Barrier recovery rate varies time-dependently in human skin

The recovery in cutaneous barrier functions, assessed in terms of transepid ermal water loss, 1 h after tape stripping of volar forearm skin in human v olunteers, was investigated at different times over the 24 h day. The barri er recovery rate was significantly lower between 20:00 h and 23:00 h than t hat at other time points. The skin surface temperature and the basal transe pidermal water loss reached their highest values at about 03:00 h (33 6 deg rees C and 0.30 mg cm(-2) h(-1)), while the cortisol lever in the saliva wa s highest at 09:00 h (7.8 pmol mL(-1)), These results suggest significant t ime-dependent variation in cutaneous barrier repair independent of changes in skin temperature and cortisol level.