Your skin is the largest organ in the body and the first line of defense against harmful microbes, pollution, and UV rays. In scientific terms, your skin is technically “dry” when its moisture level is less than 10%. That’s when you’re most likely to smother yourself in body lotion. Especially dry, irritated, or inflamed skin is also called Xerosis, which is usually a minor and temporary problem that can be solved with good moisturizing lotions. There are three different layers of the skin: the outer layer (epidermis), middle layer (dermis), and lower layer (hypodermis or fatty layer). Moisture is delivered to the skin via blood vessels, but they only supply moisture to the middle layer of the skin, the dermis. From there, water travels upward and outward through the epidermis before evaporating into the atmosphere. Moisturisers work in one of two main ways: they either trap moisture in your skin to keep it from escaping, or they restore moisture in the outer layer of skin that’s already been lost. With the glut of lotions and creams on the market, it can be easy to get lost in the sea of brand-named jellies. At the most basic level, however, there are three types of moisturisers named Occlusives, Emollients and Humectants. Each works slightly differently, but most products combine all three.