Some cleansers and moisturizers have distinct effects on the skin, with cleansers often making the skin feel “tight,” while moisturizers leave it feeling “soft.” Reinhold H. Dauskardt and his colleagues delved into the underlying mechanisms responsible for these sensations. To uncover these mechanisms, they employed a combination of in-vitro biomechanical testing, computational neural stimulation modeling, and self-assessment surveys conducted by thousands of participants.
When a topical treatment is applied to the skin, it can induce changes in specific skin layers. These changes trigger the activation of cutaneous mechanoreceptors, which relay information to slowly adapting type I (SAI) neurons and subsequently to the central nervous system. The alterations that set off this neural cascade can be linked to processes such as the drying effect of cleansers, which cause the contraction of the outermost skin layer, known as the stratum corneum. Conversely, the application of creams or lotions can lead to swelling of the same layer.
The authors of the study discovered robust correlations between the physical stress experienced by the stratum corneum during post-cleansing drying or moisturizing and the firing rate of neurons located deeper within the skin, near the dermal-epidermal junction. By employing their neural stimulation model, they successfully predicted the firing rates of SAI neurons in full-thickness skin, and these predictions closely aligned with the subjective reports of “tightness.” These subjective reports were gathered through surveys conducted with 2,000 women in France testing moisturizers and 720 women in China testing cleansers, with some effects still being reported up to 12 hours after application.
This research presents a quantitative framework that elucidates the biomechanical neural activation mechanism underpinning the subjective experiences associated with topical skin treatments, as observed by the authors.
Reinhold Dauskardt
Stanford University, Stanford, California
[email protected]
Office: +1 (650) 725-0679
Cell: +1 (415) 297-0201
Gustavo S. Luengo
L’Oréal Research and Innovation, Aulnay sous Bois, FRANCE
[email protected]
Office: +33 634465245
Anne Potter
L’Oréal Research and Innovation, Aulnay sous Bois, FRANCE
[email protected]
Office: +33 661445375
