Stretch marks: chemical peeling

Action Mechanism

Chemical peeling is an accelerated form of exfoliation that occurs through the use of chemicals.

There are light peels and deep peels. A superficial peeling accelerates the natural exfoliation of the stratum corneum, while a deep peeling creates necrosis and inflammation in the epidermis, in the papillary dermis or in the reticular dermis, with the fundamental aim of provoking the deep detachment of the atrophic skin in the treated areas, for then favor the neosynthesis of skin tissue through the stimulation of fibroblasts. Chemical peeling creates obvious changes in the skin through three mechanisms of action:

stimulation of cell turnover by removing dead cells from the stratum corneum;
elimination of damaged and degenerated epidermal cells, which will be replaced by normal epidermal cells. This result will be particularly evident in the treatment of actinic keratoses and abnormal pigmentations;
introduction of an inflammatory reaction and activation of inflammation mediators (a mechanism still little known) that activates the production of new collagen and glycosaminoglycan fibers (revitalizing mechanisms of the dermis).

Glycolic acid

An example of a molecule capable of performing this function is glycolic acid : derived from sugar cane, it is the smallest molecule of alpha-hydroxy acids. Used in the dermatological field, it succeeds in penetrating the deepest states of the epidermis, stimulating cell renewal and the production of elastin and collagen, and at the same time it acts as an exfoliant, freeing the surface of the dermis from impurities and dead cells. Thanks to this double action, glycolic acid gradually rebalances the level between the normal skin surface and that of the stretched area 1, 2, 3. The concentration of use of the acid (which can vary from 20 to 70%), and the application time in which it is left to act on the skin, depends on the depth of the stretch mark.

dihydroxyacetone

An alternative to traditional anti-stretch mark treatments is the application of cosmetics containing dihydroxyacetone (DHA), a small synthetic molecule that, applied to the skin, reacts with the amino acids of keratin to form complexes colored from yellow to brown (Maillard reaction), allowing to mask the color of both older (mother-of-pearl) and newer (pink-red) stretch marks. The covering effect lasts for 4 or 5 days.

Tab 1. Types of products for the treatment of striae distensae and mechanism of action
Product	indication	Action mechanism
Tretinoin	healing	Stimulation of fibroblasts
Trofolastina	healing	Active ingredient contained in centella asiatica extract: stimulates fibroblast proliferation
Hyaluronic acid	Price quotation	Improves the mechanical characteristics of the skin
Massage with emollients	Price quotation	Dual action: circulation stimulation through massage and moisturizing action of the oils
Glycolic acid and other chemical exfoliants	healing	Glycolic acid stimulates the production of collagen and increases the proliferation of fibroblasts in vivo and in vitro

Technical analysis of some products against stretch marks on the market

Stretch Marks-Intensive Stretching Cream Special Stretch Marks-Pregnancy and Slimming Diets Oil 9 Months Rilastil Stretch Marks Cream Stretch Mark Tone-Up Bionike Defense Body Stretch Marks Phytolastil Soluté Stretch Mark Control Stretch Mark Butter Stretch Mark Cream Intensive Stretch Mark Cream Stretch Mark Cream

1 US patent. Method of applying alpha hydroxy acids for treating striae distensae. Available from //www.freepatentsonline.com/544091.html (Accessed 29/12/2007)

2 Ash K, Lord J, Zukowski M, McDaniel DH. Comparison of topical therapy for striae alba (20% glycolic acid / 0.05% tretinoin versus 20% glycolic acid / 10% l-ascorbic acid). Dermatol Surg 1998; 24: 849–56.

3 Kim SJ, Park JH, Kim DH, et al . Increased in vivo collagen synthesis and in vitro cell proliferative effect of glycolic acid. Dermatol Surg 1998; 24: 1054–8