5 misconceptions about retinol.

No.

Although it may not be visibly apparent, cellular degeneration begins around the age of twenty. This is the ideal time to start incorporating active ingredients that can help prevent skin aging. Indeed, from the twenties, the production of collagen and elastin, the dermal proteins that underpin the skin and ensure its flexibility and elasticity, begins to decrease. In addition, glycosaminoglycans, such as hyaluronic acid, also see their synthesis reduced, making the skin more prone to dehydration, volume loss, and the appearance of wrinkles and fine lines.

It is entirely possible and relevant to incorporate retinoids into your skincare routine starting in your twenties.

Yes.

In 2018, the European Medicines Agency (EMA) decided to standardize the contraindications related to pregnancy for medications containing a retinoid, whether they are administered orally or topically.

Before this update, only oral forms of retinoids, such as isotretinoin, better known by the drug name Roaccutane, were formally contraindicated due to their proven teratogenic effects that could lead to severe congenital malformations. However, following a reevaluation of the benefit-risk ratio regarding retinoids as a whole, the EMA has extended this contraindication to topical retinoids. Indeed, these molecules play a role in embryogenesis and reproduction.

From a mechanistic perspective, the teratogenic effects of retinoids are caused by changes in cell migration and differentiation. More specifically, isotretinoin disrupts the movement of neural crest cells, a cell population crucial for the development of the nervous system, which can lead to their cell death. This disruption explains the occurrence of malformations in craniofacial, cardiac, and thymic structures characteristic of retinoids. Additionally, retinoids affect brain development, particularly in the rhombomere region, involved in the formation of certain parts of the central nervous system. This can result in severe abnormalities, such as cerebellar hypoplasia, meaning insufficient development of the cerebellum, or a malformation of the spinal cord. These effects can harm brain functions and affect intellectual and motor development. Although no study has been specifically conducted on retinol, the same precautionary principle applies to this derivative of vitamin A: this active ingredient should not be used during pregnancy.

Yes.

It is often said that retinol and retinoids in general are photosensitizing. However, scientific studies regarding the photosensitizing potential of topical retinoids do not support this claim and fail to show that the application of retinoids makes the skin more sensitive to the sun. It's important to note that we're only discussing topical retinoids here, as isotretinoin is considered photosensitizing by the Food and Drug Administration (FDA), the American agency responsible for monitoring food and drug products. Nevertheless, despite the lack of evidence concerning the photosensitization risks induced by retinol and topical retinoids, it is true that it is better to use these active ingredients in the evening.

Indeed, like all retinoids, retinol is a molecule that contains numerous conjugated double bonds in its chemical structure. This characteristic makes these compounds susceptible to undergoing photochemical reactions, such as isomerization, dimerization, or oxidation. Therefore, when exposed to sunlight, the retinol present on the skin's surface can transform into various reactive intermediates that can be harmful to the skin. That's why it's recommended to apply retinol and retinoids in general at the end of the day and to use sun protection the following morning.