OBJECTIVE: Different aspects of the functions of free fatty acid (FFA) in seminal plasma and their implications on male fertility are known. However, the profile of FFA in seminal plasma in asthenozoospermic patients following antioxidant therapy has not been studied. METHODS: In this case-control study, the total antioxidant capacity (TAC) and FFA profile of the seminal plasma were determined in 80 patients (29 normozoospermic volunteers and 51 asthenozoospermic men) who were treated with antioxidants for three months. RESULTS: The TAC level in normozoospermic men was significantly higher than in asthenozoospermic men before and after antioxidant therapy with even lower values after the treatment (p=0.0001). The most abundant identified FFAs in seminal plasma were palmitic acid, vaccenic acid, eicosatrienoic acid, stearic acid, and myristoleic acid. Palmitic acid was lower in asthenozoospermic patients (p=0.0001), and antioxidant treatment restored its level to near-control levels. Compared to normozoospermic controls, the level of eicosatrienoic acid is significantly lower in asthenozoospermia patients before (p=0.01) and after treatment (p=0.0001). Additionally, following oral antioxidant supplementation, the FFA pattern in asthenozoospermic patients changes to the pattern observed in normozoospermic men. However, these changes are not statistically significant. CONCLUSIONS: The TAC level in asthenozoospermic patients after antioxidant treatment did not change to the levels in the control group
it even dropped to a lower level following three months of treatment. Antioxidant treatment can change the level of the FFA compositions of seminal plasma.