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 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.
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.