Hydrating products are designed to add water into the skin, while moisturizing products help keep that hydration in the skin by preventing trans-epidermal water loss (TEWL), which is the process by which water evaporates from the skin. Hydrating ingredients attract water to the outermost layer of the skin, while moisturizing ingredients lubricate the skin to prevent water from escaping. Some products, like most moisturizers, usually contain a combination of moisturizing and hydrating skin-care ingredients, but that’s not always a given. Hydrating serums, for instance, often just contain hydrating ingredients and require other products to seal the water they provide into the skin.
The right combination of hydrating and moisturizing ingredients for your skin will depend on your skin type and the concerns you’re trying to address. Skin that tends to be dry will likely need both hydrating and moisturizing ingredients, whereas with oily skin, more occlusive moisturizing ingredients may cause breakouts. Some ingredients, such as humectants, can both hydrate and moisturize the skin. Examples of hydrating ingredients include honey, gelatin, urea, sorbitol, panthenol, glycerin, hyaluronic acid, and alpha hydroxy acids. Examples of moisturizing ingredients include occlusives, such as petrolatum, beeswax, mineral oil, and lanolin, and emollients, which strengthen the skin barrier function and promote an improvement.
Hydration is the physical process of absorbing water from food or drink, and roughly 20-30 percent of our hydration comes from food, whereas 70-80 percent comes from drinks. Our body uses water for many different functions, including bodily temperature regulation, joint lubrication, digestion and waste removal, cell functioning, and moisturizing our bodily tissues including our muscles and sensory organs. When dehydration sets in, a series of internal changes occur, and it can lead to a range of symptoms, including headaches, fatigue, and dizziness.
In addition to drinking enough water, maintaining a balance of electrolytes such as sodium is also important because of the different ways we lose fluid. Some beverages, such as skim milk, have been found to rank higher than plain water for their ability to keep us hydrated for a long time. However, the right balance of hydration and electrolytes will depend on individual needs and preferences.
