The brief: build a wardrobe of four serums that cover the four canonical jobs — antioxidant defence, cell-turnover, exfoliation, and tone-and-barrier — and have each one earn its slot independently. We trial-stocked twenty-three serums from $9 to $480. Each panellist held one of the four jobs for a fortnight, then rotated, so every serum was scored by every panellist across at least one cycle.
We score four things only: tolerance at week one, visible change at week four, layering behaviour (does it pill under SPF, does it disrupt the next product), and the price-per-bottle judgement. The panel spans Fitzpatrick II through V; two members are on prescription tretinoin and tested the C E Ferulic and niacinamide only; one has melasma and gave us the read on the vitamin C lift.
Editor-in-Chief Elizabeth Agresta led the read-out. Four serums cleared the bar across all four scoring dimensions. The other nineteen didn’t. The four below are the wardrobe the editors actually run at home.