-100 mg daily) 1, 2
- Pericardial effusion is a rare idiosyncratic reaction that can occur with minoxidil use 2
- Edema and weight gain from sodium and water retention are common, especially without concurrent diuretic therapy 3, 2
Recognized Causes of Gynecomastia
Gynecomastia results from an imbalance between estrogen and androgen action, typically due to increased estrogen production, decreased androgen production, or both 4. The condition occurs as a side effect of many medications and recreational drugs, in the setting of chronic liver disease, hormonal changes, and with aging 5.
Minoxidil is not listed among the medications that cause gynecomastia in comprehensive reviews of this condition 6, 4.
Clinical Implications
When Evaluating Male Patients on Oral Minoxidil with Breast Symptoms
If a male patient taking oral minoxidil develops gynecomastia, you should:
- Search for alternative causes including other medications, hormonal disorders, chronic liver disease, or testicular/adrenal tumors 6, 4
- Do not attribute the gynecomastia to minoxidil, as this is not a recognized adverse effect of the drug
- Consider that 30% of males will experience gynecomastia at some point in their lives from physiologic or other pathologic causes 4
Common Pitfall to Avoid
Do not discontinue minoxidil therapy based on the assumption it is causing gynecomastia, as this will deprive the patient of effective treatment for their underlying condition (hypertension or alopecia) without addressing the actual cause of breast tissue enlargement.