Creative Touch Permanent Makeup and Aesthetics

Ceramide AP is a phytosphingosine ceramide whose alpha-hydroxy fatty acid chain gives it a distinct chemical polarity among stratum corneum lipids. Where Ceramide EOS and EOP anchor the long periodicity phase, AP’s primary structural contribution lies in the short periodicity phase (SPP), the complementary ~6nm lamellar structure that forms alongside the LPP in healthy barrier tissue. Its elevated polarity and phytosphingosine backbone extend its role beyond passive structure into active skin biology, contributing to anti-inflammatory signalling, antimicrobial defence, and natural moisturising factor production. ^[1]

SPP: The Overlooked Half of Barrier Architecture

Most discussions of ceramides and barrier function rightly focus on the LPP because it is unique to human skin and responsible for the tightest waterproofing. But the SPP is not simply a secondary structure. Research using simplified lipid model systems found that in a mixture of Cer[EOS], Cer[AP], and cholesterol, AP exerted a dominant organising influence, directing lipid assembly into a short periodicity bilayer arrangement of approximately 4.8nm rather than allowing LPP formation. EOS itself was incorporated within this AP-driven SPP structure rather than forming its characteristic LPP. This finding reveals that AP is not a passive filler ceramide: it actively shapes lamellar architecture and holds significant organising power within its phase. ^[3]

In the full physiological lipid mixture, where all ceramide subtypes are present in their natural proportions, both lamellar phases coexist. The LPP handles the most demanding barrier work at low water-content regions of the stratum corneum, whilst the SPP contributes throughout the full lipid matrix. AP’s consistent presence across this wider structure is what makes its depletion consequential even when EOS and EOP levels appear adequate.

The Phytosphingosine Advantage

Ceramide AP, Ceramide NP, and Ceramide EOP all share the phytosphingosine sphingoid base, which carries an additional hydroxyl group at C4 compared to the sphingosine base in NS, EOS, and related subtypes. This extra hydroxyl group increases hydrogen bonding capacity at the head group region of the lipid lamellae, contributing to tighter lateral packing, and carries significant biological activity independent of structural function.

Phytosphingosine has well-established anti-inflammatory and antimicrobial properties, and research has demonstrated that it stimulates epidermal differentiation and modulates filaggrin metabolism. Filaggrin is the protein that breaks down into the building blocks of natural moisturising factor (NMF), the suite of hygroscopic compounds within corneocytes that maintain intracellular water content. Phytosphingosine treatment has been shown to increase pyrrolidone carboxylic acid (a key NMF component) and measurable skin hydration in human subjects, through this filaggrin pathway. This means AP’s contribution to skin hydration operates at two levels: physical lipid barrier structure, and the biochemical support of NMF formation. ^[1]

What makes phytosphingosine ceramide balance clinically meaningful is what happens when it shifts. In inflammatory skin conditions including atopic dermatitis and psoriasis, the balance between sphingosine ceramides (NS, EOS) and phytosphingosine ceramides (NP, AP) changes measurably: phytosphingosine ceramides decline relative to their sphingosine counterparts. A 2023 study from Leiden University used lipid model systems to replicate the NS:NP ratios found in both healthy and diseased skin, finding that the diseased-skin ratio produced significantly higher transepidermal water loss even when lamellar organisation in the LPP remained structurally intact. This suggests phytosphingosine ceramides support barrier function through mechanisms that go beyond, and are partially independent of, lamellar phase architecture. ^[2]

Adaptive and Seasonal Role

AP is notable for an adaptive behaviour that most ceramide subtypes do not demonstrate clearly. Research has found that AP ceramide levels increase in healthy skin during winter months, suggesting the stratum corneum upregulates this specific subtype in response to cold, dry conditions and the increased barrier stress they create. This seasonal responsiveness is consistent with AP’s structural role in maintaining SPP integrity under stress, and with the anti-inflammatory properties of its phytosphingosine base in managing the low-grade inflammation that cold weather and indoor heating provoke.

At Creative Touch, this seasonal pattern informs how we advise clients on barrier support through autumn and winter. The mild exfoliating character of AP’s alpha-hydroxy fatty acid chain also makes it a useful component in formulations intended for clients whose skin is simultaneously barrier-compromised and showing uneven texture from disrupted corneocyte shedding. Products that include AP alongside NP, EOS, and EOP address both the SPP and LPP structural layers, the phytosphingosine-dependent biological pathways, and the surface renewal function that single-ceramide formulations simply cannot replicate.