There is no upper limit of normal semen volume, but there is also no way to actually improve semen volume, assuming the body is working properly. The majority of semen volume is fluid that comes from the prostate and seminal vesicles, not actually sperm. Keep in mind that after a vasectomy, semen volume shouldn’t change, because the sperm only contribute about 5% to the volume. A man’s semen volume has more to do with his prostate size as well as his age than anything. Semen volumes decline with aging. All that being said, there are a number of conditions that can arise which can reduce semen volume or create a problem from birth where semen volume is very low. These conditions vary from blockages to issues with ejaculation. Many of these problems that are essentially problems of sperm delivery can result in low or decreased semen volume. If the amount has decreased over time or has lower or slower velocity, or if it comes out in a delayed fashion, such as more than a few seconds after orgasm, there could be a problem that needs medical attention. Treatable blockages can develop from infection or inflammation such as from injury or trauma. Retrograde ejaculation is a very common cause of decreased semen volume, and this can be a symptom of new or worsening diabetes. Other hormonal abnormalities can cause disorders of ejaculation as well. If you are experiencing changes in semen volume or have noticed a decrease, having a semen analysis with retrograde urine assessment, along with a full evaluation with a reproductive urologist is recommended. The treatments vary from lifestyle improvements, to medications to surgery. Changes in semen volume cannot be treated with supplements or any simple home-based therapies. Any purported treatment directed toward semen volume is not coming from evidence-based medicine, so be wary of these false claims.