The ingredients in mayo contain sphingolipids (ceramides) which help heal and repair the skin. They act like glue to keep the foundation of your skin strong. Over time, as these ceramides decrease with age, the cells of your skin are less able to hold their form — and that’s what makes your skin thinner and weaker. The reason why it’s important to keep your ceramide levels high — through foods that you eat, nutritional supplements that you take and skin care that you use — is that they help to keep your skin structure together. The simple DIY skincare in the book supply a great dose of ceramides to help your skin glow tightly.