Hi, Thanks for posting in HCM. I understand your concern. Masturbation is a normal and healthy physiological phenomenon. It does not cause any ill effects on health, fertility or sexual performance. However, it should not be done in excess. It appears from your description that you are doing it more than normal and it would be advisable to reduce the frequency. Tamoxifen is an estrogen receptor antagonist, which works by blocking the receptor so that estrogen can’t work its usual effects within the body. Hence, what doctor has advised is right and kindly take the medication as advised. Some of the side effects experienced with the use of this drug include: Hot flashes, nausea, leg cramps, muscle aches, hair thinning, headache, numbness or tingling sensation of skin and loss of libido. Kindly review with your doctor and do the follow-up as necessary. Hope the information provided would be helpful. All the best.