Age-related changes: As men age, the secretion of testosterone in their bodies typically decreases, leading to a reduction in penis size Long-term masturbation: If a man frequently masturbates, it can easily lead to the corpora cavernosa of the penis being in a state of congestion, which in turn can cause the penis to become smaller and smaller. It is recommended that men reduce the frequency of masturbation to avoid sexual dysfunction Weight gain: If a man overeats for a long time, it usually leads to weight gain, resulting in abdominal obesity, which can make the penis appear shorter and smaller The main point is that insufficient kidney qi leads to a lack of adequate nutrition for the penis, resulting in its being short and small