Across 4 studies, 3 reported beneficial effects on reducing oxidative stress, with effect sizes ranging from small to large. The most studied populations are clinical groups (coronary artery disease, sarcopenia). The median study duration was 84 days (12 weeks), based on a single trial that used 1000 mg/day of vitamin C (combined with vitamin E).
Caveats: Evidence base is small (only 4 studies) — conclusions should be considered preliminary. Effect sizes varied across studies (small to large). Only one study reported a dose (1000 mg/day) and duration (84 days), limiting dose-response and timing conclusions.
While additional verification of the safety and efficacy of these supplements is still necessary, current evidence suggests that these supplements have potential applications for health promotion and disease prevention among athletes and more diverse populations.
from: Recent Progress in Applicability of Exercise Immunology and Inflammation Research to Sportnine reported on supplemental antioxidants (i.e., L-carnitine and melatonin) ... that were effective at lowering OS (P < 0.05)
the AS group had increased GSH (P < .001, d = 1.52) and GSH/GSSG ratio (P < .001, d = 1.52), and reduced GSSG (P < .001, d = 0.96) and malondialdehyde (P < .001, d = 1.65) compared to the PLA group
reduce oxidative stress (malondialdehyde, glutathione, total antioxidant capacity, superoxide dismutases, protein carbonyls, ascorbate, glutathione peroxidase, and paraoxonase 1)
antioxidant defense modulators (vitamin C, sulforaphane, taheebo)