Chemical Peels

The science of peels

Chemical skin peels are one of the most recognised forms of defence against the myriad effects of ageing upon the skin. With the removal of old skin cells, new cell regeneration is promoted and the visible effects of ageing from sun damage to acne are ameliorated. The skin is left smoother and softer with the appearance of pore size, pigmentation, fine lines, age spots and even superficial scars improved. Professional peels – that is, peels conducted by a trained professional in the clinic setting – are of a greater concentration than those permitted at home and as such are more effective.

Superficial peels will act on the surface or outer layer of the skin, leading to effective chemical exfoliation, while deeper-performing peels have the ability to penetrate further into the skin and therefore achieve a more stimulating effect as well as the exfoliation described above.

The mechanism of the peel is key. The skin’s outermost layer, the epidermis, consists of four strata, or levels. New skin cells form in the deepest layer, the stratum basale. Through the process known as keratinisation, these cells migrate up through successive layers from the stratum basale to the stratum corneum, the outermost layer. We know that the cells of the stratum corneum shed at the rate of about one cell layer per day but with an increase in age, that process of shedding slows down, and flat, dry cells accumulate on the skin’s surface, giving a dull appearance to the skin and obstructing any effective application of products.

In the stratum basale, melanocyte cells produce melanin, the pigment responsible for giving the skin its colour and for its protection from UV rays and their damage. As melanin accumulates in structures called melanosomes, it darkens and obscures the melanosomes’ internal structures, which leads to the transferral of the melanosome to the keratinocyte as it makes the migration from the stratum basale up to the stratum corneum. Melanin comprises two major components: the brown-black eumelanin and the yellow-red pheomelanin. The brownish colour continues to migrate to the skin surface intracellularly, hence the colour visible on the surface in tanned skin, in freckles or age spots, or simply pigmentation. In skin that has been photodamaged by UV rays, the distribution of the melanocytes is uneven, leading to brown spots, from freckles (ephelides), to age-related “liver” spots (solar lentigines), and melasma, the pigmentation pattern associated with hormonal changes such as during pregnancy. In cases of severe skin damage from UV rays, melanin can even be seen to appear below the epidermis, in the dermis.

Peels will help to address these issues, alongside tackling the wrinkles and lines caused by decreased collagen, decreased elastin and glycosaminoglycans (GAGs), which hold moisture in the dermis, and from the flattening of the rete processes, the epidermal epithelial extensions which provide increased surface area for nutrient exchange between the dermis and epidermis.

Skin biopsies have long documented that chemical peels effectively thin the stratum corneum, thicken and plump the epidermis, and also increase dermal collagen production. It is often advised that anyone who undergoes a professional peel supports its effects with a routine at home to receive even greater benefits and maintain the results. The key caveat of peels is that the improvement can be dramatic but is not permanent, hence the usual professional recommendation for a series of peels rather than simply one single attempt.

Further reading and research

Cochrane Database Syst. Rev. 2005 Jan 25; (1): CD001782
Interventions for photodamaged skin
M Samuel, RC Brooke, S Hollis, CE Griffiths

Semin. Plast. Surg. 2016 Aug; 30(3): 129-33
Noninvasive Facial Rejuvenation. Part 1: Patient-Directed
SJ Commander, D Chang, A Fakhro, MG Nigro, EI Lee

Semin. Plast. Surg. 2016 Aug; 30(3): 143-50
Noninvasive Facial Rejuvenation. Part 3: Physician-Directed-Lasers, Chemical Peels, and Other Noninvasive Modalities
JD Meaike, N Agrawal, D Chang, EI Lee, MG Nigro

Facial Plast. Surg. 2013 Jun; 29(3): 154-60
Innovations in minimally invasive facial treatments
JR Jurado, LF Lima, IP Olivetti, HH Arroyo, IH de Oliveira

Facial Plast. Surg. Clin. North Am. 2001 May; 9(2): 239-55, viii
Chemical peels
GD Monheit, MA Chastain