Hyaluronic acid is a hyaluronic acid that is widely distributed in all parts of the body and can be used in medical aesthetics. It is by far the most powerful moisturizing substance, with wrinkle-reducing, filling as well as hydrating effects. Many cosmetics contain hyaluronic acid, and some manufacturers even produce hyaluronic acid that can be applied directly to the epidermis. However, hyaluronic acid can only be applied to the epidermis and cannot penetrate deeply into the skin, making it difficult to achieve a good moisturizing and filling effect. By the same token, because of the superficial action of hyaluronic acid, it generally does not have side effects, and it will not have a big impact even if the candidate rubs hyaluronic acid on his face for a long time. However, it should be noted that hyaluronic acid contains sodium ions in its composition, which can gradually deepen the color of the skin with long-term use. Therefore, when using cosmetics and skin care products containing hyaluronic acid ingredients, beauty seekers must choose regular manufacturers and use products approved for listing by the Drug Administration, and must not be greedy for cheap hyaluronic acid products. Once skin abnormalities appear, immediately stop using hyaluronic acid and seek medical treatment if necessary.