Vitamin C has a specific, non-substitutable role in collagen production. It's required as a cofactor for the enzymes that stabilize collagen into its functional triple-helix form. Without adequate vitamin C, the body cannot produce functional collagen — which is why scurvy (severe vitamin C deficiency) historically presented as a collagen-disorder syndrome with bleeding gums, joint problems, and impaired wound healing.

The mechanism

Two enzymes — prolyl hydroxylase and lysyl hydroxylase — modify the proline and lysine amino acids in newly-formed collagen, allowing the three protein strands to wind together into the stable triple helix. Both enzymes require vitamin C as a cofactor.

Without enough vitamin C, the modifications don't happen properly. The collagen that's produced is structurally weaker, less stable, and less functional.

The dose conversation

The U.S. RDA for vitamin C is 75-90mg/day — set to prevent deficiency, not to optimize collagen synthesis. The dose required for optimal collagen synthesis is somewhat higher; trial evidence supports 100-500mg/day for skin and connective tissue endpoints.

Vitamin C is water-soluble and excreted readily, so excess intake is typically harmless. Doses above 1g/day occasionally cause GI upset.

RenuYou's role

RenuYou includes 60mg vitamin C per daily serving — at the lower end of the supportive range. This works as a supplemental top-up alongside dietary vitamin C from fruits and vegetables. For optimal collagen synthesis, total daily intake of 100-200mg from food and supplements combined is the target.

Food sources

Vitamin C is widely available in:

  • Citrus fruits (oranges, lemons, grapefruits)
  • Bell peppers (red peppers especially high)
  • Strawberries
  • Kiwi fruit
  • Broccoli, brussels sprouts
  • Tomatoes

One large red pepper has roughly 200mg vitamin C — more than the RDA in a single serving.

The smoking caveat

Smokers have substantially higher vitamin C requirements (recommended intake 35mg/day higher than non-smokers) due to oxidative damage. Smokers also have measurably worse collagen quality and skin aging — partly due to direct effects, partly due to the vitamin C burden.

The honest summary

Vitamin C is a non-substitutable cofactor for collagen synthesis. Adequacy is essential; modest supplementation supports the optimal end of the range. RenuYou includes it because the collagen peptides delivered need vitamin C to be properly used — the building blocks alone aren't enough.