Ingredient

Vitamin C

Also known as: Ascorbic acid, L-ascorbic acid

The pure, water-soluble form of vitamin C. An antioxidant most often used in the morning, under sunscreen.

Typical percentage: 10%
INCI name: Ascorbic Acid
Skin concern: Uneven tone
Skin type: Normal
Combination
Oily
Dry
Benefit: Antioxidant

What it is

Ascorbic acid is vitamin C in its simplest form, with no conversion step needed on the skin. It is an antioxidant, which means it reacts with free radicals from daylight and city air before they react with anything else.

It is also the least stable form. It needs an acidic, low-water formula and a bottle that keeps out light and air. A fresh serum is clear to pale straw; it turns deeper yellow, then amber, as it oxidises.

How we use it

At 10% in a low-pH serum, with 0.5% ferulic acid to slow oxidation. The bottle is opaque and the batch date is printed on the base.

How to use

Morning, on clean dry skin. Two or three drops over the face and neck, then moisturiser and sunscreen.

Pairs well with

Ferulic acid in the same formula, and a broad-spectrum sunscreen on top. Niacinamide can be used in the same routine.

Cautions

A brief tingle is common on first use. If your skin is easily irritated, keep it apart from exfoliating acids and retinal: vitamin C in the morning, the others in the evening. Replace the bottle once the serum has turned amber.

This page is general information, not medical advice. Patch-test any new product.