JOURNAL OF COSMETIC SCIENCE 26 previous work. These data clearly show a regeneration or replacement of NMF in the middle layers of the SC four hours after soaking (Figure 1). Figure 2 shows the regenera- tion of citrulline over time over the various tape strip depths. Without the extraction used in previous studies in our laboratory, no signifi cant treatment effects were found at Figure 1. Signifi cant reductions in NMF were observed in the soaked site 30 minutes post-soaking and rebounded to pre-soaking levels or slightly higher by the four-hour post-soak measurement. *Indicates sig- nifi cant difference from the 0.5-hour soak site, p 0.05. Values are displayed as estimated means of the log10 normalized data with errors as ± standard error of the estimated means. These points are drawn from Study 2, tape strip 5. Figure 2. Signifi cant reduction in NMF levels was caused by soaking as measured 30 minutes after the soak, but signifi cant replacement of NMF was only observed in the lower levels of the SC as measured by tape strip depth. *Indicates signifi cant difference from the 0.5-hour soak site, p 0.05 Values are displayed as esti- mated means of the log 10 normalized data with errors as ± standard error of the estimated means.

REGENERATION OF NMF 27 tape 15 in Studies 1 and 2. Tables I and II provide the statistical results in detail. One potential clinical implication of the observed initial decrease in NMF followed by its re- generation is that it is related to the initial sensation of tightness often reported after washing, which generally subsides spontaneously within the fi rst hours afterwards. How- ever, the effects on tightness and other sensory parameters were not tested. In an attempt to further elucidate the changes caused in the SC by the fresh-water soak and their evolution over time, we added pH measurements to our previously published methodology. Skin pH was signifi cantly elevated immediately after soaking but returned to normal within four hours (Table III). Maintenance of the native SC pH has been shown to repair moderate barrier defects (12), and so a natural return to Table I Signifi cant NMF Results, Study 1 Comparison Signifi cant differences By depth, tape 3 Soak at 0.5 versus control soak at 4 hr for Arg only By depth, tape 5 Soak at 0.5 versus control soak at 4 hr for total amino acids, Ser, Gly, His, Arg Cit, Phe Sum of tapes 1, 3, 5 Same as tape 5 Sum of tapes 1, 3, 5, 10 Same as tape 5 Control 1 vs all other tapes for total amino acids, Ser, Gly, His, Arg, Cit, Phe 3 vs all for total, Ser, Gly, His, Phe 3 vs 10 for Arg Soaked, time 0.5 1 vs all other tapes for total amino acids, Ser, Gly, His, Arg, Cit, Phe Soaked, time 4 1 vs all other tapes for total amino acids, Ser, Gly, His, Arg, Cit, Phe 10 vs all other tapes for all amino acids except Cit Time 0.5 indicates the tape strips collected from the soaked sites 0.5 hours after the soak. Time 4 indicates tape strips collected four hours after the soak. Tape strip numbers are listed as numbers only, e.g., 1 for tape strip 1. All comparisons listed are signifi cant at p 0.05. No signifi cant differences were found at strip 1. Table II Signifi cant NMF Results, Study 2 Comparison Signifi cant differences By depth, tape 3 Soak at 0.5 versus control soak at 4 hr for total amino acids, Ser, Gly, His, Arg By depth, tape 5 Soak at 0.5 versus control soak at 4 hr for total amino acids, Ser, Gly, His, Arg Cit, Phe Sum of tapes 1, 3, 5 Soak at 0.5 versus control soak at 4 hr for all except Phe Sum of tapes 1, 3, 5,10 Same as sum of tapes 1, 3, 5 Control 1 vs all for total, Ser, Gly, His, Arg, Cit 10 vs all for total, Ser, Gly, His 1 vs 5, 10 for Phe 3 vs 10 for Arg, Phe Soaked, time 0.5 1 and 3 vs 10 for Ser, Gly, His, Arg 1 vs 5 for Ser, Cit 3 vs 10 for Ser 3 vs all for Cit Soaked, time 4 1 and 3 for total amino acids, Ser, Gly, His, Arg Cit, Phe All comparisons listed are signifi cant at p 0.05. Time 0.5 indicates the tape strips collected from the soaked sites 0.5 hours after the soak. Time 4 indicates tape strips collected four hours after the soak.