Unlike most other ceramides, this is a tricky one to recognize by name, but Hydroxypalmitoyl Sphinganine is a type of ceramide. The TL;DR version of ceramides is that along with cholesterol and fatty acids, the lipid trio (in a 50%, 25% and 15% ratio) is in the outermost layer of the skin helping to maintain a healthy skin barrier. This means keeping nasty things out, and important things such as water in. We have a more detailed description of ceramides here.
So as a ceramide, Hydroxypalmitoyl Sphinganine is a nice skin-identical ingredient that supports a healthy skin barrier. More specifically, a promising in-vitro study on reconstructed human skin shows that applying our molecule helps the skin to make some more ceramides (types 1,2 and 3). Interestingly, the extra ceramide production does not happen in the usual pathway, but the skin seems to process and transform Hydroxypalmitoyl Sphinganine into these other ceramides.
Clinical, aka made on real people studies, have confirmed that products with Hydroxypalmitoyl Sphinganine improve skin hydration, reduce trans epidermal water loss (the amount of water that evaporates out of the skin), and increase the ceramide content of the skin in people with atopic dermatitis or who are being treated with topical tretinoin. A real goodie in our book.
Show me some proof
- Meckfessel, Matthew H., and Staci Brandt. "The structure, function, and importance of ceramides in skin and their use as therapeutic agents in skin-care products." Journal of the American Academy of Dermatology 71.1 (2014): 177-184.