What drug increases breast tissue? A guide to medication-induced gynecomastia

October 12, 2025 •

3 min read

According to research, drug-induced gynecomastia accounts for about 20-25% of all adult cases of benign male breast enlargement. The condition, where a drug increases breast tissue, is often caused by a hormonal imbalance that can result from various prescription or recreational substances.

Quick Summary

Certain medications can cause an increase in breast tissue by disrupting the balance between testosterone and estrogen, increasing prolactin levels, or other hormonal pathways. Several types of drugs, including anti-androgens, antipsychotics, and cardiovascular medications, are implicated in this side effect. Management often involves addressing the underlying cause or discontinuing the problematic drug.

Key Points

Hormone Imbalance Is Key: Gynecomastia occurs when drugs alter the body's natural balance of estrogen and androgens, with increased estrogenic effect or decreased androgenic activity.
Risperidone is a Notorious Offender: The antipsychotic risperidone (Risperdal) is particularly known for causing gynecomastia, especially in adolescents, due to elevated prolactin levels.
Spironolactone Is a Common Cause: This diuretic is a frequent cause of gynecomastia due to its anti-androgenic effects, though less common alternatives like eplerenone exist.
Anti-Androgens Have a High Risk: Medications used for prostate conditions like finasteride and bicalutamide often cause gynecomastia by blocking testosterone.
Discontinuation is the First Step: In most cases of drug-induced gynecomastia, stopping the offending medication leads to a reversal of the condition.
Surgery is a Last Resort: For long-term or persistent cases, medical management may be followed by surgical removal of the breast tissue if it does not resolve.

Gynecomastia is the benign enlargement of male breast glandular tissue, which can be caused by natural hormonal shifts during infancy, puberty, or aging. However, a significant portion of cases are triggered by pharmacological agents. This occurs when a medication disrupts the delicate balance of hormones in the body, primarily by increasing estrogen's relative effect or suppressing androgen's activity. For individuals taking long-term medication, understanding the potential for this side effect is crucial.

The Hormonal Mechanisms of Medication-Induced Breast Growth

Breast tissue growth is largely driven by estrogen and inhibited by an imbalance between androgens (like testosterone) and estrogen. Medications can influence this hormonal landscape through several key mechanisms, including estrogenic activity, anti-androgenic effects, hyperprolactinemia (elevated prolactin levels), increased aromatase activity (converting androgens to estrogens), and interference with hormone production.

Medications Commonly Associated with Gynecomastia

Several classes of drugs are known to cause gynecomastia as a side effect. The risk depends on dosage, duration of use, and individual susceptibility.

Anti-Androgen Agents

These drugs, used for conditions like prostate cancer or benign prostatic hyperplasia, block or reduce male hormone activity. Examples include spironolactone, known for its dose-dependent risk, and flutamide and bicalutamide, used for prostate cancer. Finasteride, used for BPH and hair loss, also inhibits the conversion of testosterone to a more potent androgen.

Antipsychotic Medications

Certain antipsychotics, particularly second-generation agents, can cause hyperprolactinemia.

Risperidone (Risperdal): Frequently linked to gynecomastia, especially in younger males, due to elevated prolactin levels.
Haloperidol (Haldol): Can also increase prolactin levels.

Cardiovascular and Gastrointestinal Drugs

Cimetidine (Tagamet): An older H2-receptor antagonist with anti-androgenic properties.
Digoxin: Can bind to estrogen receptors, causing breast enlargement.
Spironolactone: Mentioned previously for its anti-androgen effects, also used in cardiovascular treatment.

Other Drug Classes and Substances

Anabolic steroids, estrogen therapy (used in hormone replacement and gender-affirming therapy), marijuana, heroin, and alcohol have all been associated with gynecomastia. Anabolic steroids can lead to gynecomastia as excess testosterone is converted to estrogen.

Comparison of Drug-Induced Gynecomastia


Drug Class	Primary Mechanism	Risk of Gynecomastia	Onset of Symptoms	Reversibility	Notes
Anti-androgens	Blocks testosterone activity	High, especially at high doses	Varies; often months after starting	Usually reversible after discontinuation	Examples: Spironolactone, Bicalutamide
Antipsychotics	Increases prolactin levels	Variable, higher with Risperidone	Can occur within weeks to months	Mixed; depends on duration and severity	Examples: Risperidone, Haloperidol
Cardiovascular Drugs	Mixed (anti-androgen, estrogen-like)	Low to moderate	Can be months to years	Often reversible upon discontinuation	Examples: Spironolactone, Cimetidine, Digoxin
Anabolic Steroids	Increased estrogen production	High, especially with aromatizable forms	Can be rapid with high doses	Reversible after stopping; often persists	Conversion of testosterone to estrogen
Estrogen Therapy	Direct breast tissue stimulation	Expected	Gradual, starting within months	Reversible, but long-term effects may linger	Intentional effect in gender-affirming therapy

Management and Treatment of Drug-Induced Gynecomastia

Managing medication-induced gynecomastia starts with reviewing the patient's medications. If a drug is the likely cause, options include:

Discontinuation or Substitution: Stopping the problematic medication is often effective. For example, eplerenone may be used instead of spironolactone. This should only be done under medical supervision.
Observation: Mild or temporary cases, such as during puberty, may be monitored.
Medical Therapy: Medications like tamoxifen or aromatase inhibitors may be used for painful or severe cases.
Surgical Intervention: Surgery may be necessary for long-standing or significant cases, particularly when glandular tissue is involved.

Conclusion

Identifying what drug increases breast tissue is crucial for managing gynecomastia, a condition that can cause significant psychological distress. Numerous medications, including anti-androgens and antipsychotics, are implicated. Effective management often involves identifying and potentially stopping the causative drug. Open communication with your doctor about all medications is essential for prevention and management. More information is available from resources like the Mayo Clinic.

Frequently Asked Questions

Medications most likely to cause gynecomastia include anti-androgens (e.g., spironolactone, bicalutamide), antipsychotics (e.g., risperidone), and some cardiovascular drugs (e.g., digoxin).

Yes, several illicit and recreational drugs, such as marijuana, heroin, and anabolic steroids, have been linked to gynecomastia due to their effects on hormone balance.

Gynecomastia caused by medication is often reversible, especially if the drug is stopped shortly after the onset of symptoms. However, if the condition persists for a long time, the glandular tissue can become fibrous and may not regress completely without surgery.

The time for resolution varies depending on the medication and individual. Some cases may resolve within weeks to months, while others can take longer or require additional treatment.

The primary cause is an imbalance between estrogen and testosterone, either due to an increase in estrogenic effects or a decrease in androgenic effects.

Yes, if a specific medication is identified as the cause, a healthcare provider may switch you to an alternative with a lower risk of gynecomastia. For example, eplerenone can sometimes replace spironolactone.

While gynecomastia is a benign condition, it is important to distinguish it from male breast cancer. Men with gynecomastia may have increased anxiety about breast cancer, but the condition itself is not typically premalignant.