Efficacy of a Topical Formulation on Skin Hydration and Barrier Function in Individuals With Xerosis: A 28-Day Randomized, Split-Leg, Untreated-Controlled Trial.

Abstract

Background Xerosis cutis is characterized by impaired epidermal barrier function, increased transepidermal water loss (TEWL), reduced hydration, and symptoms such as pruritus.Aims To evaluate the efficacy, tolerability, and subjective perception of a topical formulation containing panthenol, niacinamide, and dipotassium glycyrrhizate in improving skin hydration and barrier function in subjects with dry, sensitive skin.Methods In this randomized, intra-individual, split-leg clinical trial, subjects with xerosis applied the test emollient twice daily for 28 days to one pretibial area. The contralateral leg remained untreated as control. Assessments were performed at baseline (T0), 30 min, 24 h, 48 h, day 7 and day 28. Primary outcomes were corneometric stratum corneum hydration and TEWL. Secondary outcomes included deep skin conductance ("deep moisturization"), desquamation index, surface microrelief regularity (SEr), scaliness (SEsc), dermatologist-rated clinical signs, and participant self-assessment.Results Thirty-five participants (31 women; mean age 47.3 ± 2.0 years) were included. Compared with baseline (hydration: 21.3 ± 1.0 c.u., 95% CI: 19.3-23.3; TEWL: 9.2 ± 0.3 g/h/m2, 95% CI: 8.6-9.8) and untreated control, the treated leg showed greater corneometric hydration at all time points: 66.2% (33.9 ± 1.4 c.u., 95% CI: 31.1-36.7) at day 7 and 74.1% (35.2 ± 1.2 c.u., 95% CI: 32.8-37.6) at day 28 (all p < 0.001). TEWL decreased by 11.3% (8.2 ± 0.2 g/h/m2, 95% CI: 7.8-8.6) and 13.5% (7.9 ± 0.2 g/h/m2, 95% CI: 7.5-8.3), respectively (all p < 0.05). Deep moisturization increased by 5.7% (39.5 ± 0.9 μS at day 7, 95% CI: 37.7-41.3) and 7.3% (41.1 ± 0.8 μS at day 28, 95% CI: 39.5-42.7) (p < 0.05). The desquamation index decreased by 13.0% (29.50% ± 1.67% at day 7, 95% CI: 26.1-32.9) and 15.8% (26.77% ± 1.25% at day 28, 95% CI: 24.2-29.3), SEr increased by 46.9% (3.38 ± 0.15 a.u. at day 7, 95% CI: 3.08-3.68) and 54.2% (3.47 ± 0.15 a.u. at day 28, 95% CI: 3.17-3.77), and SEsc decreased by 67.0% (0.81 ± 0.12 a.u. at day 7, 95% CI: 0.57-1.05) and 76.3% (0.51 ± 0.07 a.u. at day 28, 95% CI: 0.37-0.65), respectively (all p < 0.05). Dermatologist assessments at all time points showed significant clinical improvement in dryness and pruritus in all participants (p < 0.001). Complete resolution was observed in all participants according to the 5-point scale, though this may reflect a floor effect given mild baseline scores.Conclusions The topical formulation appeared to be an effective and well-tolerated emollient; however, the absence of a vehicle control precludes attribution of effects specifically to the active ingredients. Patient-reported outcomes should be interpreted with caution due to the unblinded design.