Generally speaking, it takes one month to notice a visible difference in penis size. In most cases, the girth of the penis expands and becomes visible in comparison to the length. Without using the vacuum pump and taking nitric oxide supplements as prescribed by your doctor, length might not significantly increase. But it is important to note that P-shots simply rejuvenate and regenerate aging erectile tissue, restoring it to a younger state. As a result, erections become stronger and better.