Journal September 26, 2026 5 min read

What markers track the skin barrier?

Transepidermal water loss, stratum corneum hydration and related readouts are the endpoints most often used to characterise skin barrier status in research settings. This page summarises what the current study record sho

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Skin barrier status is most often tracked in research by transepidermal water loss (TEWL), a non-invasive measure of water flux across the stratum corneum, usually reported alongside stratum corneum hydration and, in some protocols, mechanical properties of the skin surface. These readouts are not a single analyte with a sequence or molecular formula; they are biophysical endpoints, and the studies below apply them to compare barrier characterisation between anatomical sites, between populations, and before and after an intervention. Where a study reports a molecular species rather than a physical measurement, that species is named explicitly.

The work centres on the sphingolipid and ceramide composition of the stratum corneum, the structural lipid class most directly associated with barrier integrity, together with the corneocyte and immune signalling pathways that regulate its turnover.

Research Studies

Vernix caseosa retention and atopic dermatitis prevention in newborns

Vernix caseosa is a naturally occurring white, creamy substance covering newborn skin at birth, formed during the last trimester. A registered trial is examining retention of vernix caseosa in newborns as a primary prevention strategy for atopic dermatitis, a chronic inflammatory skin disease beginning in infancy that affects up to one in five children worldwide [1]. The rationale given is that genetic and environmental factors shape skin-barrier integrity and the skin microbiome in early life, and that preventing disease onset is a distinct goal from treating established disease [1].

Peristomal versus non-peristomal barrier characterisation in people with a stoma

An exploratory study is collecting preliminary data on peristomal and non-peristomal skin barrier characterisation in people living with a stoma, using non-invasive procedures during a one-hour appointment [2]. The stated questions concern whether peristomal and non-peristomal skin differ in barrier characterisation, whether peristomal barrier function differs by stoma type (colostomy, ileostomy, urostomy), and whether stoma type or function influences peristomal barrier characterisation [2].

Transcriptomic and drug-analysis approaches to barrier dysfunction in psoriasis

Psoriasis is described as a chronic immune-mediated inflammatory skin disease characterised by epidermal hyperproliferation, skin barrier dysfunction and immune dysregulation [3]. One study integrated drug analysis with transcriptomics, using the psoriasis transcriptomic dataset GSE14905 from the Gene Expression Omnibus, together with psoriasis-related genes and traditional Chinese medicine compound prescriptions, applying differentially expressed gene analysis and functional enrichment [3].

Topical niacinamide riboside and skin NAD+ in facial ageing

Niacinamide riboside, also called nicotinamide riboside, is an endogenous compound and a precursor to the co-enzyme nicotinamide adenine dinucleotide (NAD+). A registered trial of topical niacinamide riboside on signs of facial skin ageing cites prior work reporting that skin NAD+ levels were negatively correlated with age in both males and females, and that aged skin was correlated with increased DNA damage [4]. The proposed strategy is to support skin NAD+ with precursors such as niacinamide riboside [4].

AP collagen peptide and skin hydration in an oxazolone-induced mouse model

Atopic dermatitis is characterised by impaired skin barrier function and Th2-mediated immune responses [5]. In a hairless mouse model of oxazolone-induced AD-like disease, AP collagen peptide, which contains collagen tripeptide, was evaluated for effects on skin hydration and inflammatory responses, with skin hydration and transepidermal water loss among the measured endpoints [5]. This evidence is animal-only.

Curcumin delivery and skin retention in a psoriasis model

Curcumin has been administered cutaneously for psoriasis, but poor skin permeability and retention limit its therapeutic efficacy by that route [6]. Mussel adhesion protein-modified curcumin-loaded ethosomes were fabricated to enhance permeation and retention within skin; the average particle size was 197.17 nm and encapsulation efficiency was 90.84%, with spherical morphology reported [6].

Phytoceramide production in engineered Saccharomyces cerevisiae

Phytoceramides are sphingolipids that support skin barrier integrity and hydration, but their intricate structures and low natural abundance make scalable production difficult [7]. An integrated metabolic engineering and lipidomics study in Saccharomyces cerevisiae applied three strategies: overexpression of SUR2 (sphinganine C4-hydroxylase) to boost phytosphingolipid formation; deletion of SCS7 (ceramide alpha-hydroxylase) to redirect flux toward non-hydroxylated phytoceramides; and overexpression of ISC1 (inositol phospho

Oral collagen peptides and facial barrier integrity in women

A clinical study is testing whether two different doses of collagen-derived peptides taken for three months improve facial skin barrier integrity in women with dry, sensitive skin, compared with placebo [8].

Comparison of marker types across study designs

Marker or readout	Study design	Population or model
Transepidermal water loss, skin hydration	Animal intervention	Hairless mice, oxazolone-induced AD-like skin [5]
Barrier characterisation, non-invasive procedures	Exploratory observational	People living with a stoma [2]
Facial skin barrier integrity	Randomised, placebo-controlled, two doses	Women with dry, sensitive skin [8]
Skin NAD+ levels, DNA damage	Topical intervention trial	Facial skin ageing [4]
Differentially expressed genes, enrichment	Transcriptomic dataset analysis	Psoriasis dataset GSE14905 [3]
Particle size, encapsulation efficiency	Formulation characterisation	Cur-MAP-Es, 197.17 nm, 90.84% [6]
Phytosphingolipid flux	Metabolic engineering, lipidomics	Saccharomyces cerevisiae [7]

Supporting observations from regimen and ingredient studies

Additional work in the record examines barrier repair and anti-ageing endpoints for topical regimens combining niacinamide, Pro-Xylane and panthenol after PicoWay laser in a randomised controlled design [9]; for a mixed-culture ferment extract of Thermus thermophilus and Bacillus subtilis augmented by tripeptide GHK-Cu [10]; for a hydrogel facial mask based on poly(N-vinyl pyrrolidone) and poly(ethylene glycol) evaluated for hydration, barrier function and mechanical properties in sensitive skin [11]; and for carboxymethyl beta glucan as a driver of skin repair through epithelisation [12]. These support the broader picture that barrier endpoints are applied across topical, oral and formulation contexts.

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