1. Skin elasticity: Under normal circumstances, the dermis of the skin has elastic fibers and collagen fibers, and the subcutaneous tissue is rich in fat, making the skin elastic and smooth. However, with the increase of age or the aggravation of illness, the skin gradually ages, the dermis shrinks and thins, the elastic fibers and collagen fibers of the skin degenerate, the elasticity decreases, and the hyaluronic acid decreases, which makes the skin lose elasticity, the skin relax and wrinkles appear.
2. Moisturizing skin: The dermis is rich in blood vessels and lymphatic vessels, which is the second largest "reservoir" in the human body after muscles. Keeping skin moist is the premise of keeping skin moist and shiny, which plays an important role in maintaining skin nutrition and preventing skin dryness and wrinkles.
3. Color and texture of skin: The color of skin varies from race to race, including white, yellow, brown, red and black. This is mainly caused by the different quantity and distribution of pigments contained in the skin.
4. Cleanliness and vitality of the skin: The skin should be free of dirt and stains and always kept clean.
5. Normal skin and anti-aging: Normal skin should be insensitive, not greasy and not dry.
In short, beautiful skin should be healthy skin, ruddy and shiny, soft and delicate, compact, elastic and energetic, not rough and greasy, shiny and with few wrinkles.