Journal September 27, 2026 6 min read

How Transepidermal Water Loss Changes with Age

Transepidermal water loss (TEWL) is a key measure of skin barrier function. This page examines how TEWL changes with age and reviews research on interventions that may influence it.

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What is transepidermal water loss?

Transepidermal water loss (TEWL) is the passive diffusion of water through the stratum corneum, the outermost layer of the skin. It is measured in grams per square meter per hour (g/m²/h) and serves as a functional indicator of skin barrier integrity. Elevated TEWL is a hallmark of impaired barrier function, as seen in conditions such as atopic dermatitis (AD) and xerosis cutis [1][3].

The research on TEWL and aging centers on the skin's barrier and its interaction with the immune system, particularly Th2-mediated inflammatory pathways implicated in AD [2].

Research Studies

Vernix caseosa retention and atopic dermatitis prevention in newborns

Vernix caseosa is a naturally occurring, white, creamy substance that covers the skin of newborns at birth. It forms during the last trimester of pregnancy and is thought to contribute to skin barrier development and microbiome establishment. A clinical trial is investigating whether retaining vernix caseosa after birth, rather than cleaning it off, can prevent the development of atopic dermatitis in infancy. The study focuses on primary prevention, aiming to intervene before the disease starts, given that AD affects up to one in five children worldwide and is linked to skin-barrier integrity and the skin microbiome during early life [1].

AP collagen peptides and skin hydration in a mouse model of atopic dermatitis

In a study using hairless mice with oxazolone-induced AD-like skin lesions, researchers evaluated the effects of AP collagen peptide (APCP), which contains collagen tripeptide (CTP), on skin hydration and inflammatory responses. The model exhibits impaired skin barrier function and Th2-mediated immune responses, similar to human AD. The study measured skin hydration and transepidermal water loss to assess barrier function. The findings are animal-only and may not directly translate to humans [2].

Topical formulation and barrier function in xerosis: a split-leg trial

A randomized, intra-individual, split-leg clinical trial assessed a topical formulation containing panthenol, niacinamide, and dipotassium glycyrrhizate in subjects with xerosis cutis. Participants applied the emollient twice daily for 28 days to one pretibial area, while the contralateral leg served as an untreated control. Assessments included transepidermal water loss (TEWL) and skin hydration. The study aimed to evaluate efficacy, tolerability, and subjective perception in dry, sensitive skin [3].

NPQ Plus supplementation and skin health in healthy adults

A single-arm, open-label study investigated the effects of NPQ Plus, a multi-component nutraceutical containing polyphenols (Oligonol®), nicotinamide mononucleotide (NMN; RevAge®), pyrroloquinoline quinone (PQQ; PureQQ®), coenzyme Q10 (CoQ10), and a trace mineral complex (Ioniplex), on skin health, antioxidant status, fatigue, and well-being in 55 healthy adults with skin concerns. Participants consumed one sachet daily for 12 weeks, with assessments at baseline and weeks 4, 8, and 12. The study did not specifically focus on TEWL or age-related changes [4].

Emulgel for pediatric atopic dermatitis: a randomized self-controlled trial

In a randomized, self-controlled trial, 57 children aged 2–14 with AD applied an emulgel containing hyaluronic acid, glycerol, grape seed oil, Calendula officinalis, aloe vera, and sh-oligopeptide-1 (a synthetic epidermal growth factor) twice daily for 10 days to one forearm, with the other forearm as control. Skin barrier parameters including transepidermal water loss (TEWL), stratum corneum hydration (SCH), erythema, and pH were measured. The study examined the emulgel's effectiveness in treating pediatric AD [5].

Oral collagen peptides and skin aging parameters in women

A randomized, double-blind, controlled trial evaluated whether daily oral intake of a collagen peptides supplement improved age-associated skin parameters in 68 healthy women aged 35–65 with visible facial wrinkles. Participants were allocated 1:1 to receive either an active control (n=34) or avvera™ (n=34). One participant in the control group withdrew, leaving 67 completers. The study assessed skin properties and aging hallmarks, though TEWL was not specified as a primary outcome [6].

Vitamin K2 (MK-7) cream and skin hydration in a split-face/neck trial

A clinical trial is evaluating a facial and neck cream containing Vitamin K2 (MK-7) in 36 women aged 35–60 with concerns of facial dryness, dullness, laxity, and neck lines. The study aims to determine if the test cream improves skin hydration (Corneometer), reduces transepidermal water loss (Vapometer), and enhances elasticity and firmness (Cutometer) compared to a control cream. It also assesses wrinkle severity using optical imaging. This trial directly measures TEWL as an outcome [7].

Mushroom extract formulation during breast radiotherapy

A study evaluated a mushroom extract-containing topical cosmetic formulation for skin care in women receiving radiotherapy to the breast after breast-conserving surgery. Participants were randomized to the investigational formulation or usual moisturizing care. The product was applied to intact skin twice daily, starting about 15 days before radiotherapy, continuing through the ~3-week treatment, and ending 1 month after. Skin condition was assessed, but TEWL was not a specified endpoint [8].

Reference-only studies

Several additional studies provide context but are not the focus of this page. A multicenter investigation evaluated temporally optimized antioxidant serums for daytime defense and nighttime repair in sensitive skin, linking oxidative stress and barrier dysfunction to skin biorhythms [9]. Another randomized controlled study assessed a comprehensive topical regimen incorporating niacinamide, Pro-Xylane, and panthenol after PicoWay laser for barrier repair and anti-aging effects [10]. A pilot study examined the long-term effects of a hydrogel facial mask on hydration, barrier function, and mechanical properties in sensitive skin [11]. A real-world longitudinal study explored outcomes of a digital standardized skin care regimen in acne-rosacea comorbidity, using cross-lagged and mediation analyses to understand the clinical-barrier temporal sequence [12].

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