For more mature skin, or for those who have been using OTC retinol for a while, Dr Ross Perry, owner of skin clinics chain Cosmedics, rates Medik8's Crystal Retinal 6 (£59), used as a night cream. And just like Medik8's Intelligent Retinol serums, these come in increasing percentages.
"This range contains retinal, a new formulation on the classic retinol that gives up to 11 times the effect. It also has hyaluronic acid, glycerin, and vitamin E to help hydrate the skin at every level," Dr Perry explains. So, how does retinal differ from retinol? Well, as we mentioned before, retinol converts in the skin to retinaldehyde and then to retinoic acid. But retinal only has to convert to retinoic acid, so it's much faster acting (and better suited to existing users with skin that's adapted to retinol use).