4 reasons to exfoliate your skin.

On the surface of the epidermis, keratinocytes, the main cells of the stratum corneum, follow a continuous renewal cycle. By migrating from the deeper layers toward the stratum corneum, these cells differentiate and then enter apoptosis, a programmed cell death process. Normally, these dead cells are gradually shed through the natural desquamation process, but over time, the skin aging, oxidative stress or certain environmental insults, they can accumulate on the skin’s surface. As the skin thickens, it reflects less light, resulting in a dull, fatigued-looking complexion.

The exfoliation precisely helps to reactivate this natural elimination mechanism. By removing dead cells, it refines the skin’s texture and reveals a brighter complexion. This effect can be achieved through mechanical exfoliation, using treatments with granules that physically lift off corneocytes, or through chemical exfoliation. The latter relies on active ingredients capable of breaking intercellular bonds, particularly those involving glycoproteins in the stratum corneum. By facilitating the detachment of dead cells, exfoliation promotes more uniform cell turnover, leading to visibly radiant and even-toned skin.

The blackheads, also known as open comedones, are blockages in the pilosebaceous follicle. They form when sebum, naturally produced by the sebaceous glands, accumulates in the pore and mixes with dead cells from the stratum corneum. This mixture creates a slightly raised plug. Unlike closed comedones, the pore remains open, allowing the lipid-rich content to oxidize on contact with air, giving the blackhead its characteristic color.

Exfoliation helps prevent and reduce blackheads by acting on multiple levels. By promoting the removal of dead skin cells, it limits the hyperkeratinization responsible for pore blockage. It also contributes to maintaining clear follicular openings, facilitating sebum flow to the skin’s surface. Exfoliation is therefore particularly beneficial for oily, blemish-prone skin, although it benefits all skin types.

The stratum corneum, the outermost layer of the skin, serves a protective function and is part of the skin barrier. When it becomes excessively thick due to the accumulation of dead cells, this hyperkeratinization phenomenon can hinder the penetration of cosmetic actives. Indeed, skincare products applied to the skin’s surface then struggle to cross this barrier, which limits their bioavailability and, consequently, their efficacy. By promoting the shedding of corneocytes at the epidermal surface, exfoliation refines the stratum corneum and restores a more even skin surface.

Post-exfoliation skincare treatments are therefore more capable of penetrating the skin and delivering effective results.

The pigmentation spots result from an imbalance in melanogenesis, the biological process by which melanocytes produce melanin. Under the influence of various factors—such as UV rays, inflammation, or hormonal fluctuations—melanin production can become locally excessive and unevenly distributed. This pigment accumulation appears as brown, sometimes reddish or pinkish, spots, most often on sun-exposed areas, especially the face.

Exfoliation helps to gradually reduce these pigment irregularities. By removing melanin-laden cells from the surface of the epidermis, it accelerates cell turnover and promotes a more even complexion. Furthermore, by thinning the stratum corneum, exfoliation optimizes the penetration of pigmentation-targeting treatments, such as active ingredients that inhibit melanogenesis or modulate melanin transfer.

These effects of exfoliation on skin tone uniformity are notably supported by clinical data. A study conducted in India with 40 patients with melasma compared the efficacy of 50% glycolic acid peels and 80% lactic acid peels. Patients underwent four sessions at two-week intervals, with the severity of pigmentary lesions assessed using the MASI score. The results showed a significantly greater reduction in MASI in the glycolic acid group compared to the lactic acid group, with no notable difference in adverse effects (erythema or post-inflammatory hyperpigmentation transient).

These data demonstrate the value of exfoliating acids, particularly glycolic acid, for improving the appearance of brown spots.

• MILSTONE M. L. Epidermal desquamation. Journal of Dermatological Science (2004).

• RUSU A. & al. A comprehensive bibliographic review concerning the efficacy of organic acids for chemical peels treating acne vulgaris. Molecules (2023).

• RACHANA A. & al. 80% lactic acid peel versus 50% glycolic acid peel for melasma: A randomised clinical trial. Indian Journal of Dermatology (2025).