Retinoids: vain fears
Barriers to prescribing cosmetics with retinoids
According to the recommendations of many associations of dermatology, retinoids are the first choice drugs for skin with acne [1], they also do an excellent job of correcting pigmentation, photoaging and chronoaging [2, 3], improve skin texture, including reducing pore size [4]. By and large, retinoids have been shown to address virtually all major skin aesthetic deficiencies, and the evidence base for them is large.
Tatyana Shalagina, cosmetologist-aesthetician, author of the online project for advanced training of cosmetologists Skinstory Education
However, many professionals are wary of prescribing retinoids, mainly for two reasons: the irritation they can cause, called retinoic dermatitis, and the increased sensitivity of the skin to the sun, known as phototoxicity and photosensitivity. Often there is a categorical ban on the use of this group of substances for sensitive skin or recommendations not to use retinoids in the summer.
Indeed, there is no smoke without fire and, undoubtedly, retinoids have side effects, but it must be taken into account that cosmetics do not use the final active form of vitamin A - retinoic acid or its analogues, but work with precursors. They require transformation in the skin, so they give the cells the opportunity to store and use retinoids not immediately. These substances include retinol, retinaldehyde, retinyl retinoate and others. All these retinoids have a lower stimulating activity, but at the same time a lower irritant potential.
Most of the research that can be relied upon to understand the side effects of retinoids concerns the trans-retinoic acid isomer of retinoic acid, or tretinoin, or its synthetic analogues, such as adapalene. Therefore, to understand how retinoids work in the skin, we have to extrapolate the results of research to retinoids used in cosmetics, since they are converted to retinoic acid anyway. Let us consider in more detail what scientists know about the topic of retinoic dermatitis and photosensitivity, and what practical conclusions can be drawn.
Retinoic dermatitis
Retinoic dermatitis is a type of contact dermatitis characterized by erythema, dryness, scaling, burning, and itching [5]. Until recently, there has been a debate whether skin irritations are the real reasons that retinoids help in the correction of acne and photodamage, since the histological changes after the application of retinoic acid and other non-specific irritants, SLS, glycolic acid, are really similar. However, other studies have shown that retinoic dermatitis is different from ordinary contact dermatitis, and the mechanisms of their occurrence are different [5].
*Full version of the access article in Ukrainian and Russian
First published in PRO Cosmetology by «Cosmetologist #4, 2021