DRY SKIN BENEFIT FROM IN-SHOWER BODY LOTION 257 However, over half of adult females shower once daily, and this � as chosen as the treatment frequency for the in-shower body lotion use protocol. This study also shows that a high percentage (7 4%) of consumers spend between five and 15 minutes in the shower (Figure 2). Since an in-shower body lotion is applied near the end of the shower, this range represents the period of time an individual's skin is et before the in-shower body lotion is applied. The habits and practices study conducted to establish in-shower body lotion in-use parameters showed that individuals rub the product on their skin for about 20 seconds. Typical residence times, i.e., the amount of time the in-shower body lotion remains on the skin, ranged from 40 to 90 seconds. Finally, typical in-shower body lotion rinse times ranged from 10 to 30 seconds. IN-SHOWER BODY LOTION DOSING The amount of in-shower body lotion consumed during use was quite consistent in the two studies conducted. Per-use consumption was 9.6 ± 0.55 grams (mean± SEM) in the two-week study, 9.8 ± 0.55 grams in the first group of the five-week study, and 10.3 ± 0.44 in the second group of the five-week study. This is the amount of product applied over the surface of the body however, for a controlled application protocol, what is needed is a product dose, i.e., an amount per application area. Consumer feedback from the concept-aided in-home use test shows that nearly 70% of female consumers apply in-shower body lotion to their entire body. Knowing this, adult female body surface area data (13) were used to convert the consumption data to an in-shower body lotion use dose. Data for the 15r\ 50r\ and 85th percentile body surface areas were used to account for body size variation. Additionally, calculations were 60 Cl) 50 E - 40 u Cl) 30 Cl) - - Cl) 20 Cl) 10 0 17 Oto 4 5 to 10 11 to 15 16 Time In Shower (Minutes) Figure 2. Time spent showering based on a study conducted among 1234 representative adult female consumers in the United States. Seventy-four percent of participants spend between five and 15 minutes in the shower.

258 JOURNAL OF COSMETIC SCIENCE Table I In-Shower Body Lotion Doses Calculated From Consumption Study Data Using the 15t\ SOt\ and 85th Percentile Adult Female Body Surface Area Data (13) Two-week study Five-week study Full body surface Reduced body surface Full body surface Reduced body surface Body surface area percentile 0.78 (0.045) 1.0 (0.057) 0.84 (0.026) 1.1 (0.033) 0. 71 (0.041) 0.90 (0.052) 0.75 (0.024) 0.96 (0.030) 0.62 (0.036) 0.80 (0.046) 0.66 (0.021) 0.85 (0.027) The calculations were performed using the full body surface area (arms, legs, full trunk) and a reduced body surface area (arms, legs, half-trunk) to obtain a more conservative dose estimate. Values reported are the mean calculated dose in µl/cm2 standard errors are shown in parentheses. performed for full (legs, arms, trunk) and reduced (legs, arms, half-trunk) body surface areas, the latter being done to provide a more conservative estimate of in-use dose even though habits and practices data indicate full body use in a high percentage of con­ sumers. Dose calculation results are summarized in Table I. Based on these results, an in-shower body lotion dose of 1 µl/cm2 was chosen for the controlled application pro­ tocol. This dose provides a number of uses from a commercial product bottle that is consistent with consumers' experience with the product (Table II) and is consistent with in-use doses reported for products of similar form that are applied to the body, e.g., sunscreens (14, 15 ). PROTOCOL PARAMETERS Wet time. An in-shower body lotion is applied to the skin after cleansing. Thus, the skin is wet for some period of time before the product is applied. A one-day (single appli­ cation) study was conducted to assess the effect of wet time on an in-shower body lotion product's potential to improve dry skin. After controlled cleansing, a water stream was run over the leg for 5, 10, or 15 minutes before in-shower body lotion application, to simulate in-use conditions. Evaluations were conducted one, three, and six hours after application. Wet time did not have a significant effect on the dry skin benefit resulting from in-shower body lotion application at any of these times (Figure 3). Wet time also Table II Predicted Number of Uses From a 250-ml Bottle of In-Shower Body Lotion for Various Doses Dose (µl/cm2) 2 3 4 5 6 Estimated number of uses from a 250-ml bottle 15th Percentile 50th Percentile 8 5th Percentile 20.4 18.5 16.2 10.2 9.2 8.1 6.8 6.2 5.4 5.1 4.6 4.1 4.1 3.7 3.2 3.4 3.1 2.7 Calculations were performed using the 15th, 50'\ and 85th percentile female body surface areas (13). Dosing at 1 µl/cm2 yields a projected number of uses that is consistent with consumer experience.