Human skin has a natural moisturizing system, which is composed by water, natural moisturizing factor (NMF), and lipid. The moisturizing cosmetics that we use now are a stimulation of this system. The main ingredients in moisturizing products are water, moisturizer and oil. Only when we have a better understanding of the ingredients in cosmetics and the structure of our own skin, can we select the cosmetics which are most suitable for our skin. The common moisturizers in cosmetics mainly include the following types.

First, glycerin:
Glycerin is the oldest moisturizer. A decade ago, many people use glycerin mixed with water directly to care their skin in winter. With its safe characteristic and cheap price, glycerin has become the most common moisturizer in cosmetics.

Second, :
Hyaluronic acid is the natural and inherent moisturizing ingredient in human skin. Its capacity of maintaining water is stronger than any other natural or synthetic polymer. Because it is very expensive, so the additive amount of hyaluronic acid in cosmetics is not very great.

Third, :
Collagen is the newest moisturizer developed in recent years. As collagen is similar to the physical structure of stratum corneum, so it can quickly penetrate in the skin, combine with the water in stratum corneum, and form a network structure to maintain the moisture. As the principle of moisturizing of collagen is different from the traditional moisturizer, so some people hold that collagen has opened up a new world of moisturizer. However, as the price of this kind of moisturizer is also very high, so it is not taken as the main component in cosmetics.

Fourth, :
Urea is the product of the natural metabolism of the skin. It has magic effect to soften the skin, so a lot of hand cream contains urea.

Fifth, derivatives:
Chitin derivatives is a kind of natural moisturizing agent extracted from the outer skin of crustacea. The effect of chitin derivatives is similar to hyaluronic acid, so it is a physiologically safe moisturizer. In addition, it is also used as a drug for artificial skin and wound healing.

Sixth, :
Aloe is a kind of vegetative moisturizing agent. As aloe juice contains mucopolysaccharide (MPS), which is similar to hyaluronic acid, so it has good lubricating and moisturizing effect. What's more, it also has an anti-inflammatory effect.

Seventh, seaweed extracts:
Seaweed is the oldest plant in the world. It is rich in amino acids, vitamins and mucopolysaccharides, which has a moisturizing, lubricating and anti-wrinkle effect on the skin.