01
What is it?
In cosmetics, “vitamin C” does not identify one raw material: it may refer to L-ascorbic acid or derivatives such as ascorbyl glucoside or sodium ascorbyl phosphate. Each form differs in stability, solubility, penetration and tolerance. Pure ascorbic acid is usually formulated at a lower pH and is particularly sensitive to air, light and heat; derivatives aim to improve some of these features, but their evidence and behaviour are not identical.
02
Its role in a formula
Its antioxidant role helps complement the skin's defences against oxidative stress and is used in routines seeking radiance and a more even-looking tone. Some forms are also studied in relation to collagen, but results depend on a stable formula that delivers the active appropriately. It does not replace sunscreen: the two have different, complementary roles.
03
Compatibility and tolerance
It may be formulated with vitamin E and ferulic acid and can also share a routine with niacinamide, hyaluronic acid, peptides or retinoids. There is no universal prohibition between these ingredients; tolerance is usually the practical limit. If two acidic or intensive formulas cause stinging or dryness, alternate times or days rather than forcing every layer into one routine.
04
How do I use it?
Apply after cleansing and before moisturiser, following the formula's dosage. Many people use it in the morning alongside sun protection, although it can also be used at night. Start on alternate days if your skin is sensitive and increase only while comfort is maintained. Close the packaging properly, store it as directed and avoid unnecessary exposure to light or heat.