SOD1 and endometriosis: Vitamin C levels in the FF were significantly lower in the endometriosis group compared to the control group (12.7 ± 5.9 vs. 9.7 ± 6.9 mg/mL, p = 0.003), and there was a trend toward reduced plasma SOD activity (0.9 ± 1.4 vs. 0.5 ± 0.7 U/mL, p = 0.059).