The Essential Guide to Vitamin C

Vitamin C is the most requested and most misunderstood active in skincare. Used well, it brightens, supports collagen, and gives antioxidant protection against daily environmental damage. Used carelessly, it oxidises in the bottle and does very little.

Concentration is not the whole story

Ascorbic acid between ten and twenty percent is effective, but formulation and pH matter more than the number on the label. Derivatives such as magnesium ascorbyl phosphate are gentler and better suited to sensitive or reactive skin.

Storage and pairing

Keep it in an opaque bottle, away from heat and light. If the liquid has turned deep amber, its useful life is over. Vitamin C pairs well with sunscreen in the morning and with vitamin E and ferulic acid in the same formula; it does not need to be layered with every other active you own.

Give it eight to twelve weeks before judging results. Brightening is gradual, and consistency beats concentration every time.