The effects of the peeling mask on blackheads.

Blackheads or open comedones are blemishes embedded beneath the epidermis. They are visible to the naked eye and feel rough to the touch. They are caused by the accumulation of excess sebum (hyperseborrhea) and the deposit of keratinocytes (hyperkeratinisation) which block the hair follicles. This mixture, upon contact with air, oxidises, and thus forms a small, hard black ball on the surface.

If left untreated, blackheads can rupture and release their contents outward, either spontaneously or when pressure is applied with fingers or a comedone extractor. They can also progress to an inflammatory stage and form red and painful acne spots. Blackheads appear more frequently on combination to oily skin types, particularly in areas rich in sebaceous glands: the nose, forehead and chin, but also the chest or décolletage, shoulders and back.

There are certain factors that promote the occurrence of blackheads:

• An improperly cleansed skin;

• An irritation of the skin (dysfunctional barrier function) stimulating the overproduction of sebum;

• The application of comedogenic skincare products such as coconut oil;

• Hormonal changes (puberty, menstruation, pregnancy, intake of certain pills, menopause);

• Pollution;

• Thefrequent and prolonged exposure to the sun.

To diminish the appearance of blackheads and/or prevent their occurrence, certain treatments are highly recommended, such as performing peeling masks once or twice a week.

The term 'peeling' refers to the act of peeling. In fact, it is aboutexfoliating the superficial layer of the epidermis to promote cellular renewal.

Peeling differs from scrubbing in its mode of action. Scrubbing is a mechanical exfoliation that removes dead cells from the epidermis through friction. Peeling is a chemical exfoliation that eliminates keratinocytes by breaking the ionic bonds, thus destabilising the horny layer and causing its gradual detachment.

Generally, a chemical peel involves substances known as AHA (alpha hydroxy acid), BHA (beta hydroxy acid) or PHA (poly hydroxy acid).

• The most common AHAs are theglycolic acidand thelactic acid. Glycolic acid, being smaller in size than lactic acid, penetrates deeper into the epidermis, hence its greater potential for irritation. For this reason, chemical peels based on lactic acid are generally recommended for the most sensitive skin types.

• The most common BHA in cosmetics is thesalicylic acid. Its antibacterial properties make it an active ingredient of choice for the chemical exfoliation of combination to oily skin with blemishes.

• With a larger molecular size than AHA and BHA, PHA penetrate less deeply into the epidermis and are more suitable for atopic skin and/or skin with cutaneous conditions. The three main PHAs used in cosmetics are the gluconolactone, an antioxidant that effectively combats inflammation; the galactose, which stimulates collagen production and the lactobionic acid known for its moisturising properties.