Enhancement of LipMoistureThrough the use of
Copolymer and Lamellar GelLipsticks.
Sal Barone*, Lambros Kromidas Ph.D.*,
Lenore Coyleand Domnica Cernasov
Coty Inc.
410 American Road
Morris Plains, NJ 07950 USA
* Authors to whom correspondence should be addressed to.
Objectives:
Women are always interested in improving the lip’s appearance and condition. The desire for plump moist lips is a high priority among woman consumers. Moist lips have a plumper and healthierappearance. Also,lip condition is related to lip moisture. Therefore,maintaining or increasing lip moisture, byminimizing water loss from the lips will result in improved lip condition andappearance.
The lip skin, known as the vermilionzone, is composed of a dermis and an epidermis. The lip skin barrier function is vital to having healthy moist lips. All three lipsticks studied will provide some degree of lip barrier reinforcement that will result in more skin hydration. Conventional lipsticks of ozokerite and candelilla wax with a castor oil system should increase moisture by occluding the vermilion zone. The loss of lipids from the vermilion zone leads to loss of barrier function. The lamellar gel type (glyceryl stearate, behenyl alcohol, palmitic acid, stearic acid, lecithin, myristyl alcohol and cetyl alcohol) lipsticks work by replenishing this loss. The copolymer gel type of lipsticks are based on a gelled oil which when placed on lips is less fluid than the conventional lipstick oil system and therefore remains on the lips longer. This contributes as a barrier towards moisture loss.
The objective of this study was to examine the lip hydration (moisturization) properties of three lipstick types; conventional, conventional containing a lamellar gel, and copolymer gel type.
Methods:
The conventional lipstick was composed of an ozokeriteand candellia wax matrix. This matrix is used to hold the castor oil based color grind and oil system. The lamellar gel lipstick has the same base as the conventional lipstick with the addition of(glyceryl stearate, behenyl alcohol, palmitic acid, stearic acid, lecithin, myristyl alcohol and cetyl alcohol) replenishing this loss. The copolymer lipstick is a non-conventional lipstick based on a gelled oil and polymeric wax.
Twelve female subjects between the ages of 20-50 participated in the study. Seven subjects wore the copolymer sample and the conventionalandfive subjects wore the lamellar gel sample and the conventional. Each subject wore two lipsticks for four days in a horizontal split lip fashion for a minimum of eight hours per day. The lipsticks were applied three times per day as follows: 8:30 AM, 1:00 PM, and 5:00 PM. Lip moisture readings were taken on each side of the lower lip in triplicateusing theNovameter 9020 Petite (NOVA Technology Corporation, Portsmouth, NH). Subject readings were taken after the last application was removed on day one and four. Immediately prior to each reading, the lips were gently blotted using Kimwipes EX-L (Kimberly-Clark).
Results:
All three types of lipsticks: conventional, copolymer, and lamellar gel, demonstrated an increase in lip hydration over the course of four days. The conventional lipstick showed the smallest increase (Figure 1). The percent increase in hydration for the three lipsticks from day one to day four was, 6.2 for the conventional, 48.7 for the copolymer, and 53.2 for the lamellar gel.
The change in lip hydration relative to the conventional lipstick was better for the lamellar gel lipstick at day one and day four (Figure 2). At day one the lamellar gel lipstick was 10.59 fold higher and at day four 50.57 fold higher. The copolymer type lipstick was 3.14 fold higher at day one and 8.55 fold higher at day four. The lamellar gel type of lipstick showed a 3.4 fold higher potential for lip hydration over the copolymer type of lipstick at day one and a 5.9 fold increase at day four.
Conclusions:
We have demonstrated that the copolymer and lamellar gel type of lipsticks have a higher potential for lip hydration (moisturization) over conventional type of lipsticks. We have shown that the hydration potential of conventional lipsticks is greatly enhanced (~50 fold higher) within four days if modified by adding (glyceryl stearate, behenyl alcohol, palmitic acid, stearic acid, lecithin, myristyl alcohol and cetyl alcohol). The moisturization potential is even 5.9 fold greater than the unconventional type (copolymer) lipstick within the same use period.