Ingredients and actives

Retinol

Also written as retinoid, vitamin A serum.

A vitamin A derivative that degrades on contact with light and air. Formulators stabilise it, but stabilisation buys time rather than immunity.

What it needs from a bottle

Put it in something opaque and airless. Clear glass on a retinol serum is a formulation decision disguised as a design decision, and the customer pays for it in potency by month four. Amber glass is the minimum, an airless pump is better because it never lets a headspace of air sit on the product.

Formats that suit it

• Amber glass droppers
• Airless pump bottles