Although cleansing is a major part of many people’s skincare, it often leaves our skin feeling uncomfortably tight. A new study has revealed the mechanisms behind this odd sensation, and it could help cosmetics companies improve the cleansing experience.
The tightness you get after cleansing is easily the worst part of the nighttime routine – instead of feeling nicely purified, it sometimes feels like your skin’s a bit too squeaky clean. This happens because cleansers strip away some of the lipids that help to keep our skin moist, causing the outermost layer of our skin, the stratum corneum, to contract.
But why are we able to perceive this tightening?
Researchers suspected that it involved a particular type of sensory receptor in the skin, known as mechanoreceptors, and used a combination of lab-based experiments, computer modeling, and human trial data to explore this theory.
First, the research team applied six different cleansers and nine different moisturizers on donor skin samples acquired from the cheek, forehead, and abdomen. They measured changes in the stratum corneum after application.
This change data was then plugged into a model of human skin, which would predict the signals that mechanoreceptors would send to the brain – essentially, it would be able to predict which cleansers or moisturizers would make people feel tightness, or not, in their skin.
To confirm the model’s findings, the study compared it to data from human trials, in which people had tested the cleansers and moisturizers and reported how tight their skin felt.
“We plotted what we were predicting against what human subjects were telling us, and it all fell on a straight line. In other words, we were predicting exactly what they were telling us,” said Reinhold Dauskardt, one of the study’s authors, in a statement.
“It was an absolutely remarkable correlation with a very high statistical significance.”
The findings support the idea that when we cleanse and the stratum corneum shrinks, the mechanical forces of this process are indeed detected by mechanoreceptors deeper down in the skin. They feed this information back to the brain, which recognizes the signal as a feeling of tightness.
Whilst understanding the neurological impact of skincare products is interesting enough in itself, the study’s results could also have some real-life impacts on future formulations.
“It provides a framework for the development of new products,” Dauskardt explained. “If you’re doing anything to the outer layer of the skin that’s causing it to change its strain state and its stress state, then we can tell you how that information is transmitted and how it will be understood and reported by consumers.”
Hopefully, that means the cleansers of the future won’t make it feel like your skin’s been pegged behind your ears.
The study is published in PNAS Nexus.