While the skin can be extremely resilient, the skin barrier itself is sensitive to several factors like humidity, temperature, and pH, and requires the right conditions to function optimally1,2.
Effect of dryness on the skin
You might have noticed that your skin seems to be more prone to dryness in the winter months. While this may be partly explained by factors like low humidity and fluctuating temperatures (for example, moving from the cold outdoors to heated rooms)3, there are also physical changes happening in the skin. Key skin lipids, including ceramides, which are crucial to the skin’s normal barrier function, appear to be reduced during winter4. Ceramide levels may be reduced by as much as 40%, resulting in a weaker skin barrier that loses water more quickly5.
That’s why it is especially important to moisturise your skin frequently during the winter.
Effect of humidity on the skin
While most studies confirm that low humidity leads to dry skin, others have found that the skin’s barrier function can also be impacted by higher humidity6. High humidity can decrease skin elasticity, increase sebum production and lower skin pH7. What’s more, sudden, dramatic changes in humidity—such as moving from a very humid outdoor environment to a temperature-controlled building—may cause the skin to lose more moisture than normal3.
Even in humid climates, skin can lack hydration. When the skin is not properly hydrated, the outermost skin cells become shrivelled, leading to dry, flaky skin and a weakened skin barrier. A damaged skin barrier is also more susceptible to irritants, which can result in itchy, irritated skin8.