Penile shrinkage can occur for various reasons. Usually, changes to penis size are smaller than an inch, however, and may be closer to 1/2 an inch or less. The typical causes of loss of length in your penis include aging, obesity, prostate surgery, and a curving of the penis, known as Peyronie’s disease.
If you begin to develop curvature of your penis with pain and swelling, it may be a sign of Peyronie’s disease. See a urologist for this. This doctor specializes in problems of the urinary tract. Maintaining erectile function is important because erections fill the penis with oxygen-rich blood, which could prevent shortening.