The efficacy of synthetic pseudo-ceramide for dry and rough lips

Lips can easily become dry and rough, one reason being the characteristics of their ceramide (CER) profile. Lips have lower levels of total ceramides, higher percentages of CER[NS] and CER[AS], and lower percentages of CER[NP] and CER[NH] than skin in other regions of the body. The purpose of this study was to clarify the effects of synthetic pseudo-ceramide (pCer; Cetyl-PG hydroxyethyl palmitamide) to improve the dryness and roughness of the lips of healthy subjects in a formulation that exclude an occlusive effect.

Thirty-one Japanese female subjects with normal skin (age range 21-37 years; mean 28.6) were enrolled in this study. A four-week continuous use test was conducted using samples with or without 0.5% or 2.0% pCer. The degree of lip roughness was scored, and values of capacitance, transepidermal water loss (TEWL) and lip surface elasticity were measured. Endogenous CER profiles and absorption levels of pCer in the stratum corneum (SC) were analysed in tape-stripped skin specimens.

Treatment with the pCer-2.0% sample significantly improved the visual roughness score after 2 and 4 weeks compared to 0 weeks and compared to the Blank. Moreover, an improvement in TEWL was observed after 4 weeks of treatment with the pCer-2.0% sample. CER[NP] showed a significant increase in pCer-2.0% treated lips after 4 weeks compared to the Blank. Both pCer-0.5% and pCer-2.0% were significantly absorbed after 2 weeks compared with the Blank.

The effect of the synthetic pseudo-ceramide pCer to improve the roughness of lips was shown excluding the effect of occlusiveness derived from the formulation for the first time. Since the improvement of TEWL and absorption of pCer was observed, we concluded that pCer was first absorbed in rough lip areas, improved the ceramide profile and consequently restored the barrier function.