I discovered the Allies of Skin Triple Hyaluronic Antioxidant Hydration Serum (£74) after running out of a long-time favourite, and was so impressed I kept coming back for more. The formula contains three different types of hyaluronic acid: one with a low molecular weight, one with a high molecular weight, and one botanical form (called cassia angustifolia seed polysaccharide), which means it's ridiculously hydrating. But it doesn't stop there. The rest of the ingredients list reads like a who's-who of dermatologist-favourite skin savers, including peptides, resveratrol, and niacinamides.