Vitamin C serum is oil- and water-based liquid that contains high concentrated amounts of L ascorbic acid, chemically active form of vitamin C and has pH3.5. It comes in 10%, 15% and 20% concentrations.

Mechanism of action of vitamin C with reference to dermatology

To be effective as an anti -aging product, a serum should contain 15% - 20% of L ascorbic acid should be used. The efficacy is proportional to the concentration, but only up to 20%.

Side effects of Vitamin C serums

These include itching, redness, peeling for a few days and rarely mild chemical burns in sensitive skin types. To reduce side effects, start weaker concentration (5 - 10%).