Lipstick and face cream are widely used leave-on cosmetic products, and their continued contact on the skin and mucosa results in greater opportunity for absorption into the skin. Since cosmetic products are composed of chemicals, use of these products results in exposure to chemicals. Fortunately, the skin has a protective barrier but some product components may penetrate this barrier. For this reason, it is important to evaluate the exposure degree of cosmetic products, to know the safety as well as intrinsic hazard of their components.
Data on factors such as exposure conditions, the formulation or vehicle, and characteristics of the skin, which influence the percutaneous absorption of chemicals and exposure of consumer products, was published in 1993 by the European Center for Ecotoxicology and Toxicology of Chemicals,1 and in 1997 by the U.S. Environmental Protection Agency (EPA).2 Further, studies regarding the exposure degree of cosmetic products have been made by Loretz et al.,3–5 for U.S. consumers, and by Hall et al.,6 for European consumers, but in Korea, no attempt had been made until now to establish the exposure degree of cosmetic products.
One of the objectives of this study was to determine the exposure degree of the two most commonly used cosmetic products—lipstick and face cream— in terms of frequency, i.e., number of uses per day, and amount per use. An additional objective was to compare the results of surveys with data collected by weighing product containers before and after use. This exposure data will be used in future studies, to evaluate the safety of cosmetics and other personal care products and ingredients in Korea.
Materials and Methods
Study design: The present study was carried out in two steps—event attendee surveys and online recruiting. First, data was collected by surveying attendees of the 2009 Cosmobeauty Seoul event. A total of 2,146 attendees were asked where they live, their age, how frequently they use cosmetic products and how long, on average, they wear lipstick and/or face cream. Most attendees were from the regions of Seoul and Gyeonggi-do, 46.0% and 29.9%, respectively, followed by the Incheon region at 10.3%, and were in the age ranges of 20–29 and under 19, 49.8% and 24.3%, respectively; followed by ages 30–39, at 11.7%.
The rate of regular use of lipstick and face cream according to age are shown in Table 1.
In the second step, the target consumer group using lipstick and face cream was restricted to females in two age categories: 20–29 and 30–39. The age category of under 19 was excluded due to high nonuse levels of lipstick and face cream, 39.6% and 49.8%, respectively. Regionally, step two was restricted to the Seoul, Gyeonggi-do and Incheon areas; Incheon was included with Gyeonggi-do for geographical reasons and convenience. In the second step, study subjects were recruited through the home page of the Korean Cosmetic Association website, http://kcia.or.kr, for the targeted consumer group. The women recruited were given specific products as their exclusive lipstick and/or face cream during the two weeks and asked not to share products with others. The subjects recorded frequency of product use daily in a diary provided to them. To gain precise exposure data, subjects were instructed to use the products as they normally would. Lipstick and face cream: The generally available HERA Shine Holica lipstick and Iope Moisture Lasting face creamb were supplied to the study subjects. In the case of lipstick, the study subjects chose their preferred color from No. 106 (peach pink), No. 117 (shine red), No. 136 (shea brown) and No. 125 (syabe orange). A single face cream was used.
Data collection: After two weeks of use, the subjects returned the test products and their reports. The reports were checked for accuracy and completeness and the data was linked to the pre- and post-weight measurement data. Pre and post weighing was conducted for all test products using a scalec measuring to milligram sensitivity.
To compare the results of the survey with the data gained from the target group, the results of the survey were restricted regionally to the Seoul and Gyeonggi-do areas, and only age groups 20–29 and 30–39 years were considered.
Duration of use: The highest response rate was 19.01% of subjects, who reported using 4 g of lipstick over a six month duration. At slightly less, 18.58% of responders reported using the same 4 g over just three months; 14.76% reported the same 4 g use over 12 months. In the age category of 20–29 years, the highest duration was three months for Seoul with 8.25%, and Gyeonggi-do with 7.47%, followed by six months with 7.55% and 7.03% for Seoul and Gyeonggi-do, respectively. In the age category of 30–39 years, the highest responded duration was six months with 2.34% and 2.08% for Seoul and Gyeonggi-do, respectively (see Table 2 on Page 796). The highest response rate for 50 g of the face cream was 24.13% for three months, followed by 18.23% for six months and 11.20% for two months. The response rate of the no-answer group was 19.27%, which is almost two times higher than it was for the lipstick (8.42%). In the age category of 20-29 years, the highest response period was three months for Seoul with 9.81% and Gyeonggi-do with 8.77%, followed by six months with 7.45% and 6.94% for Seoul and Gyeonggi-do, respectively. In the age category of 30–39 years the highest response period was also three months with 3.04% and 2.52% for Seoul and Gyeonggi-do, respectively (see Table 3).
Frequency of use: The highest response rate of lipstick use per day was 25.43% for one application, followed by 15.54% for three; 22.57% of the response was the nonuser group. In the age category of 20–29 years, the highest frequency was once per day, with 10.24% for Seoul and 8.85% for Gyeonggi-do, followed by three times per day with 6.60% and 6.77% for Seoul and Gyeonggi-do, respectively. In the age category of 30–39 years the highest frequency was also once per day, with 3.82% and 2.52% for Seoul and Gyeonggi-do, respectively (see Table 4).
The average frequency of use per day was calculated as 2.43 times. In Seoul, the average frequency of daily use was calculated as 2.40 times and 2.08 times for age categories 20–29 years and 30–39 years, respectively. In Gyeonggi-do, the average frequency of daily use was calculated as 2.65 times and 2.00 times for categories 20–29 years and 30–39 years, respectively.
The highest response rate for face cream in the frequency of use per day was 38.19% for two applications, followed by 31.60% for one application; 16.58% of the response was the nonuser group. In the age category of 20–29 years, the highest frequency per day was two times with 15.36% for Seoul and 13.02% for Gyeonggi-do, followed by one time with 12.33% and 12.41% for Seoul and Gyeonggi-do, respectively. In the age category 30–39 years, the highest frequency was also two times per day, with 5.56% and 4.25% for Seoul and Gyeonggi-do, respectively (see Table 5). The average frequency of use of face cream per day was calculated as 1.73 times. In Seoul, the average frequency of use per day was calculated as 1.75 times and 1.73 times for the age categories 20–29 years and 30–39 years, respectively. For Gyeonggi-do, the average frequency of use per day was calculated as 1.62 times and 1.73 times for age categories 20–29 years and 30–39 years, respectively.
The estimated amounts of lipstick and face cream used per day and per application, as collected by the surveys, were averaged. For convenience, one month was calculated as 30 days and periods of use over 12 months were calculated as 13 months. The average daily application amounts were estimated from the average total amounts used and the number of women who responded. The average total amount used was estimated from the period of use (see Tables 2 and 4) and the average individual amount used daily. The average individual amount used per day was estimated from the amount of product used—4 g for lipstick and 50 g for face cream—and the number of days it was used. The average amount used per application was estimated from the average amount applied daily and the frequency of use per day (see Tables 4 and 5). The estimated average amount of both products used per day and per application is summarized in Tables 6 and 7. The estimated amount of lipstick and face cream are given in milligrams and grams, respectively.
The mean, maximum and minimum values for the average amount of lipstick applied daily were estimated as 33.028 mg, 133.333 mg and 10.256 mg, respectively; per application, the average amounts were estimated as 19.448 mg, 133.333 mg, and 2.051 mg, respectively. The mean, maximum, and minimum values for the average amount of face cream applied per day were estimated as 0.481 g, 1.667 g and 0.128 g, respectively; the average amount used per application was estimated as 0.329 g, 1.667 g and 0.028 g, respectively.
Results of Target Group
Completion rate: Of the 132 subjects recruited, 118 subjects completed the study. In Seoul, 89 subjects completed the study from 97 recruited subjects and in Gyeonggi-do, 29 subjects completed the study from the 35 recruited.
Frequency of daily use and application number distributions: The proportion of subjects using each of the products decreased over the investigation period for the products. The percentage of subjects using products on Day 1 was 96.6% and 100.0% for lipstick and face cream, respectively, but this decreased to 82.2% and 95.8% by Day 14. The decrease could be due to the subjects’ dislike of the test product or lifestyle but the reason was not clear.
The number of applications per day varied depending upon product type. For lipstick, the number ranged from zero to 10, with approximately 89% of respondents reporting three or less applications per day. For face cream, the number ranged from zero to four, with approximately 95% of respondents reporting two or less applications per day. The total investigation estimates were derived by assuming the 14 days contributed by each of the participants represented independent individual days of observation. Thus, in both cases, the total investigation estimates are based on 1,652 total individual days; 14 days for each of the 118 subjects.
Frequency of applied amount distributions: The amount of product used during the investigation was obtained from the difference between the weight of the container before and after the investigation. The actual amount used per application was not directly available. The average amount of product used daily was estimated by the ratio of the amount used to the number of days used. The average amount of product used per application was estimated by the ratio of the total amount used to the total number of applications for the entire investigation. The distribution of the total amount of both products used and the average amount of both products used per day and application are summarized in Tables 8 and 9. The used amount of lipstick and face cream are given in milligrams and grams, respectively.
The mean, maximum and minimum values for the average amount of lipstick applied daily were estimated as 13.654 mg, 84.279 mg and 0.150 mg, respectively; per application estimates were 7.898 mg, 26.220 mg and 0.111 mg, respectively. The mean, maximum and minimum values for the average amount of face cream applied daily were estimated as 0.852 g, 2.536 g and 0.104 g, respectively; per application estimates were 0.527 g, 1.594 g and 0.104 g, respectively.
Discussion and Conclusions
As noted previously, lipstick and face cream are widely used cosmetic products that, as leave-on products, remain in contact with the skin and oral mucosa, resulting in greater opportunity for absorption. Therefore, studies have been made to gain exposure data of these cosmetic products. Loretz et al.3 reported that the mean and median use per application for three products were: face cream, 1.22 g and 0.84 g; lipstick, 10 mg and 5 mg; and body lotion, 4.42 g and 3.45 g. The mean and median daily use, respectively, were: face cream, 0.25 g and 1.35 g; lipstick, 24 mg and 13 mg; and body lotion, 8.70 g and 7.63 g.
This study provided current cosmetic exposure information for commonly used products for risk assessment purposes in the United States.3 The present study focused on the Korean market. The summary statistics data gained from the results of surveys are estimated values, which can be used to represent real world variations and user patterns; however, the summary statistics data gained by directly weighing the products was easier to interpret and give an exact mean value of the amounts used. In comparison with the previously published data, the variability of the estimated results found from the actual use frequency and amounts by individual subjects was as expected.3–5, 7 However, in actual use studies, in the case of lipstick, the comparison of the average amounts used per day by the 10th and 90th percentile of subjects indicated a 13-fold and 11.4-fold difference between the survey and directly collected data, respectively. In the case of face cream, the difference between the 10th and 90th percentile of subjects was not as high, although it still varied, with an 8-fold and 5.2-fold difference for survey and directly collected data, respectively.
The average amount applied daily for lipstick, as obtained by the results of survey and the data collected directly from weighing, were 33.026 mg and 13.654 mg, respectively. Therefore, the average amount applied daily based on surveys was 2.42 times higher than the data collected directly from weighing. In the case of face cream, 0.481 g and 0.852 g were calculated from the results of the survey and the data collected directly from weighing.
In contrast to the lipstick, the average amount applied per day collected from weighing the face cream was 1.8 times higher than the data obtained from the survey. The average amount applied per application showed a similar pattern. In the case of lipstick, the data gained from the survey was 2.46 times higher than the data collected from weighing. For face cream, the data collected from weighing was 1.6 times higher than the data obtained by the survey. This difference between the estimated data from the survey and the actual data collected was higher than expected, so while the survey method may be the better model for representing real use patterns, to estimate the exposure degree for cosmetic products, direct data collection seems to be the better choice.
If one considers that the color of lipstick is influenced by season, and the data of the survey method represents real use patterns, it would seem better to reduce or diversify the total weight of the marketed product to reduce its period of use. In the case of the face cream, it also would seem better to reduce or diversify the weight of the product to prevent a change in quality during the period of use.
Acknowledgements: This study was supported by the Korean Food and Drug Administration; Found No. 09182KFDA592 (2009).
- European Center for Ecotoxicology and Toxicology of Chemicals, Monograph No. 20: Percutaneous Absorption (1993)
- EPA, Consumer products, in Exposure Factors Handbook 3, 16.1–6.40, EPA: Washington, DC, USA (1997)
- LJ Loretz et al, Exposure data for cosmetic products: Lipstick, body lotion and face cream, Food Chem Toxicol 43, 279–291 (2005)
- LJ Loretz et al, Exposure data for personal care products: Hairspray, spray perfume, liquid foundation, shampoo, body wash and solid antiperspirant, Food Chem Toxicol 44, 2008–2018 (2006)
- LJ Loretz et al, Exposure data for cosmetic products: Facial cleanser, hair conditioner and eye shadow, Food Chem Toxicol 46, 1516–1524 (2008)
- B Hall et al, Probabilistic modeling of European consumer exposure to cosmetic products, Food Chem Toxicol 45, 2086–2096 (2007)
- ME Weegels and MP van Veen, Exposure data for cosmetic products: Facial cleanser, hair conditioner and eye shadow, Risk Analysis 21, 499–511 (2001)