Big effect
In a 12-week trial, adding 335 mg/day vitamin C (with vitamin E) to resistance training slashed a key marker of oxidative damage by a massive effect size of 1.65 — but only in older women already diagnosed with sarcopenia.
This is the strongest signal yet from a small clinical trial that vitamin C can meaningfully reduce oxidative stress in a specific, vulnerable group, but the overall evidence across four studies is only moderate and mixed in effect size, so don't expect this magnitude in a healthy person.
Older women with sarcopenia who took 335 mg/day of vitamin C (plus vitamin E) alongside 12 weeks of resistance training saw a very large drop in malondialdehyde, a marker of oxidative damage to fats, and a similarly large rise in the antioxidant glutathione. The caveat: this was a clinical population with diagnosed muscle wasting, so the results likely don't apply to healthy adults, and the study combined vitamin C with vitamin E, making it impossible to isolate vitamin C's role alone.
Where this fits in the evidence
Pillser has synthesized 4 studies on Vitamin C for Reduced Oxidative Stress — overall evidence strength: Moderate.
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).
The study
- Randomized Controlled Trial (RCT)
- 2025-08-22
- Medicine
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.