What vitamin C actually does
Antioxidant protection
Vitamin C neutralises free radicals generated by UV exposure, pollution, and environmental stress. Free radicals damage DNA, break down collagen, and accelerate visible aging. Vitamin C applied before SPF in the morning provides a layered defence that no SPF alone can match.
Collagen synthesis
Vitamin C is essential for collagen synthesis — the skin cannot produce collagen without it. Topical vitamin C upregulates the genes that control collagen production, meaning regular use supports firmer, more resilient skin over months of consistent application.
Brightening and dark spot fading
Vitamin C inhibits the enzyme tyrosinase, which is responsible for melanin (pigment) production. Regular use fades existing dark spots, evens out post-inflammatory hyperpigmentation, and gives a general brightening effect. Results take 4-8 weeks of consistent use to become visible.
The different forms of vitamin C
L-ascorbic acid (LAA) is the most studied and most effective form — but also the most unstable. It oxidises when exposed to air and light (turns orange/brown — at which point it is inactive). Look for opaque or dark packaging and low pH formulations (under 3.5) for best stability.
Vitamin C derivatives (ascorbyl glucoside, sodium ascorbyl phosphate, ascorbyl tetraisopalmitate) are more stable and less irritating, but generally less potent. A good choice for sensitive skin or beginners.
How to use vitamin C correctly
- Apply in the morning — it pairs with SPF for maximum antioxidant protection
- Apply to clean, dry skin before moisturiser
- 3-4 drops for the entire face — start with 2-3 days per week if you have sensitive skin
- Store in a cool, dark place — a bathroom cabinet or drawer is fine, direct sunlight is not
- If your serum turns orange or brown, it has oxidised and is less effective — replace it
Concentration guide: 10% is effective for brightening with lower irritation risk. 15-20% is the clinical sweet spot for antioxidant protection and collagen benefits. Above 20% increases irritation with diminishing additional benefit.
What to pair with vitamin C
Vitamin C works well with SPF (amplifies protection), niacinamide (apply separately — vitamin C morning, niacinamide evening for simplest approach), and ferulic acid (stabilises vitamin C and doubles its antioxidant efficacy — look for C+E+Ferulic formulas).
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