No abstract

Lipstick is a key product in the make-up sector. A woman applies lipstick to feel feminine and attractive. The sensation she perceives when she applies the product plays an important role in her attachment to her lipstick. The impact of the ingredients on the sensory properties and the quality of the lipsticks needs to be understood, so that the formulation can be more effective and the sensory properties can be precisely adjusted to the target market. During this study, multidimensional correlations were made between the percentage of ingredients, their physico-chemical specifications and the sensory properties of the raw materials on their own or the lipsticks. The objective of this study is to predict the sensory properties of lipsticks from the physico-chemical specifications of the ingredients. It is in effect quicker to access the physical data than the sensory descriptions. The lipsticks were made using a simplified formula, evaluated in a sensory analysis and their physico-chemical characteristics were measured. The relationships between the sensory properties, the ingredient specifications and their percentage of use in the formula were highlighted. The results confirm the major role of the viscosity of oils and the wax used in the formula on the sensory and mechanical properties of the lipstick. It is therefore possible to modify the sensory properties, for example to adjust the shininess of a lipstick, without altering its mechanical resistance. This opens up opportunities for developing innovative sensory textures in short lead times.Résumé -Relations entre les propriétés sensorielles et les ingrédients gras des rouges à lèvres. L'objectif de cette étude est de prédire la sensorialité des rouges à lèvres à partir des spécifications physicochimiques des ingrédients. En effet, les données physiques sont plus rapidement accessibles que les descriptions sensorielles. À partir d'une formule simplifiée, des rouges à lèvres sont formulés, évalués en analyse sensorielle et leurs caractéristiques physico-chimiques sont mesurées. Les relations entre les propriétés sensorielles, les spécifications des ingrédients et leur pourcentage d'introduction dans la formule sont mises en évidence. Les résultats confirment le rôle majeur de la viscosité des huiles et de la cire sélectionnée dans la formule sur les propriétés sensorielles et mécaniques du rouge à lèvres. Il est ainsi possible de modifier des propriétés sensorielles, par exemple, ajuster la brillance d'un rouge à lèvres, sans en changer sa résistance mécanique. Cela ouvre des opportunités pour développer des textures sensoriellement innovantes dans un délai plus restreint.

The perception of lipstick texture upon application is a key driver of consumer satisfaction. However, formulators may only rely on the absence of knowledge about the relationship between ingredients and product sensory properties. Lipsticks are made of a complex anhydrous mixture that contains about 80% lipids (oils, waxes, and butters). The goal of this work was thus to investigate the combined effect of multiple lipid ingredients on the sensory and physical properties of a cosmetic product such as lipstick. To this end, we first analyzed a typical lipstick formula and its related categories of ingredients. This allowed us to create a simplified, yet realistic lipstick system. Based on this, we formulated 36 lipsticks varying in oil and butter composition according to three mixture designs. All products were evaluated by a panel of sensory experts-with a focus on the slipperiness and melting perception-and analyzed using texture measurements. The physical and sensory results both show that the oils had the strongest impact on the lipstick properties while the impact of the butter was negligible. Moreover, the perceived slipperiness of lipsticks was closely related to the viscosity of the oil mixture present in the formula (R 2 = 0.87). Further analyses of lipstick physicochemical properties by differential scanning calorimetry suggest that the nature and amount of oil influence the crystallization of butter and wax, which could explain the dominant impact of the oils on the sensory and mechanical properties of lipsticks.

The ultimate symbol of femininity, lipstick is often a brand’s most attractive makeup product. First created several thousand years ago, its composition has evolved a great deal since then, particularly in the 20th century, when petroleum and its derivatives were discovered. But today, with the emergence of Clean Beauty, customers are looking to go back to more natural compositions that respect the environment and their health. However, the total substitution of synthetic waxes has inevitably brought with its problems of product stability, lipstick solidity, sweating, incompatibilities and oxidation, which today’s ever more demanding consumers are not ready to accept. Beyond stability, the sensoriality and the performance of lipsticks can be altered by such substitution. The objective of this study is therefore to find plant-based substitutes for synthetic waxes, which do not reduce the stability and the overall quality of lipsticks. To this end, the physicochemical properties of plant-based waxes will first be measured, and the best candidates will then be introduced into an all-natural lipstick formula. Some waxes tested have a value equivalent to synthetic wax on one physico-chemical parameter but are less efficient on another. The mixtures of waxes with oils of different polarities show that no wax is as ubiquitous as petroleum wax. To conclude, none of the waxes evaluated can substitute the synthetic wax weight for weight in a formula.

We have developed a lipstick, the stick of which looks totally transparent. The base, coloured or not, may contain high concentration of actives or fragrances. The present study examines the process of determination of oils and solidifying agents. The selecting criterion include visible spectroscopic measurements to quantify transparency of the formulated product. We have also validated the stick hardness through drop point and breakage measurements. After several investigations, we selected a mixture of oils and solidifying agents. The oil network obtained has been characterized through optical microscopy, transmission electronic microscopy, X-ray diffraction and differential scanning calorimetry. We can show that the final product we obtained is amorphous and its solidity can be explained by chemical bonds formation.