Retinol is a popular ingredient you'll find in many skincare products, given its benefits. Even though its advantages are well established by research, its regular use can cause irritation in some people when they start using retinol or a product with a high concentration of retinol. Let's examine here the causes of this irritation, as well as ways to avoid it.
Retinol: What are the causes of irritation?
The retinol is used to improve many common skin problems, such as wrinkles and fine lines, pimples, brown spots, dull complexion, and enlarged pores. Although it is an effective ingredient that will give you visible results in a few months, the topical application of retinol often causes undesirable effects , the most common of which is local irritation, clinically similar to a mild contact dermatitis. It can last between four to six weeks (retinization), which is the time it takes for your skin to develop a tolerance.
During the initial phase of use, your skin is getting accustomed to the effects of retinol and may develop a slight irritation (retinoid dermatitis). The inflammatory response induced by retinol is somewhat delayed compared to the classic inflammatory events caused by other external stimuli. Various mechanisms are thought to be involved in the irritation induced by retinol. Indeed, this adverse reaction would potentially be associated with a widespread and ubiquitous inflammation, characterized by the release of pro-inflammatory mediators and the infiltration of immune cells, as well as a disruption of the skin barrier illustrated by a genetic imbalance of factors related to the stratum corneum. Indeed, a study has shown that retinoids induce an increase in the expression of MCP-1, IL-8, IL-12p40, and TNF-α in epidermal cells and fibroblasts, pro-inflammatory mediators responsible for the skin irritation induced by retinol.
Similarly, another study demonstrated changes in the morphology and structure of the epidermis following the application of retinoic acid. Specifically, the stratum corneum exhibited lipid droplets and abnormal cell-cell tight junctions, suggesting an alteration in lipid metabolism and dysfunctional cellular junctions. Indeed, they observed differential gene expression of factors associated with epidermal barrier function (claudins, filaggrin, protease inhibitors, tissue kallikreins, etc.), as well as abnormal keratin maturation (parakeratosis) in a murine model and a keratinocyte cell line during skin irritation induced by retinoic acid. Furthermore, alterations in the balance between proteases and protease inhibitors in the skin lead to inflammatory reactions.
How to prevent irritation associated with the use of retinol?
There are measures you can take to prevent irritations associated with the use of retinol before they occur. However, it should be noted that even at low concentrations, a risk of irritation may arise.
Opt for a retinol treatment containing anti-irritant actives: choose a formula with anti-inflammatory substances that have an inhibitory effect on the secretion of certain pro-inflammatory cytokines induced by retinol. In a recent study, researchers report the development of an anti-irritation formula guided by a genetic analysis, revealing the genetic factors that govern irritation induced by retinol. They propose a formula (glucosamine 0.1%, trehalose 2%, ectoine 2%, sucralfate 0.1%, omega-9 1% and 4-t-butylcyclohexanol 0.7%) that can modulate or mitigate the molecular pathogenesis induced by retinol in vitro. This new approach will allow retinol-based cosmetic products to be more accessible to sensitive skin and skin prone to retinol-induced irritation.
Mixing retinol with a moisturizing cream : you can also blend your retinol treatment with your moisturizing cream. This will both hydrate the skin while reducing the risk of irritation. Indeed, applying retinol at the same time as your moisturizing cream allows it to be diluted without rendering it completely ineffective. This method can help your skin develop a tolerance to retinol without causing irritation.
Preferably look for a moisturizing cream that contains hyaluronic acid, ceramides, or glycerin.
Adopting the "retinol sandwich" method: if you have dry or sensitive skin and you want to incorporate retinol into your skincare routine, you can opt for the "retinol sandwich". Layering topical retinol with a moisturizer will help to temper any skin irritation. This involves applying a first layer of moisturizer right after washing your face, followed by the retinol on top, and sealing it all with a second protective layer.
Opt for another form of retinoid : if you have particularly sensitive skin, prone to rosacea, or if you're looking for a gentler option, you might consider choosing a different type of retinoid (retinol esters, granactive retinol, etc.) that offers similar benefits but with a significantly lower risk of irritation.
Switch to a simple skincare routine during the adjustment period: in order to reduce the risk of developing retinoid dermatitis, go back to basics and abandon masks, peels, and exfoliating scrubs, especially if you have sensitive or dry skin. Indeed, avoid applying other products containing AHA, vitamin C, or salicylic acid during retinization.
MAIBACH H. I. & al. The specificity of retinoid-induced irritation and its role in clinical efficacy. Exogenous Dermatology (2002).
KANG K.-S. & al. The mechanism of retinol-induced irritation and its application to anti-irritant development. Toxicology Letters (2003).
BERGE C. A. & al. Facilitating facial retinization through barrier improvement. Cutis (2006).
LEE A.-Y. & al. Retinoic acid and hydroquinone induce inverse expression patterns on cornified envelope-associated proteins: Implication in skin irritation. Journal of Dermatological Science (2014).
GENG S. & al. All‑trans retinoic acid alters the expression of the tight junction proteins Claudin‑1 and ‑4 and epidermal barrier function‑associated genes in the epidermis. International Journal of Molecular Medicine (2019).