New research unravels the science behind skin sensations from cleansers and moisturizers. By studying skin layers, neural pathways, and user feedback, scientists provide a comprehensive understanding of the biomechanical processes that lead to these subjective experiences.
Many have experienced the sensation of “tightness” from certain cleansers and “softness” from moisturizers. Reinhold H. Dauskardt, the Ruth G. and William K. Bowes Professor in Stanford’s Department of Materials Science and Engineering, and his team sought to uncover the science behind these sensations. They employed in-vitro biomechanical testing, computational neural stimulation modeling, and gathered self-assessments from thousands of participants to uncover the intricacies.
Understanding the Neural Pathways
When a topical treatment is applied, it modifies specific skin layers. This, in turn, triggers cutaneous mechanoreceptors, which send data to slowly adapting type I (SAI) neurons and subsequently, to the central nervous system. Factors instigating such neural responses include the contracting effect of drying cleansers on the stratum corneum, the outermost skin layer. Similarly, the application of lotions or creams can cause swelling of this layer.
Key Findings and Implications
The research revealed a significant link between the physical stress observed in the stratum corneum, whether from post-cleansing drying or moisturizing, and the activity of neurons located much deeper in the skin near the dermal-epidermal junction. Their neural stimulation model further solidified this connection. Predictions from the model regarding SAI neuron firing rates in full thickness skin were in line with feedback about “tightness” from surveys of 2,000 women in France and 720 women in China. Notably, these sensations were reported even 12 hours post-application in some cases.
According to the authors, this research provides a comprehensive framework to fathom the biomechanical neural activation mechanism that drives the subjective experiences of topical skin treatments.
For more on this research, see Sensational Science: Why Our Skin Feels “Tight” After Using a Facial Cleanser.
Reference: “Sensory neuron activation from topical treatments modulates the sensorial perception of human skin” by Ross Bennett-Kennett, Joseph Pace, Barbara Lynch, Yegor Domanov, Gustavo S Luengo, Anne Potter and Reinhold H Dauskardt, 26 September 2023, PNAS Nexus.