Ceramide EOP

What it is

Ceramides are the most abundant fat in the stratum corneum, the outermost layer of skin, where they stack with cholesterol and free fatty acids into the lamellar sheets that hold water in and keep irritants out. The letters in a ceramide's INCI name are a specification of its two halves rather than a grade. The first letter gives the fatty acid - N for a normal, non-hydroxy acid, A for an alpha-hydroxy acid, EO for an omega-hydroxy acid that carries a second fatty acid esterified on its far end. The second letter gives the sphingoid base - S for sphingosine, P for phytosphingosine, G for sphinganine. Ceramide EOP takes that EO prefix and a phytosphingosine base, so the molecule carries two tails rather than one. These omega-esterified ceramides are the long, double-tailed lipids that hold the lamellar sheets of the barrier in register, and they are the structurally distinctive corner of the family. It was formerly called Ceramide 1 or Ceramide 1A, both retired in 2014.

How it shows up on a label

What it does well

• Belongs to a class that is essential to barrier formation

  Mice engineered without the enzyme Acsl1 could not make omega-O-esterified ceramides, developed severe skin barrier defects and did not survive gestation. The limits of that finding matter and are worth stating plainly: it concerns the sphingosine-based sibling of this ingredient, and it is a genetic model of a barrier being built from the inside, not a study of anything applied to skin. It establishes that the class is essential; it does not show that applying Ceramide EOP does anything.

  Moderate evidence

• Restores a lipid the skin makes itself

  Ceramide EOP belongs to a subclass of ceramide found naturally in the stratum corneum, so it tops up a lipid the skin already produces. The Panel that assessed these ingredients commented that they would not be readily absorbed through the skin and are expected to remain in the stratum corneum. That is where the effect sits, and it is also the limit of it.

  Moderate evidence

Worth knowing

• Present at low levels

  The highest maximum concentration reported to the CIR survey for products left on the skin was 0.2%, in skin care preparations. That survey covers the ceramides reported in use at the time, this one among their close relatives. Ceramides are among the more expensive cosmetic raw materials, so a product may advertise them and still contain a fraction of a per cent. Where the name falls on the ingredient list is a rough guide to how much is really there.

  Matters most toAnyone paying a premium specifically for ceramide content.

• The evidence is about the class, not the ingredient

  Omega-esterified ceramides are demonstrably necessary to a skin barrier that is being built from within. That is not the same claim as one about a molecule spread on the surface of adult skin for twenty minutes in a mask, and no study here closes that gap. This is a limit in what is known rather than a finding against the ingredient.

  Matters most toAnyone choosing a product on the strength of this ingredient in particular.

Where the EU stands

Sources (3)

Every link goes to the original: a journal, a PubMed record or an EU document.

1. [1]
   Safety Assessment of Ceramides as Used in Cosmetics

   Cosmetic Ingredient Review Expert Panel · 2015

   The Panel concluded that the ceramide ingredients, including this one, are safe in cosmetics in the present practices of use and concentration described in the assessment, and recorded that they are not restricted in any way under the rules governing cosmetic products in the European Union.

2. [2]
   Acsl1 is essential for skin barrier function through the activation of linoleic acid and biosynthesis of omega-O-acylceramide in mice

   Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids · 2022 · doi:10.1016/j.bbalip.2021.159085

   Mice unable to make omega-O-esterified ceramides had severe barrier defects and did not survive gestation, establishing the class as essential to barrier formation - in a genetic model, not a topical one.

3. [3]
   Effects of sphingolipid extracts on the morphological structure and lipid profile in an in vitro model of canine skin

   The Veterinary Journal · 2016 · doi:10.1016/j.tvjl.2016.03.020

   Supplementing a cultured skin model with sphingolipid extract raised several ceramide subclasses, including AP, EOP, NS and AS, showing the subclasses respond as a group rather than singly.