A vitamin C serum formulated for reactive skin. L-Ascorbic Acid is paired with olive leaf extract, pure vitamin E as tocopherol, and vitamin A as retinol, with bioflavonoids and zinc sulfate alongside. iS Clinical does not publish the vitamin C percentage for this formula. It is a thin, quick-drying fluid, lighter than most antioxidant serums, and it suits skin that finds a standard vitamin C too much.

For sensitive, redness-prone, blemish-prone or mature skin. This is the one we choose when a client reacts to everything else. Mornings, three to four drops on dry skin, before moisturizer and under SPF. There is retinol in it, so keep any separate retinoid to alternate nights rather than doubling up. Six to eight weeks.