**2. The evolution of moisturisers: from fundamental ingredients to tailored products**

The evolution of topical moisturisers is basically equivalent to an odyssey from fundamental ingredients (e.g., emollients, humectants, occludents, excipients) [6, 35, 42] (Section 2.1) to specialty molecules (e.g., ceramides, Panthenol, nicotinamide) [6, 35] (Section 2.2) and functionally distinct actives (e.g., corticosteroids, tar-based ingredients, keratolytics) [43, 44] (Section 2.3). Therefore, understanding the interplay and synergism amongst different ingredients as well as being familiar with their ever expanding biophysical effects is essential to get a cosmetically acceptable and/or therapeutically stable tailored product (Section 3) with the desired impact on both healthy and diseased skin [6, 35].
