Pump
Vitamin C
Vitamin C is an essential antioxidant vitamin with no evidence for acute pre-workout performance benefit.
How it counts: Not part of the score
We show it on the label and count it as disclosed, but it never affects Dose, any sub-score or the grade. The basis below explains why.
- Clinical dose
- No established clinical dose
- Safety ceiling
- —
- Evidence
- weak
- Category
- Pump
Evidence summary
Research confidence: low
No pre-workout reference dose. Vitamin C is an essential vitamin (adult RDA 75-90 mg, upper limit 2,000 mg a day); no study shows it improves a workout when taken beforehand. Trials giving about 1,000 mg a day, alone or with vitamin E, for 8-11 weeks found it can blunt some training adaptations (Gomez-Cabrera 2008; Paulsen 2014), at roughly five times the 195 mg PureWay-C blend in these products, so that concern is unlikely at label doses. PureWay-C's faster-absorption claim rests on one small single-dose study with no exercise outcome.
Research sources
- Vitamin C: Fact Sheet for Health Professionals (NIH Office of Dietary Supplements)(opens in new window)
- Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance (Gomez-Cabrera et al., Am J Clin Nutr 2008)(opens in new window)
14 men, 8 weeks of endurance training, double-blind; the 5 given 1 g/day vitamin C had significantly smaller gains in endurance capacity (P=0.014) and blunted mitochondrial-biogenesis markers
- Vitamin C and E supplementation hampers cellular adaptation to endurance training in humans: a double-blind, randomised, controlled trial (Paulsen et al., J Physiol 2014)(opens in new window)
54 young adults, 11 weeks, 1000 mg vitamin C + 235 mg vitamin E daily: VO2max and shuttle-run gains matched placebo, but mitochondrial markers (COX4, PGC-1alpha) rose only on placebo
- Vitamin C and E supplementation alters protein signalling after a strength training session, but not muscle growth during 10 weeks of training (Paulsen et al., J Physiol 2014)(opens in new window)
32 strength-trained adults, 10 weeks, 1000 mg C + 235 mg E daily: muscle growth unaffected, some strength gains (biceps curl) hampered, acute training signalling blunted
- Effect of strength training combined with antioxidant supplementation on muscular performance (Dutra et al., Appl Physiol Nutr Metab 2018)(opens in new window)
42 women, 10 weeks of strength training, 1 g/day vitamin C + 400 IU vitamin E: muscle thickness gains matched placebo; peak torque and total work gains were attenuated
- Vitamin C-lipid metabolites: uptake and retention and effect on plasma C-reactive protein and oxidized LDL levels in healthy volunteers (Pancorbo et al., Med Sci Monit 2008)(opens in new window)
The only human study of PureWay-C found: single 1000 mg dose gave higher serum vitamin C than ascorbic acid, calcium ascorbate and Ester-C. No performance outcome; abstract does not state funding or sample size (unverified)