AbstractPurposeVitamin A has multiple functions in the human body, being involved in growth, epithelial differentiation, vision, immune function and reproduction. While normal spermatogenesis is influenced by several factors, it requires vitamin A. Systemic isotretinoin is a vitamin A derivative that is used in the treatment of many dermatological diseases, especially acne vulgaris (AV). There is limited research on the changes in semen parameters after systemic isotretinoin therapy in humans. Our study investigates the presence of varicoceles in patients undergoing systemic isotretinoin therapy for AV and examines whether there were any changes in the semen parameters before and after treatment.MethodsIncluded in the study were 46 men patients who were scheduled for systemic isotretinoin therapy for AV. Before treatment, the patients underwent a physical examination and ultrasonography for varicoceles assessment. The patients underwent spermiogram before treatment and after 6 months of treatment. The spermiogram assessments included semen volume, sperm concentration, total sperm count, progressive motility, viability and sperm morphology.ResultsAfter treatment, there was an increase in semen volume, sperm concentration, total sperm count, progressive motility and vitality from the pre-treatment values, but a deterioration in the sperm morphology (p< .05). Comparing patients with and without varicoceles revealed more changes in semen parameters after treatment in those with varicoceles. There was a statistically significant difference in sperm concentration (p< .001).ConclusionsSystemic isotretinoin therapy negatively affects sperm morphology, but has positive effect on other semen parameters, and these changes in semen parameters occur more frequently in patients with varicoceles.KEY MESSAGESAcne vulgaris is a very common disease and systemic isotretinoin is used as the most effective agent in its treatment.Systemic isotretinoin positively affects semen parameters except sperm morphology.Changes in semen parameters are more common in patients with varicocele.