Skin health considerations are becoming more complex as research advances. For example, the relatively recent discovery of the skin microbiome has given rise to a magnitude of questions over its interactions with the host immune system. In the absence of this understanding, researchers can follow the old microbiology principle that the environment dictates the microbial population.
With this in mind, the skin’s barrier integrity becomes the focus, as it protects the skin against pathogenic microbes and defines skin health and resilience. Unfortunately, this barrier is often compromised in the face. Indeed, facial skin can be described as a continuum of healthy skin leading to mild skin conditions such as dry skin patches, spots and blemishes. Clinically, dull and lackluster skin or mildly irritated skin reflect the pre-clinical inflammatory stages of dry and oily skin types, respectively.
In relation to skin health, this column explores how a product’s skin feel and visible impact can improve consumer appearance, overall health and comfort in their own skin.
The sensorial feel of a cosmetic product is crucial to consumers, not only for pleasure during use, but also to encourage good compliance with a product regimen and repurchases. Skin feel as a property is difficult to define, however, as it is subjective; for example, healthy skin is described as feeling “comfortable.”
Predicting sensory and texture attributes is also a challenge and in vivo sensory studies can be expensive and time consuming. As such, it is important to understand the formulation factors governing skin feel. Cosmetic products differ in texture, galenic form (gel or emulsion) and composition (key technology; e.g., the polymer used as texturing agent). Sensory analysis also typically gathers panelist insights on attributes such as firmness, stickiness, spreadability and amount of residue.
Regarding the latter, consumers perceive residue left by emulsions as important; indeed, emollients contribute to skin hydration and reduce transepidermal water loss. On the other hand, gels should leave little or no residue. Gel-creams provide consumers with an unexpected texture and a refreshing effect. Taken together, this great diversity of tactile properties in products results in their skin feel.
Many of these perceptions can be confirmed instrumentally by tactile friction measurements.1 Emollients, for example, drive the spreading of a cosmetic product and their sensory effects will correspond with a friction coefficient measurement.2 One non-biological skin modela has also shown a good correlation with in vivo perceptions in predicting residual sensory properties and film stickiness.3
- Savary, G., Gilbert, L., Grisel, M. and Picard, C. (2019). Instrumental and sensory methodologies to characterize the residual film of topical products applied to skin. Skin Res Technol 25(4) 415-423. doi:10.1111/srt.12667
- Savary, G., Grisel, M. and Picard, C. (2013). Impact of emollients on the spreading properties of cosmetic products: a combined sensory and instrumental characterization. Colloids Surf B Biointerfaces 102 371-378. doi:10.1016/j.colsurfb.2012.07.028
- Eudier, F., Hirel, D., Grisel, M., Picard, C. and Savary, G. (2019). Prediction of residual film perception of cosmetic products using an instrumental method and non-biological surfaces: The example of stickiness after skin application. Colloids Surf B Biointerfaces 174 181-188. doi:10.1016/j.colsurfb.2018.10.062
a Bioskin Plate, Beaulax, Co., Ltd., Tokyo