Clinical and in vitro evaluation of new anti-redness cosmetic products in subjects with winter xerosis and sensitive skin

Objective To demonstrate the in vitro activities of panthenol, palmitoylethanolamide (PEA), and niacinamide (NAM) and determine the biophysical properties, clinical safety, tolerability together with efficacy of two developmental anti-redness (AR) formulations containing these ingredients, in alleviating facial redness associated with winter xerosis in healthy volunteers with sensitive skin. Methods The anti-inflammatory and skin protective properties of panthenol, PEA and NAM were evaluated in vitro. The physical properties of the AR formulations were analysed using measurement of water vapour transport rate (WVTR) and infrared spectroscopy. Clinical studies were performed between the months of December and April (2014-2015) with efficacy assessed during the winter. Facial redness, irritation, sensitization potential, photo-irritation, and photo-sensitization were evaluated. Self-assessed adverse reactions were reported in diaries of use. Results Panthenol and PEA reduced prostaglandin E-2, interleukin-6, and thymic stromal lymphopoietin levels in vitro, while NAM induced nicotinamide adenine dinucleotide (NAD) levels and the keratinocyte differentiation markers: filaggrin (2-fold increase, P < 0.001), loricrin (2-fold increase, P < 0.05), involucrin (2 fold increase, P < 0.001) & peroxisomal proliferator activated receptor-alpha (1.5 fold increase, P < 0.05). The two AR products exhibited low WVTR vs. no treatment (P < 0.001) and displayed an ordered lipid structure. The day cream formulation protected against ultraviolet B radiation in vitro. A total of 382 participants were included in clinical studies which showed the AR formulations significantly improved facial redness associated with winter xerosis (Day 29 mean change from baseline: AR day cream 0.77 (P < 0.001); AR serum 0.67 (P < 0.001)). No irritation, sensitization, photo-irritation, photo-sensitization or product-related adverse reactions were observed or reported in the clinical studies. Conclusion The new products significantly improved skin redness associated with winter xerosis in participants with self-perceived sensitive skin. Both products were well tolerated with a suitable safety profile for topical use in subjects with sensitive skin.