Hello dear, The size of penis is genetically determined and it does not increase after a certain limit. But one thing should be known that the size of penis does not determine the potency of an individual. So, do not get influenced by any over the counter medication which claim to increase the size of penis or improve performance...it may be harmful. Though medications like Cialis & Viagra increase blood flow to penis & maintains erection, it can be improved by having a diet rich in fruits, vegetables, fish, nuts & honey. Avoid stress...practice meditation..this helps in improving concentration & builds up the confidence level. Avoid smoking & alcohol. You can also do oil massage of the penis...it increases blood flow & maintains the erection. Wishing you a Healthy Life. Take care.