The Impact of Cigarette Smoking on Semen Quality and Male Fertility: A Review of Current Evidence

Male infertility represents a major global health concern, with lifestyle-related factors increasingly recognised as contributors to lowering reproductive potential. Cigarette smoking is one of the most significant modifiable risk factors affecting male fertility due to the presence of toxic compounds capable of inducing oxidative stress, DNA damage, and impaired spermatogenesis. This literature review summarises current evidence published in articles regarding the impact of cigarette smoking and alternative nicotine products on semen quality and male fertility. The reviewed studies consistently demonstrated that smoking is associated with reduced semen volume, sperm concentration, total sperm count, and motility, alongside increased sperm DNA fragmentation and epigenetic alterations. Oxidative stress emerged as the central pathogenic mechanism, reinforced by mitochondrial dysfunction, abnormal DNA methylation, reduced antioxidant capacity, and formation of DNA adducts. Conventional semen analysis may underestimate smoking-related fertility impairment, as molecular and epigenetic abnormalities may persist despite apparently normal semen parameters. Smoking cessation was consistently associated with improvements in semen quality, particularly in sperm concentration and total sperm count, with longer abstinence producing greater recovery. Alternative nicotine products, including e-cigarettes, snus, and hookah, were also linked to adverse reproductive effects, although their degree of toxicity may differ from that of conventional cigarettes. Overall, current evidence supports smoking cessation as an important intervention for improving male reproductive health and highlights the need for further research into molecular markers of fertility impairment beyond routine semen analysis.