INCI: Ascorbic Acid
Water-soluble antioxidant that inhibits tyrosinase and stimulates collagen synthesis. Unstable upon oxidation, requiring careful storage.
Topical application
BLimited evidence. One RCT or several controlled studies with limitations.
Clinical trials confirm efficacy for melasma, photoaging, and photoprotection. Synergy with vitamin E and ferulic acid enhances photoprotective properties. Evidence base is limited by difficulties in standardizing formulation stability.
10–20% (optimal pH 2.5–3.5)
Irritation potential
MediumAllergen risk
LowPregnancy
SafeFor sensitive skin
Concentrations above 15% may cause stinging and redness on sensitive skin. Starting at 10% is recommended.
Suitable for
Use with caution
Works well with
Tocopherol (Vitamin E)Токоферол (витамин E)
Classic pair: vitamin E stabilizes ascorbic acid and enhances photoprotection. Lin 2003 showed 4-fold UVB protection boost when combined.
Ferulic AcidФеруловая кислота
Ferulic acid stabilizes vitamin C and doubles the formula's photoprotective properties. They work as a single antioxidant network.
L-Ascorbic Acid (Vitamin C) is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
L-Ascorbic Acid (Vitamin C) suits: normal, combination, oily. Use with caution in: sensitive, dry.
L-Ascorbic Acid (Vitamin C) has moderate irritation potential. Sensitive skin may show a transient reaction that usually settles with adaptation.
Water-soluble antioxidant that inhibits tyrosinase and stimulates collagen synthesis.
The INCI name is Ascorbic Acid. It may also appear as: Vitamin C, L-Ascorbic Acid, Аскорбиновая кислота.
Published: · updated:
Glycolic AcidГликолевая кислота
Applying vitamin C over AHA boosts bioavailability of both – low pH helps ascorbic acid stability. Best done in the morning.
Does not combine with
Copper Peptides (GHK-Cu)Медные пептиды (GHK-Cu)
Vitamin C reduces copper in GHK-Cu, breaking the peptide. Use at different times: C in morning, copper peptides in evening.
Benzoyl PeroxideБензоилпероксид
BPO oxidizes ascorbic acid, inactivating it. Use at different times of day.
Hydroxypinacolone RetinoateГидроксипинаколон ретиноат
HPR (hydroxypinacolone retinoate) activates at neutral pH and needs a stable environment. Acidic L-AA reduces HPR bioavailability. Better to space them out or use a stable C form.
TretinoinТретиноин
Tretinoin is already irritating, and L-AA at acidic pH adds stinging and dryness. Tretinoin also oxidizes in acidic media. Dermatologists recommend spacing them: C in the morning under SPF, tretinoin at night on dry skin.
RetinolРетинол
Different optimal pH: retinoids need neutral, vitamin C needs acidic. Use at different times: C in morning, retinol at night.
RetinaldehydeРетиналь
Same issue as with retinol: L-AA needs acidic pH (3–3.5), retinal needs neutral. In one layer it oxidizes faster and may amplify stinging. Standard advice – C in the morning, retinal at night.
10–20% (optimal pH 2.5–3.5)