Low semen may be caused by physiological or pathological reasons. Low semen may indicate a decrease in sperm count, but it is not absolute. Semen is composed of seminal plasma and spermatozoa, with seminal plasma accounting for more than 90% of the volume of semen. Spermatozoa are produced by the testes, mature in the epididymis, and are discharged through the vas deferens. Seminal plasma is mainly a mixture of fluids secreted by accessory glands such as the prostate, seminal vesicle and urethral bulb glands, and also includes a small amount of testicular fluid and epididymal fluid. In general, normal human semen is between 1.5 and 2 ml. A decrease in any of the components will result in a decrease in semen. Physiological causes mainly include frequent sexual intercourse or masturbation leading to frequent ejaculation, short intervals between ejaculations, and the components of semen not being replenished in time, resulting in low semen. If the amount of semen is low for a long time, you should be alert to whether it is accompanied by diseases, such as urethritis, prostatitis and seminal vesiculitis. Excessive psychological stress or mental tension can also lead to a decrease in semen. It is possible that a decrease in semen can lead to infertility, so once found it is still necessary to seek medical attention and check semen routine. In summary, low semen includes physiological and pathological factors. Once found, it is recommended to seek medical attention, check semen routine and treat it in time.