These compounds may be synthetic or made from organic materials, such as lecithin from soya beans and sunflower seeds. Lecithin refers to any group of fatty substances, including phospholipids that keep moisture within the skin's upper layer. Aside from preventing escape of precious moisture from the skin, humectants also pull in moisture from the air to supply the skin cells of much needed fluids.
A favorite among dermatologists is hyaluronic acid, which has regenerative properties. This is why most anti-aging skin care products include this as ingredient. This compound is naturally produced by the human body to protect cartilages from deterioration because of friction between bones in the joints. It can hold on to moisture a thousand times more than its weight. Apart from hyaluronic acid, skin care products also contain sodium PCA, glycerin, and urea.
Lipids are a special type of humectants because they form a barrier on top of skin to hold on to the moisture gathered from the air and from exposure to water. These substances are also found in cellular membranes, which need them to prevent moisture inside the cells from escaping. Often described as ceramides or stearic acid in lotions and creams, these lipids or fats are crucial elements to keeping skin moisturized for a longer period.
While humectants are responsible for pulling in moisture from the air or from the person's surroundings, occlusives are tasked to stop the droplets of water from escaping. Occlusives are normally found in thick creams and ointments. They help seal in the moisture and promote cellular recovery from cuts and burns. They also prevent cracking and flaking of your topmost skin layer during winter.
Common examples of occlusives include petrolatum and lanolin. However, people with very sensitive skin should avoid these substances. Instead, they should look for dimethicone and shea butter in the list of ingredients in their skin care products.