Vitamin C: The Complete Guide
Collagen cofactor, colds, liposomal marketing, and why 1g is enough for almost everyone
Vitamin C is an essential cofactor for collagen and a water-soluble antioxidant. Deficiency is rare on mixed diets; megadoses do not buy lifespan. This guide covers food vs ascorbic acid, the cold literature, and when a cheap NOW capsule is rational next to collagen powder.
Health Disclaimer
This content is for general informational and educational purposes only. It is not medical advice, diagnosis, or treatment. Consult a qualified healthcare provider before starting any supplement, peptide, or health protocol. Read our full health disclaimer.
Frequency
Daily with food if supplementing
Duration
Ongoing or seasonal
Level
Beginner
Key Takeaways
- 1Eat produce first; supplement when travel or winter diet is sad
- 2200–500mg covers most people; 1g is a convenient capsule, not a better outcome
- 3Colds: prevention evidence is weak; duration may shorten slightly in some trials
- 4Liposomal C is optional if cheap ascorbic acid wrecks your gut
Who this is for
- ·Anyone stacking collagen without the cofactor
- ·Readers tempted by $60 liposomal bottles
- ·Oxalate-stone patients who need a clinician, not a gram at bedtime
What It Actually Does
Strong EvidenceHumans lost the gene to make ascorbic acid. We need it for collagen cross-links, carnitine, and several neurotransmitters. Scurvy is the deficiency disease — not ‘suboptimal glow.’
Peppers, kiwi, citrus, and broccoli cover the RDA easily. Capsules are for gaps, not identity.
Colds and Megadoses
Moderate EvidenceCochrane-style reviews find little prevention benefit in the general public; some shortening of duration, especially in people under extreme physical stress.
Pauling-era grams-per-hour protocols are not a longevity stack. Unused C is excreted. High doses raise diarrhea and oxalate-stone risk.
With Collagen
Moderate EvidenceIf you buy collagen peptides, a small C dose with the shake is more rational than a fourth flavor of powder. NOW C-1000 can be split.
As an Amazon Associate, Reo Tuku Iho Limited earns from qualifying purchases through Amazon links on this site. Full disclosure
For educational purposes only. Not medical advice. Read our health disclaimer.
Sources
Key references cited in this guide. Links open the original publication or abstract.
- Vitamin C for preventing and treating the common coldCochrane Database Syst Rev, 2013
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Read guideLast updated: 2026-09-21 · For informational purposes only. Not medical advice. Consult a healthcare provider before starting any new health protocol. Health disclaimer.