Exfoliation

A surface that is already renewing itself

On the surface of the epidermis, the stratum corneum is made up of cells that have become corneocytes, surrounded by lipids. It slows down water loss and helps protect the skin. Even if these cells are said to be dead, they therefore have a function. Their gradual elimination, called desquamation, occurs naturally: exfoliation accompanies or accentuates this detachment, it does not replace an absent mechanism.

When cells remain more closely linked together, the surface may appear rougher or less regular. By facilitating their separation, an exfoliator can improve the feel and appearance of the complexion. The scrub exerts a mechanical action; rather, acids modify cell cohesion. Neither removes “toxins” hidden under the skin, and a stripping sensation does not provide reliable information on the benefit obtained.

AHA: acting on the texture

The most common AHAs are glycolic and lactic acids. They promote surface exfoliation and are used in treatments intended for skin texture, certain complexion irregularities and superficial signs of aging. This explains their interest when the skin appears rough or dull. Their effect, however, is not limited to a promise of new skin: the changes remain dependent on the formula, the duration of use and the initial problem.

The percentage displayed does not, on its own, allow products to be classified by power. The pH determines in particular the proportion of acid in its non-ionized form, which influences its passage into the skin. A study on glycolic acid thus compared several concentrations and several pHs, with different effects. Two 5% formulas can therefore behave differently; increasing the number on the bottle is not a guarantee of better results.

BHA: the benefit for clogged pores

Salicylic acid, generally presented as a BHA in cosmetics, has an affinity for lipid environments. It can act in the sebum-rich environment of the follicle and facilitate the detachment of cells that contribute to its obstruction. This action explains its benefit on comedones, including blackheads. It does not mean that it sucks the pores or makes them disappear: it helps to limit what clogs them.

Its action is often described as keratolytic, but the term desmolytic describes more precisely the separation of cells by an action on their junctions, rather than a dissolution of all their keratin. In common acne treatments, its effect on blackheads remains moderate. Persistent inflammatory spots or acne that leaves scars therefore require appropriate treatment, rather than a succession of increasingly strong exfoliating products.

PHA: another possibility for tolerance

PHAs carry several hydroxyl groups and notably include gluconolactone. Their properties make it possible to formulate exfoliating treatments with a moisturizing benefit and a profile that is often better tolerated than certain classic AHAs. They can thus provide an avenue when they easily cause discomfort. This remains a formulation trend: perfume, other active ingredients and frequency of use also count, and already irritated skin does not need an additional acid, even one deemed mild.

Why Doing More Can Get Less Results

Excessive exfoliation can disrupt the skin barrier. The skin then becomes drier, uncomfortable or reactive, which causes the improvement initially sought to be lost. In people prone to pigment marks, especially on dark skin, the irritation can also leave spots. Trying to erase an irregularity by rubbing harder can therefore end up creating a new one; tolerance is part of the effectiveness of care.

Finally, we must distinguish surface maintenance from deeper treatment. A cosmetic exfoliator can improve texture and some marks, but it will not reconstruct a hollow scar or erase a deep wrinkle. Professional peels pursue other objectives with different products and monitoring. Reproducing their intensity at home exposes you to burns and scars, without offering the same mastery of the gesture.