Effect of massage on retinol skin penetration.

Topical administration of active substances may be promoted by optimizing not only the vehicle formulation but also the application protocol. The formulation aspects are widely studied in the literature while a few works are dedicated to the development of application methods. In this context, we studied an application protocol usable as a part of skincare routine by investigating the effect of massage on the skin penetration of retinol. Retinol is a lipophilic molecule widely used as an anti-ageing firming agent in cosmetic formulations. Massage was applied to pig skin explants mounted to Franz diffusion cells after or before the deposit of the retinol-loaded formulation. Thetype of skin massage (roll or rotary type) and its duration were varied.The massage protocol had a significant influence on retinol skin penetration. Due to its highly lipophilic character, retinol accumulated into the stratum corneum but, depending on the massage protocol, a significant retinol concentration was obtained after 4 h in epidermis and dermis layers. Results showed that the roll-type massage was significantly more efficient than the rotary process that exhibited little effect on retinol cutaneous penetration. Such results could be interesting for the development of massage devices in association with cosmetic formulations.