Long-chain, complex fatty alcohol that functions as a water-binding agent and also has preservative qualities. Its name is derived from the term sphingoid, coined in 1884 by chemist J. L. W. Thudichum because the way the molecules of this substance lined up reminded him of the riddle of the Sphinx. Research shows it is effective in regulating damaged or diseased epithelial cells. It seems this ingredient can also be a cell-communicating ingredient, albeit one that is best for compromised skin (Source: Journal of Investigative Dermatology, October 2003, pages 1135–1137).
Phytosphingosine is one of many sphingoid bases (a type of lipid) that occur naturally in the outermost layers of skin. In these layers, it provides some protection against bacteria such as e. coli and staph (Sources: Applied Microbiology and Technology, May 2013, pages 4,301–4,308; and Skin Pharmacology and Physiology, October 2012, ePublication). There is limited evidence proving phytosphigosine impacts acne-causing bacteria, yet it's anti-inflammatory action can have an effect on reducing overall acne symptoms, as at its core, acne is an inflammatory disorder (Source: International Journal of Cosmetic Science, June 2007, pages 181-190).
Note: Products that contain phytosphigosine extract may be a "hidden" source of gluten; however, this form of phytosphingosine is rarely used in cosmetics.