Why do you get pimples after using a new cosmetic product?

The causes of facial blemishes are multifactorial: hyperseborrhea, accumulation of dead cells on the skin surface, bacterial colonization, stress, hormonal factors... In some cases, imperfections can also be caused by the use of new cosmetics, the mechanisms of action of which vary depending on the product. The main factors that explain the appearance of facial blemishes following the use of a new skincare product are as follows:

1. The cosmetic induces a purge.

   Also known as the “rebound effect”, cutaneous purging is a natural process resembling an acne flare-up, manifested by the sudden appearance of pimples in the days following the introduction of a new cosmetic into one's skincare routine. The use of certain exfoliating active ingredients accelerates cell renewal, meaning that cells in the deeper layers of the skin begin to rise to the surface more rapidly, eliminating all dead cells in the process and bringing out all imperfections at once. Without purging, imperfections would come out later, more gradually.

   Several factors can help determine if your new skincare product is causing your breakouts and if it's indeed a purge. Firstly, only certain actives are likely to trigger a purge. These are ingredients that promote skin exfoliation, such as organic hydroxy acids (AHA, BHA, PHA), retinoids, or benzoyl peroxide. Moreover, purging is a temporary phenomenon, typically lasting between one and two months. Finally, breakouts due to a purge tend to be localized in areas already prone to acne. Even though the purge can be quite challenging to endure, it often heralds clearer skin, hence the importance of continuing to use the responsible cosmetic for a few months, provided it is indeed a purge.

2. The skincare product is comedogenic.

   If you notice that you have more breakouts than usual after using a new product, it's possible that it may be comedogenic for your skin. This term refers to the ability of an ingredient or cosmetic to clog the pores of the skin, thereby promoting the appearance of comedones. These are often products with a rich texture that, by forming an occlusive film on the skin's surface, hinder the natural evacuation of sebum.

   It is important to note that the concept of comedogenicity varies from one skin type to another. Indeed, if oily and acne-prone skin types are particularly affected by comedogenicity, dry skin types are almost never confronted with this issue. To determine if your breakouts are due to the comedogenic nature of your new cosmetic product, we advise you to check its INCI list. If a comedogenic ingredient is present in the top three positions, it is likely that the product is indeed the culprit.

3. The skin does not tolerate the product.

   There are times when the skin may be sensitive to an active ingredient and does not tolerate it. The use of cosmetics containing such ingredients can then lead to a negative skin reaction that may resemble a breakout. Allergy-induced blemishes are often slightly different from those caused by a purge or a comedogenic product, typically resembling small red bumps grouped in patches.

   When the epidermis does not tolerate a substance, it initiates a inflammatory response characterized by the activation of T lymphocytes and the release of cytokines and other inflammation mediators. This response leads to vasodilation and an increase in the permeability of blood vessels, allowing fluids, plasma proteins, and immune cells to penetrate into the skin tissues. Redness, swelling, and pimples can then be observed. After the offending cosmetic is removed, the pimples disappear spontaneously.

If you notice pimples after using a new cosmetic product, do not immediately conclude that it is the culprit. As mentioned earlier, there are multiple causes for pimples.

• FULTON J. E. Comedogenicity and Irritancy of Commonly Used Ingredients in Skincare Products.Journal of the Society of Cosmetic Chemists (1989).

• MISRA S. & al. Acne: a prevalent skin condition. World Journal of Pharmaceutical Research (2021).

• GAJBHIYE S. & et al. Review article: skincare through the process of exfoliation. International Journal of Current Science (2022).