Dear Dr G,

I am a man in my mid-40s and am relatively healthy. Due to inactivity during the MCO, I started putting on weight.

When I went for a check-up, the doctor discovered I was suffering from high blood pressure, glucose intolerance and dyslipidemia.

I also developed depression as I lost my job and was prescribed a whole barrage of pills.

However, six months after starting on the pills, some things have literally gone out of shape.

The waistline has expanded further but more distressingly, I have developed man boobs.

I understand that polypharmacy (the use of several different drugs) can have side effects and would like to have some clarification.

How common is drug-induced gynecomastia (development of breast tissue or known colloquially as moobs)? How does it induce breast enlargement in men? Can it be reversed? And should I stop taking the pills?


Heavy-chested Henry

Gynecomastia is the most common benign disorder of the male breast tissue, affecting one in every three men. Gynecomastia commonly occurs between 50 and 69, with an estimated prevalence up to 70% in men. Although the condition is largely benign, gynecomastia can cause significant psychological distress and unease.

It is commonly caused by a hormonal imbalance of estrogen and androgen. The prevalence of gynecomastia in men may have increased in recent years, yet the epidemiology of the disorder is not fully understood. The increased use of medicine, anabolic steroids, exposure to chemicals that mimic estrogen in plastic and cosmetic products, organochlorine pesticides have been suggested as possible factors driving this increase.

Drugs are estimated to cause about 10-25% of all cases of gynecomastia. Over the course of several decades, multiple medications have been implicated in the development of gynecomastia. The medicine are predominantly antiandrogens, steroids, heart medicines, opioids, antiviral, antifungal and psychiatric drugs.

Antiandrogens are used to treat metastatic prostate cancers. Medicine such as bicalutamide and flutamide are known to cause gynecomastia by antagonist action to testosterone and dihydrotestosterone on mammary glands. Other related drugs such as 5-alpha-reductase inhibitors used for hair-loss and prostate enlargement can also reduce the active form of testosterone, therefore enhancing the estrogen/androgen ratio. Gynecomastia usually appears during the first year of antiandrogens use for 40-70% of patients on long-term treatment.

Estrogen plays a key role in the development of breasts in both men and women. When the estrogenic effect is restricted less by androgen, excessive breast enlargement is observed. Common heart medicines that can cause are digoxin and calcium channel blockers while anabolic steroids and heart rhythm regulators such as digoxin raise the amount of estrogen in the body. Additionally, antihypertensive drugs such as calcium channel blockers and spironolactone can enhance estrogenic effects.

Certain antifungals such as ketoconazole and antivirals for treating HIV such as efavirenz are known for their estrogen-like properties, causing excessive breast tissue growth.

Also, drugs commonly used in psychiatry such as diazepam, tricyclic antidepressants and ADHD medications that contain amphetamines can tip the balance of androgen and estrogen in men. Such hormonal imbalance often results in gynecomastia within months of starting treatment.

Then there are illicit and recreational substances that are notorious for causing breast enlargement in men. Excessive alcohol and anabolic steroids used for bodybuilding can impair liver function resulting in cirrhosis, which in turn causes excessive anti-androgenic effects in men. Marijuana, heroin and methadone also have similar impacts on the liver, resulting in gynecomastia.

Many would consider using natural products as “immune” from all the toxic influences of chemicals. On the contrary, even natural products will have certain impacts on the hormonal balances in life. Plant oils such as tea tree or lavenders used in shampoos, soaps and lotions have all been implicated with weak estrogenic activities. This in turn is associated with gynecomastia in men.

Gynecomastia is generally a benign condition that reflects an imbalance of sex hormones. Such breast enlargement in older men is often a natural progression of aging, with or without the influences of external sources.

Thomas Edison once said: “Doctors of the future will give no medicine but will instruct his patients in the care of the human frame, diet and the cause and prevention of disease”. Dr G has a similar view and hopes that an apple a day and a healthier lifestyle can keep the doctors, the medicines and gynecomastia away.

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