MIAMI Differences in lip color vary by ethnicity and with aging, according to a study presented at an international symposium sponsored by L'Oreal Institute for Ethnic Hair and Skin Research.
"We have a large range of skin tones in the world, but we also have a wide range of lip shades," said Diane Baras, an engineer at L'Oreal Inc. in Chevilly-Larue, France.
Ms. Baras and her associates compared 914 women. They measured lip hue (red/orange color), intensity (chroma/color saturation), and lightness among 238 American black, 238 American white, 225 French white, and 213 Japanese women. All participants were adults between the ages of 18 and 65 years.
The researchers also assessed properties of the perioral skin just below the left corner of the mouth. Younger and older participants were compared to determine how aging affects the lip and perioral skin.
Investigators used the L'Oreal Chromasphere diffuse lighting system to quantify color properties, a corneometer to measure dryness of the lips, and front and profile photographs to assess lip height and plumpness.
"There are some ethnic differences, which emphasizes how we need individualized products for different women," Ms. Baras said at the meeting, which was also sponsored by Howard University.
In terms of hue, lips were strongly redder than perioral skin. This was a positive finding, she said, because "a lot of women want to have a high contrast between the vermilion zone" and perioral skin. In contrast, the hue of the skin was more yellow.
There was no significant difference in chroma or color saturation between the lips and perioral skin.
Lightness did vary in the study. The vermilion zones are always darker than the perioral skin, except in African American women, Ms. Baras said.
Capacitance was measured with a corneometer. Capacitance, which reflects the water content in the skin, was significantly stronger in the vermilion zone, compared with the perioral skin. In addition, there was a "big difference" in transepidermal water loss measured with a VapoMeter, she said. The lower lip lost significantly more water than did perioral skin. Interestingly, this water loss did not significantly differ with age, she noted.
Aging did modify other lip and skin properties. The findings were based on comparisons among an equal number of participants in the 18- to 35-year, 36- to 50-year, and 51- to 65-year age ranges.
For example, there was a decrease in lightness with aging. "A lot of older women will say their lips become pale, that there is 'no life' [to their lips] anymore," Ms. Baras said. "We know they are not pale, because they become darker. But the chroma decreases, so there is a loss of radiance."
Age-related morphology changes also were revealed. There was a strong decrease in the height of the mouthan average of 3 mmbetween younger and older white women, and an even more pronounced decrease of 3.5 mm among American black women.
There was a strong decrease in lip plumpness as well. With age, "lips lose some substance, vitality, and some life," Ms. Baras said.