The ingredient, explained
Ascorbic Acid
The ascorbic acid form of vitamin C has been studied topically for photoaged skin, pigmentation and experimental ultraviolet damage.
Ingredient guide
What it is and what it does
Ascorbic acid
About this ingredient: EU CosIng ingredient registry (via Open Beauty Facts taxonomy) ↗
- Antioxidant
- Limits oxidation, including deterioration of formulation ingredients. This label alone does not show a clinical antioxidant effect in skin.
- Tyrosinase inhibitor / brightening
- Research category for changes in pigmentation or uneven skin tone. The label does not establish that a finished product changes pigmentation.
- Buffering
- Helps resist changes in a formula's pH.
- Masking
- Reduces or conceals the formula's underlying odour or taste.
- Skin conditioning
- A broad cosmetic role for maintaining skin condition. It does not identify a particular clinical benefit.
Function definitions: European Commission ingredient function definitions (SCCNFP/0299/00, pages 16 to 20) ↗ · Original niacinamide study: Pigmentation and hyperpigmented spots ↗
Registry functions describe possible formulation roles, not results for a finished product. A dictionary entry is not an approval or a safety assessment.
A closer look
What the research shows
Selected research
A six-month vehicle-controlled study of 5% ascorbic acid cream reported improvements in photoaged neck and arm skin. A 16-woman melasma trial found better subjective improvement with 4% hydroquinone than 5% ascorbic acid, while colour measurements did not differ significantly. A separate ultraviolet experiment tested ascorbic acid with tocopherol and ferulic acid.
What this does not tell us
The melasma trial included daily sunscreen. The ultraviolet study tested a combination and cannot isolate vitamin C. These results are specific to ascorbic acid and the studied vehicles, not all vitamin C derivatives or finished serums.
Sources for this summary. PubMed 12823436 ↗PubMed 15304189 ↗PubMed 18603326 ↗
Research review checked Sep 30, 2026
Selected primary sources were reviewed for the existing research brief on 30 September 2026, with exact ingredient, route and combination limitations recorded. This was a bounded editorial review, not a systematic search.
Ingredient research is not proof that a product containing this ingredient works.
Read the 3 selected studies
Human topical research
Topical ascorbic acid on photoaged skin. Clinical, topographical and ultrastructural evaluation: double-blind study vs. placebo. ↗
Experimental dermatology · 2003
Human topical research · n=16
A double-blind randomized trial of 5% ascorbic acid vs. 4% hydroquinone in melasma. ↗
International journal of dermatology · 2004
Human research on a combination
A topical antioxidant solution containing vitamins C and E stabilized by ferulic acid provides protection for human skin against damage caused by ultraviolet irradiation. ↗
Journal of the American Academy of Dermatology · 2008
Follow the formula
Products containing this ingredient
From the Serenfold edit. Linked by the ingredient list, without an efficacy ranking.
Names and identifiers
Registry identity
Ascorbic acid
- INCI name on ingredient lists
- ASCORBIC ACID
- CAS registry number
- 50-81-7, 62624-30-0
- EC number
- 200-066-2 / 263-644-3
Other recorded names (1)
- acidum ascoribicum
Sources for this ingredient record
- EU CosIng ingredient registry (via Open Beauty Facts taxonomy) ↗ · ODbL 1.0 (Open Beauty Facts database) · Recorded Aug 8, 2026