Is it possible to treat gynecomastia without surgery?

Yes: But only by avoidance of causative factors if present.

Not really.: Certain behaviors, drugs increase the risk of gynecomastia, so avoiding these helps prevent gynecomastia formation. Once the breasts are enlarged, surgery is usually the best option. The major exception to this is for teen aged boys who have recently developed gynecomastia, as pubescent gynecomastia may resolve on its own in a year or two. A full hitory and physical exam is needed before treatment.

Weight loss: There are some individuals who have used off label indications if tamoxifen but this is not withou my risk and only advised if closely followed and prescribed by an endocrinologist with appropriate testing and monitoring. Surgery is usually the best and most permanent option that is the standard of care.