Role of antioxidants in treatment of male infertility: an overview of the literature

Seminal oxidative stress in the male reproductive tract is known to result in peroxidative damage of the sperm plasma membrane and loss of its DNA integrity. Normally, a balance exists between concentrations of reactive oxygen species and antioxidant scavenging systems. One of the rational strategies to counteract the oxidative stress is to increase the scavenging capacity of seminal plasma. Numerous studies have evaluated the efficacy of antioxidants in male infertility. In this review, the results of different studies conducted have been analysed, and the evidence available to date is provided. It was found that although many clinical trials have demonstrated the beneficial effects of antioxidants in selected cases of male infertility, some studies failed to demonstrate the same benefit. The majority of the studies suffer from a lack of placebo-controlled, double-blind design, making it difficult to reach a definite conclusion. In addition, investigators have used different antioxidants in different combinations and dosages for varying durations. Pregnancy, the most relevant outcome parameter of fertility, was reported in only a few studies. Most studies failed to examine the effect of antioxidants on a specific group of infertile patients with high oxidative stress. Multicentre, double-blind studies with statistically accepted sample size are still needed to provide conclusive evidence on the benefit of antioxidants as a treatment modality for patients with male infertility.