HORMONAL CHANGES AND SKIN 315 24 - - - - - - - Estradiol (published) - - - - - Progesterone (Published) 21 � 18 15 12 0 I- 9 11 6 z 3 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Menstrual phase Frolif erative stage Secretory stage Figure l. Hormonal changes in blood over the course of a month. Published levels are the dotted lines with arbitrary units. It is cleat that the increase and reduction of hormones over the course of a month match published data when calculated based on the number of subjects exhibiting the highest levels over the course of the month. rise and fall of the hormones during the menstrual cycle, obtained by Toot et al. (22). In the normal menstrual cycle, progesterone is produced after ovulation (days 15-28), with peaks of 250-2,800 ng/dl of progesterone in serum (22). The levels of estradiol generally reach a maximum one day before the lutinizing hormone (LH) peak, after which there is a marked reduction followed by a rise again during the luteal phase, 5-7 days after ovulation (22) (Figure 1). EFFECT OF SYSTEMIC HORMONAL FLUCTUATIONS ON SKIN Barrier. The effect of the menstrual cycle on skin barrier functions is reported in Figure 2, which displays the histogram of the number of subjects exhibiting the weakest barrier (i.e., the number of subjects who required the lowest number of strippings to disrupt skin barrier at a certain day in the cycle versus the days in the cycle). In Figure 2, the histogram is superimposed onto the published data for progesterone and estradiol levels in serum. It is clear from Figure 2 that most respondents had the worse barrier between days 22 and 26. It must be borne in mind that the deterioration of the barrier was extremely slight, but consistent for the time of the month. Sting. Since all subjects were not stingers, no significant difference in the stinging response over the course of the month could be observed. From Figure 3 it can only be concluded that a subgroup of the panelists (the stingers) seems to have a slightly higher peak in sensitivity between days 2 and 12, thus exhibiting a possibility of higher neuronal response in the proliferative phase. Dry skin. Figure 4 shows the number of subjects exhibiting the driest skin at the different time points during the course of a month. All the subjects had the driest skin during the proliferative phase, with most subjects exhibiting the driest skin during the

316 14 12 e? 10 t 8 I 0 6 4 2 JOURNAL OF COSMETIC SCIENCE I I I I I I ' I I I \ ,, �' - - - - - - Estradiol - - Progesterone ---weakest skin barrier 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Menstrual Riase A-olif erative Riase Secretory Riase. Figure 2. Skin barrier strength in relation to the menstrual phase. The highest number of subjects exhibiting the worse barrier was between days 20 and 27 of the cycle. 14 12 l 10 m 8 0 ... 6 4 , ',,, --� / I \ \ -� Estradiol Progesterone ---Lactic acid sting 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Menstrual Riase Ftotif erative Rlase Secretory Riase Figure 3. Lactic-acid sting sensitivity in relation to the menstrual cycle. Most subjects exhibited the highest sting around days 4-14 of the cycle. Since all the subjects were not stingers, this effect does not appear as clearly correlated to the time of the month. first few days of the menstrual cycle, when estrogen levels are lowest. This is expected because the absence of estrogen does not favor the retention of water. Skin surface lipids. The histogram of the number of high sebumeter scores versus the day of the cycle is reported in Figure 5. The subjects exhibit the oiliest skin from day 9 to day 28. Lipid or sebum production appeared to coincide with the secretion of the luteinizing hormone.