Our bodies are 70% water. So think of a glass of water and oil, like a salad dressing, with the oil on top of the water–I think this is a great visual to show how oils help the skin retain moisture for longer amounts of time. I have been a big fan of using oils in my beauty routines for a long time, and as I have gotten older, my skin has definitely become more dry. Most water-based moisturizers get absorbed readily into the layers of the epidermis, or they evaporate (like water does) off the skin, but oil and oil-based lotions actually “sit” on top of the skin–just like the oil in a salad dressing. In the colder winter months, when the air is super dry, I apply a regular lotion and then add an oil on top of that. The water from the shower, plus the water-based lotion create a good base, but adding the oil seals that moisture onto the surface of the skin so it actually absorbs and does not evaporate right off my skin. I like to use an oil on my face at night after I apply my night ritual creams, for the same reasons. I like a light-weight oil like grapeseed, and am loving Josie Maran’s Argan Oil. I use Neutrogena Body Oil, which is sesame-based–I like to add it to my bath water. I also stick to pretty strict rules about the standards of oil that I will use: Can I put it IN my body? Yes? Then put it ON your body. Petroleum-based oils are out. Would you dress a salad with “baby oil” or “mineral oil?” I wouldn’t either, so don’t put it on your body. Your body absorb these chemical concoctions, so stick to plant-based, natural oils in the kitchen and in the bathroom. Oils have different weights and thicknesses, and heat thresholds for cooking. Try coconut oil, olive, evening primose, avocado, sesame, grapeseed, borage, castor, rose hip, jojoba, peanut, apricot kernel, almond, shea butter, and wheat germ oil. Make your own blend, or try one at a time. I buy what is on sale. Sometimes the cosmetic aisle has higher prices than the grocery shelf (ah, the price of beauty) so compare and choose the lower price. They are the same product, just marketed differently. A little bit goes a long way, so storing oils in the refrigerator might be good advice. Oils also dissolve oils, so they can be blended as gentle face cleansers. I thought this link had great advice for an oil cleansing method. I use Josie Maran’s Argan Cleansing Oil. Using an oil for cleansing helps the skin heal and retain valuable moisture, so that the body does not over-produce oil, which causes blemishes in the first place.