Retinol is a potent, dermatologist-approved ingredient that speeds up cell turnover to tackle unwanted dark spots, smooth texture, and leave skin looking plump and radiant. Use this Superdrug Optimum Retinol Booster Drops (£13) at night — starting with once or twice a week and working your way up to more depending on how well your skin can tolerate the ingredient — and you'll soon see a difference.