Ingredients and actives

Retinal

Also written as retinaldehyde.

A step closer to retinoic acid than retinol, so it works at lower percentages. It is also less stable and it is yellow, which shows through clear packaging.

What it needs from a bottle

Same rules as retinol, applied harder. The colour is worth designing around: a frosted or amber bottle hides the yellow tint that customers otherwise read as a product that has turned.

Formats that suit it

• Amber glass droppers
• Airless pump bottles