Chitosan is a product of N-deacetylation of chitin. Chitin, chitosan, and cellulose have similar chemical structures. Cellulose is a hydroxyl group at the C2 position, and chitin and chitosan are replaced by an acetyl and amino group at the C2 position, respectively. Chitin and chitosan have many unique properties such as biodegradability, cell affinity, and biological effects, especially chitosan containing free amino groups, which is the only alkaline polysaccharide in natural polysaccharides. The amino group in the molecular structure of chitosan has stronger reactivity than the acetylamino group in the chitosan molecule, which makes the polysaccharide have excellent biological functions and can undergo chemical modification reactions. Therefore, chitosan is considered a functional biomaterial with greater potential for application than cellulose. There is a large amount of chitin in the shells of marine arthropods such as shrimp and crabs, insects, fungi and algae cell membranes, mollusks' shells and bones, and the cell walls of higher plants. Chitin is widely distributed in nature, with reserves ranking only behind cellulose, making it the second largest natural polymer. Chitosan is currently a component used in advanced cosmetics and skincare products. When used in medical cosmetic procedures such as pulsed light, radio frequency, dot matrix, and fruit acid, it acts as a natural antibiotic to resist sensitivity and anti-inflammatory reactions, quickly repair basal heat damage, heal wounds, and repair the epidermal barrier. In addition, chitosan skincare products also have the function of metabolizing heavy metals! The most impressive thing is that chitosan is a component in the world that can adsorb heavy metals, skin toxins, and hormones! Effectively metabolize heavy metals, hormones, and haze that remain in the skin layer due to long-term makeup. The efficacy of these forks has earned them a mythical status in skin beauty repair!