Penis thinning may be related to congenital urethral malformation, environmental influence, daily habits, trauma and other factors. 1. Congenital urethral malformation: under normal circumstances, the male penile spongiosum will gradually develop and mature after the age of 16. If there is a congenital low level of sex hormones, it will lead to immature development of the spongy body, resulting in a smaller and thinner penis. 2. Environmental influences: If men are in cold weather conditions, the local nerves will be stimulated, which will lead to obvious contraction of the penis, when the temperature returns to normal, the penis will gradually recover. 3. Daily habits: If men have bad habits, such as excessive frequent masturbation, irregular sex life, etc., it will lead to insufficient blood supply to the penis, the erectile function declines, the penis will show thinning. 4. Trauma: If the penis is stimulated by external factors such as burns, extrusion, collision, etc., it will lead to the spongy body development being hindered, causing the penis to become thin. If the thinning of the penis can not be relieved in time, go to the hospital men’s department in time for a detailed examination and symptomatic treatment.