Effective treatment for sensitive skin: 4-t-butylcyclohexanol and licochalcone A

BackgroundMore than 50% of adults report to suffer from sensitive skin. This common condition is characterized by subjective sensations such as prickling, burning, skin tightness or pruritus, and is often accompanied by objective symptoms like inflammation and erythema. ObjectiveThe objective of this study was to develop an active ingredient concept for the treatment of sensitive skin. We tested compounds regarding their potential to (i) decrease the release of proinflammatory mediators, which among others induce erythema and (ii) counteract the hyperresponsiveness of nerve fibres and, thus, exert effects on cutaneous neurosensory dysfunction. Methods4-t-butylcyclohexanol, licochalcone A and acetyl dipeptide-1 cetyl ester were analysed invitro regarding their potential to (i) decrease the release of PGE(2) and activation of NFB and to (ii) inhibit TRPV1 activation or the release of neuronal CGRP. To assess subjective and objective symptoms of skin sensitivity invivo, two controlled, single-blind, randomized studies were conducted with 4-t-butylcyclohexanol and the combination with licochalcone A. ResultsIn vitro, 4-t-butylcyclohexanol significantly reduced TRPV1 activation, while acetyl dipeptide-1 cetyl ester had no effect on receptor activation. Licochalcone A significantly decreased NFB signalling and PGE(2) secretion, at lower concentrations than acetyl dipeptide-1 cetyl ester. A formulation containing 4-t-butylcyclohexanol showed a significant immediate anti-stinging/anti-burning effect invivo, and a cream base containing a combination of 4-t-butylcyclohexanol and a licochalcone A-rich licorice extract reduced shaving-induced erythema. ConclusionIn vitro and invivo data indicate that the combination of the TRPV1 antagonist 4-t-butylcyclohexanol and the potent anti-inflammatory licochalcone A provide an effective active ingredient concept for the treatment of sensitive skin, as the topical application resulted in an immediate relief from symptoms such as erythema and stinging.