vitamin C
A salt compound of hyaluronic acid, a substance with the same skin structure. A powerful moisturizer and skin conditioner that can absorb 1000 times its own weight in water. It is one of the best moisturizers at present, but you need to pay attention to whether the concentration is sufficient to achieve the effect.
ref.
International Journal of Toxicology, volume 24, supplement 2, 2005, pages 51-111
Experimental Dermatology, September 2005, pages 684-691, and June 2003, pages 237-244
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