Stable form of vitamin C that is considered an analogue of L-ascorbic acid. Unlike pure vitamin C (ascorbic acid), tetrahexyldecyl ascorbate is lipid (fat) soluble.
Some researchers believe this form of vitamin C has a greater affinity for skin because its fatty acid component helps aid penetration. It pairs well with other forms of vitamin C and retinol for enhanced effectiveness.
References for this information:
Clinics in Plastic Surgery, July 2016, page 601
Journal of the American Academy of Dermatology, Supplement, May 2014, pages AB26
Dermatologic Surgery, March 2002, pages 231-236