Journal September 25, 2026 6 min read

What markers track the stratum corneum?

The stratum corneum is the outermost skin layer and the primary barrier to topical delivery. This page reviews research markers used to track its hydration, barrier function, and penetration in studies of topical and tra

peptides-pro Editorial

The stratum corneum is the outermost layer of the epidermis, a thin, keratinized membrane that serves as the skin's primary barrier. In the research literature, its status is tracked using a set of non-invasive markers: transepidermal water loss (TEWL), stratum corneum hydration (SCH), erythema, and pH. These markers are measured with instruments such as the Corneometer CM 825 and Tewameter, and they appear as endpoints in clinical trials of topical formulations. The stratum corneum is also the rate-limiting barrier for transdermal drug delivery, so its penetration properties are studied with techniques like confocal Raman spectroscopy and mass spectrometry.

The work centres on the skin barrier function and the pathways that regulate its permeability, including the intercellular lipid matrix and the corneocyte envelope. No single receptor family governs all stratum corneum markers; instead, the research spans biophysical measurements and formulation science.

Research Studies

Panthenol, niacinamide, and dipotassium glycyrrhizate in xerosis: a split-leg trial

A 28-day randomized, intra-individual, split-leg trial evaluated a topical formulation containing panthenol, niacinamide, and dipotassium glycyrrhizate in subjects with xerosis cutis. The test emollient was applied twice daily to one pretibial area, while the contralateral leg remained untreated as a control. Assessments included skin hydration and barrier function, with TEWL as a key marker. The study reported improvements in these parameters, but the specific numerical results are not detailed in the available abstract [3].

Hyaluronic acid, glycerol, and sh-oligopeptide-1 in paediatric atopic dermatitis

An emulgel containing hyaluronic acid, glycerol, grape seed oil, Calendula officinalis, aloe vera, and sh-oligopeptide-1 (a synthetic epidermal growth factor) was tested in a randomized, self-controlled trial involving 57 children aged 2–14 with atopic dermatitis. The emulgel was applied twice daily for 10 days to one forearm, with the other forearm as control. Skin barrier parameters—TEWL, stratum corneum hydration, erythema, and pH—were measured. The study reported changes in these markers, but the abstract does not provide the magnitude of effects [4].

Palmitoyl hexapeptide-12: penetration and mechanical interaction in human skin

Palmitoyl hexapeptide-12, a self-assembling peptide, was studied using label-free techniques including orbital trapping secondary ion mass spectrometry (OrbiSIMS) to track its penetration within full-thickness human skin. The research distinguished between sol and gel forms and examined the peptide's mechanical interaction with skin components. This work provides insight into how the peptide distributes across skin layers, but it is an exploratory study and does not report clinical efficacy endpoints [6].

Acetyl hexapeptide-8: skin permeability and efficacy review

A review of acetyl hexapeptide-8 (AH-8) summarized its structure, proposed mechanisms, and skin permeability. AH-8 is often described as a "botox-like" peptide and is used in topical formulations for anti-aging effects. The review focuses on its efficacy and permeability, but as a review, it does not present new experimental data on stratum corneum markers [5].

Glycyrrhizic acid ionic liquid nanomicelles for peptide delivery

Bioactive ionic liquids synthesized from glycyrrhizic acid and oxymatrine were used to form nanomicelles for enhanced transdermal delivery of palmitoyl pentapeptide-4 (PAL-4). The study optimized component ratios and characterized the nanomicelles. This approach aims to improve the solubility and permeability of signal peptides, but the abstract does not report stratum corneum marker outcomes [8].

Coenzyme Q10 and siRNA TNFα in hybrid lipid-polymeric nanoparticles

Hybrid lipid-polymeric nanoparticles were developed for co-delivery of coenzyme Q10 and siRNA TNFα for anti-inflammatory skin therapy. The study aimed to overcome poor skin penetration and simultaneously modulate inflammatory and oxidative pathways. While the formulation targets inflammatory skin diseases, the abstract does not specify stratum corneum marker measurements [2].

Biodegradable STAR particles for enhanced skin delivery

STAR particles with microscopic needles were designed to painlessly puncture the skin and increase permeability. Biodegradable polymer versions were introduced, made from poly(vinyl alcohol) (water-soluble), cellulose acetate (enzyme-degradable), or polylactic acid (hydrolyzable). These particles are intended to enhance drug delivery to the skin, but the abstract does not report stratum corneum hydration or TEWL outcomes [1].

Oral supplement and skin aging parameters: a 56-day exploratory study

A 56-day, single-center, open-label, single-arm exploratory study evaluated within-participant changes in skin-aging parameters after daily oral intake of NatureU® Mind Care BeautyU Caps in adult women. The primary outcome was change in crow's-feet wrinkle count at Day 56 assessed by PRIMOS CR imaging. The secondary outcome was change in stratum corneum hydration at Day 56 assessed by Corneometer CM 825. Additional exploratory outcomes included other wrinkle topography parameters, skin elasticity, radiance, pigmentation, pore-related parameters, dermal thickness and density, and participant-reported skin attributes. This study is registered on ClinicalTrials.gov and provides a protocol-level description; results are not yet available in the abstract [7].

Reference-only studies

Several additional studies inform the broader context of stratum corneum research. A study using in vivo confocal Raman spectroscopy evaluated sunscreen formulas for reducing UV filter permeation into the stratum corneum, focusing on homosalate (molecular weight < 500 Da) and formulation effects [9]. Another developed polymeric azelaic acid-loaded nanocapsules incorporated into tragacanth gum for rosacea treatment, using alternative models [10]. A third described a hexagram prism structure composed of hyaluronic acid and hydrolyzed collagen (Meltryx) as a dissolvable physical micro-disruption platform for topical delivery of hydrophilic cargos [11]. Finally, a chromatographic method was validated for simultaneous determination of bergenin and alpha-lipoic acid in skin penetration studies [12]. These studies contribute methodological and formulation insights but are not centred on stratum corneum markers as primary endpoints.

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