There isn't a universally agreed-upon list of exactly twelve ceramides. The number and specific types vary depending on the source and context (e.g., synthetic versus naturally occurring ceramides). However, several sources mention a range of ceramides, and some focus on specific subsets.
Key Ceramides Mentioned in Research and Skincare
Many resources highlight certain ceramides frequently found in skincare products or studied in research. These include, but are not limited to:
- Ceramide 1 (EOS): Often mentioned in skincare product lists.
- Ceramide 2 (NS or NG): Another common ceramide in skincare formulations.
- Ceramide 3 (NP): Frequently appears alongside Ceramide 1 and 2.
- Ceramide 6-II (AP): A group of related ceramides, often cited together.
- Ceramide 9 (EOP): Like Ceramide 6-II, this often appears grouped with others.
- Phytosphingosine: A related compound frequently included in ceramide discussions within the context of skin health.
- Sphingosine: Similar to Phytosphingosine, often found alongside other ceramides.
- Ceramide 12 (d18:1/12:0): Specifically mentioned in chemical databases. This nomenclature highlights the specific fatty acid chains involved in this particular ceramide.
Some sources list "Ceramides 1-12," suggesting twelve distinct varieties; however, the precise chemical structures for each aren't uniformly defined across all publications. The provided references contain information on some of these ceramides but don't list a definitive, complete set of twelve. Many ceramides exist, and their nomenclature can be complex.
Synthetic PseudoCeramides
It's important to distinguish between naturally occurring ceramides and synthetic "pseudo-ceramides" used in skincare. One source lists twelve synthetic pseudo-ceramides, including those mentioned above (Ceramide 1, 2, 3, 6-11, and 9, along with Phytosphingosine and Sphingosine).
