... A acid Tretinoin INCI Name: Vitamin A acid CAS. NO.: 302-79-4 Chemical name: 3, 7-dimethly-9-(2, ... 6-trimethly-1-cylohexane)-2, 4, 6, 8-pelartetaenoic acid Character: Yellow acicular crystals, ... Howerver, to spread on part of skin has no actual effect. Taking orally vitamin A is benefit ... spread it in thin skin. Proper lower concentration (no more than 0.025%)can avoid such reaction as ...