5 misconceptions about retinol.

No.

Although it may not be visibly apparent, cellular degeneration begins around the age of twenty. This is therefore the ideal time to start incorporating active ingredients that can help prevent skin ageing. Indeed, from our twenties, the production of collagen and elastin, the dermal proteins that underpin the skin and ensure its suppleness and elasticity, begins to decrease. In addition, the synthesis of glycosaminoglycans, such as the hyaluronic acid, also reduces, 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 one's skincare routine from the twenties onwards.

Yes.

In 2018, the European Medicines Agency (EMA) decided to harmonise the contraindications related to pregnancy for medicines 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 re-evaluation of the benefit/risk ratio concerning 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 cellular 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 photosensitising. However, scientific studies regarding the photosensitising 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 should be noted that we are only talking about topical retinoids here as isotretinoin is considered photosensitising by the Food and Drug Administration (FDA), the American agency responsible for monitoring food products and drugs. Nevertheless, despite the lack of evidence concerning the risks of photosensitisation induced by retinol and topical retinoids, it is true that it is preferable 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 isomerisation, dimerisation, or even 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.