How Vitamin C Works
How Vitamin C Works — a water-soluble antioxidant, most studied as L-ascorbic acid, that neutralizes free radicals generated by UV exposure and pollution while supporting the skin's natural collagen production. It acts as an essential cofactor for the enzymes that stabilize and cross-link collagen, and it can help interrupt excess melanin formation, contributing to a more even tone over time. Its effectiveness depends heavily on formulation, concentration, and stability.
Key points
- Vitamin C donates electrons to neutralize reactive oxygen species that contribute to visible photoaging.
- It serves as a cofactor for prolyl and lysyl hydroxylase enzymes involved in collagen synthesis.
- It can reduce melanin production by interfering with the tyrosinase pathway, helping fade uneven pigmentation.
- L-ascorbic acid is unstable and oxidizes with light and air, so packaging and low pH influence its performance.
Frequently asked
Is vitamin C better used in the morning or evening?
Vitamin C is often applied in the morning to complement sunscreen against daily free-radical exposure, though it can be used at night and still provides antioxidant benefits.
How can I tell if my vitamin C serum has gone bad?
Oxidized L-ascorbic acid typically turns yellow, orange, or brown, which signals reduced potency even though it is not necessarily harmful.
Related topics
This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.
