01.
Apply in the morning
Vitamin C works with SPF to amplify daytime UV protection.
Apply before moisturiser, after cleansing.
What is vitamin C serum?
The topical antioxidant with the best-documented anti-ageing evidence outside retinol. How to use it without wasting it.
Vitamin C in skincare comes in multiple forms. L-ascorbic acid (highest-efficacy, most unstable) is the gold standard. Stabilised esters (magnesium ascorbyl phosphate, sodium ascorbyl phosphate) are gentler and more stable.
Topical vitamin C brightens pigmentation, protects against free radicals, and boosts collagen production.
Stability is the big challenge. Most vitamin C products oxidise within 3 months. An oxidised (yellow-brown) product does nothing.
The method
02.
Stability — the critical factor
Look for packaging that excludes light (opaque, amber, pump).
Store in fridge if you can. Use within 6 months of opening.
Check colour: yellow → fine. Orange-brown → oxidised, discard.
03.
Don't layer with retinol
Morning C + night retinol is the classic pairing.
Using together deactivates both.
Products we reach for
Recommended № 01 · SkinCeuticals
C E Ferulic
The benchmark vitamin C. 15% L-ascorbic acid + vitamin E + ferulic. Stabilised, clinically studied, expensive.
Recommended № 02 · Drunk Elephant
C-Firma Fresh Day Serum
Stabilised vitamin C in a cleaner format than CE Ferulic. Mix-to-activate for freshness.
Recommended № 03 · Medik8
C-Tetra Luxe Vitamin C Serum
Stabilised ester-form vitamin C in a lipid base. Gentler than L-ascorbic, doesn't sting sensitive skin.
Common questions
Can I use this every day?
Depends on your skin and concentration. Start 2-3x/week, build up.
When will I see results?
8-12 weeks for most actives. 4-6 weeks for niacinamide. Retinol: 12-16 weeks.