Oxidative stress is when levels of reactive oxygen species (ROS) reach harmful levels in the body. It happens when the body’s own antioxidant defenses are overwhelmed because of disease, old age, an unhealthy lifestyle or environmental pollutants (14
). ROS are constantly being produced in the body, but their levels are kept in check in healthy people. High levels of ROS may promote tissue injury and inflammation, increasing the risk of chronic disease (17
). There is also some evidence that oxidative stress and excessively high levels of ROS may lead to infertility in men (18
). Adequate intake of antioxidants
, such as vitamin C, may help counteract some of these harmful effects. There is also some evidence that vitamin C supplements may improve semen quality. A study in infertile men showed that taking 1,000-mg vitamin C supplements twice a day for up to two months increased sperm motility by 92% and sperm count by more than 100%. It also reduced the proportion of deformed sperm cells by 55% (20
). Another observational study in Indian industrial workers suggested that taking 1,000 mg of vitamin C five times a week for three months may protect against DNA damage caused by ROS in sperm cells. Vitamin C supplements also significantly improved sperm count and motility, while reducing the numbers of deformed sperm cells (21
). Taken together, these findings suggest that vitamin C may help improve fertility in infertile men suffering from oxidative stress. However, controlled studies are needed before any definite claims can be made.
Summary: Oxidative stress may lead to infertility in men. Some evidence indicates that taking antioxidant supplements, such as vitamin C, may improve fertility.