A healthy body makes healthy sperm, so the best advice is to maintain a healthy body weight, exercise for 30 minutes daily, sleep 7 hours per night, and eat a healthy diet. Regularly seeing your PCP for general screening of your blood pressure, cholesterol, and blood sugar is important, in addition to closely monitoring and managing any chronic health problems. Avoiding known causes of impaired sperm production such as tobacco, alcohol, and cannabis (marijuana) will help to maintain optimal sperm production. Men should avoid supplements, especially workout-related supplements, protein powders, and any over-the-counter products marketed toward strength, vitality, or sexual function. Many of these workout products contain ingredients that can be harmful to sperm production. Despite all of this general advice, some men will have conditions that cause decreased sperm production which need to be evaluated by a trained reproductive urologist. The most common of these conditions is a varicocele which affects 15% of all men and is the most common cause of an abnormal semen analysis. This is best diagnosed by a physical exam during a consultation for possible male factor infertility.