Across 3 of 4 studies, statistically significant beneficial effects on reducing oxidative stress were reported, yielding a mixed predominant effect size (ranging from small to large). Higher-quality evidence in clinical populations (coronary artery disease, older women with sarcopenia) showed moderate-to-large effects. The median study duration was 84 days (12 weeks), suggesting effects typically require several weeks, though most studies did not specify form or dose.
Caveats: The evidence base is limited to 4 studies, making conclusions preliminary. Effects were context-dependent, with benefits concentrated in clinical populations and a neutral finding in athletic populations. Effect sizes varied widely, and specific forms or doses of vitamin C were generally unreported, limiting the precision of recommendations.
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)