The benefits of retinol for the skin.

The retinol and retinoids in general are also beneficial for individuals with skin imperfections, such as blackheads for instance. Upon application to the skin, retinol undergoes two enzymatic conversions to become retinoic acid, its active form. This latter interacts with retinoic acid receptors (RAR) and retinoid X receptors (RXR). By activating these receptors, retinol triggers a cascade of cellular signals that regulate the expression of certain genes involved in the differentiation of keratinocytes. This action helps to more effectively remove dead cells, thus reducing pore obstruction and the formation of comedones. However, retinol should not be considered an exfoliant: it does not cause peeling of the epidermis, it simply accelerates cell renewal.

Several studies have demonstrated the effectiveness of retinol in combating skin blemishes. Notably, a study conducted in 2009 by NATAKANKITKUL and his team. These researchers aimed to compare the effectiveness of a 0.2% retinol formulation, another containing 5% sodium ascorbyl phosphate, a derivative of vitamin C, and a third containing both actives. This study gathered 45 participants suffering from acne. They were divided into three groups of fifteen people and applied one of the formulations daily for eight weeks. Significant reductions in the number of acne lesions were recorded, particularly among individuals who received the product with retinol and sodium ascorbyl phosphate.

The emergence of brown spots is linked to skin ageing, inflammatory processes and/or exposure to certain external aggressors, particularly UV rays. Hyperpigmentation results from a disruption in the melanogenesis process: melanin, the pigment responsible for the natural colouration of the skin, is overproduced in certain areas, which disrupts the uniformity of the complexion. Retinoids, such as retinol, can help to diminish this hyperpigmentation. This is achieved primarily by accelerating the cellular renewal of the epidermis, allowing for a quicker loss of the melanin contained in the cells of the stratum corneum. It is also suggested that retinoids inhibit the expression of tyrosinase, a key enzyme in melanogenesis, as well as the TRP-1 and TRP-2 proteins, thus interrupting the production of melanin.

Several studies have assessed the depigmenting effects of retinoids. Among them, the one conducted by ERKIERT-POLGUJ and her team focused on formulations with 0.3% and 0.5% retinol. For twelve weeks, 37 volunteers showing signs of photoaging applied one of the two treatments to each side of their face. Various skin parameters, such as hydration, elasticity, and hyperpigmentation were evaluated throughout the study. At the end of the twelve weeks, a significant reduction in hyperpigmentation was measured, for each of the serums.