Antioxidants· in 6 products

Vitamin C

Also listed as L-ascorbic acid, Ascorbic acid, Sodium ascorbyl phosphate and Magnesium ascorbyl phosphate

Moderate evidence 10–20% L-ascorbic acid; derivatives vary

Vitamin C is an antioxidant used in serums to brighten dull skin, even tone and add a layer of defense against UV-generated free radicals under sunscreen. Its most researched form, L-ascorbic acid, is effective but unstable and can sting.

Shop 6 with vitamin c All ingredients

6VcVitamin CAntioxidants

What it does

The short version.

Topical vitamin C neutralizes free radicals created by UV exposure and pollution, is a required cofactor for collagen synthesis, and inhibits tyrosinase, the enzyme that drives melanin production. L-ascorbic acid needs a low pH (around 3.5 or below) to penetrate well and oxidizes on exposure to air, light and heat, turning yellow-orange as it degrades. Derivatives such as sodium ascorbyl phosphate or ascorbyl glucoside are more stable and gentler but have less clinical data.

Moderate evidence

Small randomized trials support improvements in photoaging signs and pigmentation with L-ascorbic acid, and lab studies show added photoprotection when combined with vitamin E and ferulic acid. Evidence for most derivatives is thinner.

In our directory: It’s a key ingredient in 6 products we review, most often serums and lips. Those products are mostly built for fine lines, matte and long-wear. In formulas, it most often shares the label with vitamin e, hyaluronic acid and ferulic acid.

Reach for it for

Brightening Dullness Dark spots Hyperpigmentation Antioxidant Fine lines

Usually a good fit for

Normal skin Combination skin Oily skin Mature skin Dry skin

How to use it

Getting it right.

Apply a few drops in the morning after cleansing and before moisturizer and sunscreen. Store tightly closed and away from light and heat; discard if it turns dark orange or brown.

Layering

Friends & frenemies.

Pairs well with

Vitamin E Ferulic acid Chemical UV filters Zinc oxide Hyaluronic acid Niacinamide

Go slow with

Glycolic acid Salicylic acid Benzoyl peroxide Retinol

Not forbidden — just easier to over-do. Alternate nights or separate morning and evening.

Before you start

Low-pH L-ascorbic acid serums can sting, tingle or cause redness, particularly on sensitive or freshly exfoliated skin. Benzoyl peroxide can oxidize it, so use them at different times of day. Patch test, and complement rather than replace sunscreen.

References

Educational, not medical advice. Ingredient guides summarise published research and expert guidance; formulas and concentrations differ between products.