What are ceramides?

Ceramides consist of a long-chain or sphingoid base linked to a fatty acid via an amide bond.

Figure: Sphingosine.

Figure: ceramide, with sphingosine bound to a fatty acid via an amide.

Ceramides are present at low concentration in plants and animals, so there isn’t a good source of natural ceramides for use in the industry. Extraction of a rare chemical from a plant requires laborious processes and the resulting ingredient are terribly expensive. Another source of ceramides, the central nervous system, is not suitable for epidemiological reasons. For this reason, the ceramides used in skin care are synthetic.

Confusing Terminology

The chemical nomenclature for ceramides is simple enough: it combines the names for fatty acids and long-chain bases to denote the molecular species of ceramides, e.g. N-palmitoyl-sphingosine is d18:1-16:0.
For ceramides, the INCI (International nomenclature for cosmetic ingredients) nomenclature is not helpful. For the synthetic ceramide caproyl sphingosine  (about $25,000 per gram, for comparison, the price of pure gold is around $55 per gram), with CAS# 100403-19-8, several INCI names are used: Ceramide 5, ceramide 4, ceramide 3, ceramide 2, ceramide 1, ceramide 1A, ceramide 6, ceramide 6II, etc.
A typical ingredient list of a ceramide mix used in the industry will read as follows: Ceramide 3 (and) Ceramide 6 (and) Ceramide I (and) Phytosphingosine (and) Cholesterol (and) Sodium Lauroyl Lactylate (and) Carbomer (and) Xanthan Gum. Even with additives, this ingredient still cost several thousand dollars per Kg.
The forum question that started this article was “which ceramide does Skin Actives use?” The INCI name for “our” ceramide is “ceramide E”, and CAS No is 153967-07-8
Synonyms: Cetyl-PG Hydroxyethyl Palmitamide and Hexadecanamide, N- (2- hydroxyethyl)- N- (3- hexadecyloxy- 2- hydroxypropyl)-
If you look at the chemical formula below, you will see that this is not strictly a ceramide, thus its name “pseudoceramide”. Pseudoceramides were created to solve the problem created by topical steroids, a medication used for serious inflammatory illnesses; when used long term corticosteroids affect the skin in negative ways. Pseudoceramides are capable of forming lamellar structures like those ceramides form; they will restore the skin barrier, decreasing water loss in skin damaged by corticosteroid use.

Figure: Ceramide E (chemical name Cetyl-PG Hydroxyethyl Palmitamide).

What do ceramides do for our skin?

Ceramides are important to our skin, an important part of what makes the epidermis a good barrier against water loss. They form part of the “cement” that together with flattened, a-nucleated cells (corneocytes) make the cornified layer (stratum corneum, SC) of the epidermis. The SC is central to the role of skin as a barrier against water loss, bacterial and fungal attacks and penetration of anything foreign to the skin.

Figure: Skin layers (from Wikipedia).

The most external layer is the stratum corneum, preventing water loss and entry of noxious substances. How is the stratum corneum formed? In the layer below, keratinocytes are losing their nuclei and releasing polar lipids that will be transformed into ceramides and free fatty acids.

The SC consists of corneocytes, flattened cells that have lost their nuclei, embedded in a lipid mixture consisting mainly of a lamellar structure of ceramides, cholesterol, and free fatty acids.  Insufficient lipids or lipids in the “wrong” ratio (because some were lost or there were not enough in the first place) can result in an increased water loss and/or increased penetration of harmful substances from the environment causing skin dryness and skin sensitivity

Now, we can make a big thing of this and say that we need to plaster the skin with topically applied ceramides in order to improve the barrier, but by the time ceramides are deposited in the epidermis it is a bit too late to change much. In my opinion, the time to work on a good stratum corneum is long before it has been formed: provide your live skin cells with the polar lipids they will use later on to make ceramides.  As for the fundamental role of the SC, the cornerstone of the skin barrier, at this late stage other actives may do just as well.

How do you get ceramides in your daily skincare?

Try our ready-made Nourishing Skin Serum which provides all of the lipids your skin needs, it is 100% active ingredients.

We also offer 1g of Ceramides which can be added to your creams or oils.

-Dr. Hannah Sivak

Claims on this page have not been evaluated by the FDA and are not intended to diagnose, cure, treat, or prevent any disease.