Retinol is the chemical name for vitamin A. Scientists first remarked its skin-friendly benefits back in the 70's, when they discovered that dry, irritated skin could be caused by a lack of vitamin A. They then decided to use vitamin A-derived molecules - retinol - to deal with various skin problems. Retinoic acid was first used to treat acne, before researchers realised that it also had beneficial effects on skin's appearance and elasticity. In the 90's it took the anti-ageing skincare word by storm, thanks to its ability to minimise the four classic signs of ageing: dry skin, loss of elasticity, thinning skin and the appearance of wrinkles. But it wasn't suited to sensitive skin and caused flare-ups including irritations, rashes and inflammation. Retinol was suddenly put on the back burner in favour of hyaluronic acid, antioxidants and peptides, and more.