Alcohol and Cannabis as Causes of Gynecomastia

Alcohol‑Induced Gynecomastia

Alcohol can lead to gynecomastia through two distinct pathophysiologic pathways:

The 2025 clinical guideline (Annals of Internal Medicine) states that chronic cannabis use, especially when initiated during adolescence, may significantly affect hormonal systems, implying a potential risk for gynecomastia. 2
The 2024 ASCO cannabis guideline (Journal of Clinical Oncology) reviews numerous cannabis‑related adverse effects but does not list gynecomastia among documented complications, indicating that the association is less consistent than for other effects. 1

Physical examination should differentiate true gynecomastia (palpable glandular tissue beneath the nipple) from pseudogynecomastia (fat deposition). 5
Laboratory assessment:
- Measure serum estradiol in all patients with gynecomastia before considering hormonal therapy. 5
- Obtain morning total testosterone, luteinizing hormone (LH), and follicle‑stimulating hormone (FSH) to characterize the hormonal profile. 5
- If testosterone is low with low/normal LH, add prolactin measurement to exclude hyperprolactinemia. 5

Substance cessation (reduce or stop alcohol or cannabis use) is the primary intervention for drug‑induced gynecomastia. (Guideline recommendation)
Patients with elevated estradiol should be referred to endocrinology for comprehensive hormonal evaluation. 5
Spontaneous resolution occurs in up to 50 % of cases with non‑cyclical breast symptoms, supporting a watch‑and‑wait approach after substance discontinuation. 5