C-Tetra

The classic ester formula

Tetrahexyldecyl ascorbate, the oil-soluble vitamin C, carried in jojoba and light, flash-off silicones with vitamin E as its regenerating partner. The ester slips into skin lipids intact and converts to active vitamin C within, so there is no surface acidity and no sting: daily use from day one.

Why so short a list

A waterless formula needs no preservative system and gives vitamin C nothing to react with, eleven ingredients is the point, not a limitation. This is the original C-Tetra recipe that introduced a generation to ester vitamin C.

What it does over time

Daily antioxidant cover blunts the oxidative load behind visible ageing and dullness, with vitamin C’s well-documented support for brightness, judged in weeks, worn under SPF.

The scent

Grapefruit peel oil, with four declared allergens, noted below.

First-time vitamin C users, sensitive skin that stings with L-ascorbic serums, and anyone building the CSA routine on a sensible budget. All skin types; the silicone-light texture suits normal to combination best.

Worth knowing

Contains grapefruit peel oil with declared limonene, citral, linalool and geraniol, patch test with a citrus or fragrance allergy. When you want more from the same chassis, Advanced adds the acetyl zingerone stabiliser and a hydration bench; Luxe wraps the ester in a facial-oil base.

Mornings on clean, dry skin: 3–4 drops pressed over face and neck, followed by moisturiser and SPF. No ramp-up needed.

Store away from direct sun with the cap tight.

Use alongside

The entry rung of the C-Tetra ladder, C-Tetra to start, Advanced for the fuller build, Luxe for dry skin, and one C serum per routine across the whole shelf. Pairs with an evening retinoid as the morning half of the day-night split, under any moisturiser, always beneath SPF.