Oral hyaluronic acid generally has no side effects. Hyaluronic acid is a mucopolysaccharide structure, which has the function of moisturizing and hydrating. Oral hyaluronic acid is water-soluble, mainly glycoprotein is absorbed and turned into carbon dioxide and water, in fact, its half-life is very short, metabolism is very fast, 1-2 days later can be metabolized, eaten into the stomach with the gastrointestinal tract digestion, can be excreted to the body through the feces, so oral hyaluronic acid has no side effects. The role of oral hyaluronic acid that can really reach the surface of the skin is minimal, in fact, it does not have much effect on the skin, so oral hyaluronic acid cannot achieve the role of moisturizing and hydrating. You can inject hyaluronic acid to achieve the effect of moisturizing and hydrating, but you must go to a regular hospital and find a professional and qualified dermatologist for treatment.