How long does pubertal gynecomastia last?

Usually < 1yr: Pubertal gynecomastia may effect the majority of males as the begin their pubertal transition. Most are minimal and last 6m to a year, but occasional longer episodes do occur (1-3yr) it is important to separate the true process from fatty breast enlargement that produces a false gynecomastia in overweight kids. Spongy glandular tissue directly under the nipple is absent in the false case.

1-2 years: Difficult to pinpoint an “average” duration of adolescent gynecomastia; for many young men this process continues for 1 to 2 years before resolving spontaneously. For many however the process continues into adulthood. Gynecomastia can be seen in all age groups.