The retinol is a potent active ingredient capable of acting on wrinkles, brown spots, and blemishes. These various actions are primarily due to its ability to stimulate cellular renewal. However, this effectiveness of the retinol comes with a significant risk of skin irritation, particularly during the first weeks of use and in sensitive skin types. Indeed, it is not uncommon to notice redness and slight skin peeling when starting to use a product containing retinoids.
This irritation process is linked to several biological mechanisms. On one hand, retinol accelerates the renewal of keratinocytes, the cells of the stratum corneum, which temporarily disrupts the skin barrier and reduces the amount of certain protective intracellular lipids, such as ceramides or cholesterol. This alteration of the barrier function also increases transepidermal water loss, which heightens the skin's vulnerability to external irritants and environmental allergens and can make it dehydrated. Retinol can also trigger a mild inflammatory reaction, characterised by the release of mediators, such as interleukin-8 (IL-8) and tumour necrosis factor alpha (TNF-α).
How to counteract the irritation associated with retinol?
Retinol-induced irritation is often temporary and does not necessarily require discontinuation of its use. It is often sufficient tospace out the applications, using it every other night, or even every third night, depending on skin tolerance. Additionally, it is also possible to start at a low dose, such as 0.01% or 0.05%, and gradually increase the concentration of retinol. Lastly, the method of the "retinol sandwich", which involves applying the retinol treatment between two layers of moisturising cream, can help to reduce the risk of irritation while gradually acclimatising the skin to this active ingredient.