What Causes Gynecomastia in Men? Steroids, Supplements, Obesity, and Hormones ExplainedAustin Gynecomastia Center

For decades, gynecomastia has been most commonly attributed to persistent pubertal breast development—hormonal changes during adolescence that simply never resolved. While this explanation remains valid, it no longer accounts for the majority of cases seen in modern clinical practice.

Today’s male patients live in a very different hormonal environment.

Based on experience from thousands of gynecomastia surgeries across all age groups, the most common drivers we now see are medication-, supplement-, and lifestyle-related hormonal disruptions, often compounded by obesity. These factors are far more prevalent today than in prior generations and better explain the patterns of gynecomastia presenting well beyond adolescence.

Anabolic steroids, testosterone replacement therapy, SARMs, peptides, finasteride, and other hormone-modulating medications are widely used—not only by athletes, but by men pursuing fitness, longevity, and anti-aging goals. Many over-the-counter supplements also contain compounds with estrogenic or pro-hormonal effects that are poorly regulated and often under-recognized.

At the same time, obesity plays a significant role. Excess adipose tissue increases aromatase activity, converting testosterone into estrogen and creating a chronic estrogen-dominant state. Over years or decades, this sustained hormonal exposure leads to the development of dense, fibrotic breast tissue that does not regress on its own.

This evolution matters. It explains why gynecomastia is now seen across a wider age spectrum, why medical therapies often fail, and why complete surgical excision remains the most reliable solution for lasting correction.

Understanding the modern causes of gynecomastia is essential—not only for effective treatment, but for honest patient education in an era where hormones, supplements, and obesity are part of everyday life.