It causes many diseases and can be harmful for long term health. It is unfortunate that most people and doctors say masturbation is harmless and healthy. Either it is a copy-paste-knowledge just because others are saying or it is due to the yet inconclusive medical research on it. Semen and sperms are the vital energy force of the body, so losing it means you start losing mental and physical strengths. Too much masturbation can create erectile dysfunctions, premature ejaculation, thinning of or watery semen etc.