Editor’s note: Today’s anti-aging market is much broader than traditional wrinkle-reducing creams for middle-aged women. Men are now interested in anti-aging products; also, millennials, who are focused on early skin health maintenance.
Consumer mindsets diverge between well aging, i.e., embracing age as part of life experience; and demanding immediately perceivable effects—even turning to more invasive treatments, younger. Within the latter context, the present article discusses facial peels, to provide formulators anti-aging and other skin health insights from a professional spa product perspective.
Peels often are included in the treatment panels offered by aesthetic practices. They provide a wide variety of “aggressiveness” and, as such, can address several skin issues.
Peels have evolved a great deal since their initial use. The ancient Chinese used peels thousands of years ago, as did the ancient Egyptians (see Figure 1). One of today’s modern peel ingredients, lactic acid, an alpha hydroxy acid derived from sour milk, often was included in these very early peels in addition to a variety of other substances including herbs, scented oils and—in the case of the Egyptians—ground alabaster stone.
The modern era of chemical peels began in the late 1800s when physicians started experimenting with various chemicals, some very caustic and some less so, to improve facial aesthetics and skin problems such as acne or scars. Many of these chemicals are still used today in various concentrations.
After World War I, chemical peels were used to lessen disfigurations caused by facial shrapnel wounds. Thereafter, the Jessner Peel was developed in the 1950s and is still used in its original and modified formulas. Such modified Jessner Peels can vary a great deal in terms of the ingredients and percentages used; consequently, their effects also vary widely. A timeline of chemical peel development is shown in Figure 1.
Chemical peels have continuously been modified since the time of Jessner. Indeed, these post-modern peels are sometimes called “designer peels” or “hybrid peels” to indicate the wide range and mechanisms of their ingredients. Peel formulas have expanded to include antioxidants, derivatives of traditional ingredients, peptides, botanicals and other actives. Most of these designer peels conform to the modern consumer’s desire for excellent results with as little “down time” as possible.
Peel Depths and Ingredients
Peels are classified in many ways; by ingredient classes, by chemical groups, by conventional names such as the Jessner Peel, by peel depths and others. All of these types have their own specific advantages. Peel depths will be discussed here, and sample ingredients given for the various depths. It is important to consider that peel depths may change with various factors including concentration modifications, the addition of synergistic ingredients from one or several chemical classes, modification of pH, and other formulation changes. An impressive number of ingredient combinations and concentrations may be designed.
All peels work by generating “controlled” damage and a “controlled” inflammatory response. The practitioner’s responsibility is to effectively match the peel chosen to the patient so that the desired outcome occurs. Even superficial peels, via inflammatory mediators, will increase collagen formation over time due to the response to wounding.1 Although these initial changes may be initially experienced in the epidermis, cytokines and other chemical messengers will communicate the biochemical events to the dermis and stimulate collagen formation. Peel depth may be explained as follows.2
Very superficial peels: These involve the stratum corneum only and are usually combinations of low percentages of alpha hydroxy acids (AHAs). AHAs are good for exfoliating the surface linear layers of skin. Combining different AHAs, each of lower percentages, can potentiate the exfoliating effects while keeping the side effect profile quite low.
AHAs may be derived from botanical sources such as sugar cane for glycolic acid or may be chemically synthesized. Typical AHAs include glycolic, lactic, malic, tartaric and citric. These very superficial peels may also be combined with microdermabrasion or other very superficial resurfacing procedures. Low concentrations of glycolic acid are commonly used in peels. Glycolic acid is the smallest molecule of the AHAs and therefore has the best skin penetration.3
Superficial peels: Superficial peels do not penetrate the dermal-epidermal junction and their primary effects remain confined within the epidermis. These peels may be formulated with alpha hydroxy acids and/or beta hydroxy acids (BHAs). One of the best-known superficial peels is the Jessner Peel; the classic Jessner Peel contains 14% each of: resorcinol, lactic acid and salicylic acid in a base of ethanol.
All peels work by generating “controlled” damage and a “controlled” inflammatory response. The practitioner’s responsibility is to effectively match the peel chosen to the patient so that the desired outcome occurs.
Concentrations of glycolic acid from 20% to 70% may be used; notably, higher concentrations of glycolic acid require proper neutralization.4 It is best to use the manufacturer’s recommended neutralization solution since adding an acid to a base can generate heat, resulting in a thermal burn to skin. Baking soda plus water also is sometimes used to neutralize glycolic acid in some practices.5
Combinations of AHAs plus a BHA, such as salicylic acid, are excellent for acne; indeed, there are many reports of using Jessner Peels to address acne.6 As noted, since this peel was first developed, there have been numerous modified Jessner Peels and, as such, one must know the ingredients and their percentages to understand the exact formulation—to only refer to a “modified Jessner Peel” is insufficient information.
Medium depth peels: These peels penetrate the DEJ into the papillary dermis but do not enter the deeper reticular dermis. Trichloroacetic acid (TCA) peels are well-known medium depth peels.
Deep peels: Deep peels extending into the reticular dermis are now seldom used due to their potential risk for complications. Such phenol peels are used in higher concentration ranges, although lower concentrations of phenol may be combined with other ingredients for medium depth peels. Deep phenol peels are painful and require anesthesia.7 Further, if hair bulbs are inadvertently removed, this also removes the last and deepest layer of stem cells and can result in permanent scarring.
Complications from Chemical Peels
Clearly, chemical peels can be invasive treatments. As such, immediate or delayed complications can occur. These may include mild effects such as burning or itching, which is often the expected occurrence; accidental exposures, such as getting peel solution in the eyes; infections; scarring; herpetic eruptions; hypopigmentation; or other delayed effects such as post-inflammatory hyperpigmentation.8, 9 The majority of these are best avoided by proper and cautious patient selection and appropriate peel technique and selection.
Designer or Hybrid Peels
It is worth mentioning many combination peels are also now in use. These contain a variety of ingredients in varying concentrations. In addition to the common ingredients mentioned, these newer designer peels may also include antioxidants, peptides and botanical ingredients.
Combinations of AHAs plus a BHA, such as salicylic acid, are excellent for acne; indeed, there are many reports of using Jessner Peels to address acne.
Case Studies: Acne and Pigmentation
Finally, many skin issues can benefit from peels; especially hyperpigmentation, acne and aging. Some patients also seek chemical peels for acne scarring or general complexion rejuvenation. Following is an example; in Figures 2 and 3 (see below), this Fitzpatrick IV patient with acne was treated using a designer peel including:
Prep solution: ethanol as the defatting agent and a botanical antioxidant/anti-inflammatory;
Peel solution: modified Jessner Peel solution containing both AHAs and a BHA; and
Booster: keratolytic ingredients, antioxidant, lightener, anti-inflammatory, collagen booster and elastin synthesizer.
The observed improvements occurred after only one peel. Typically, a series of peels is planned; in this case, four to six weeks apart—which would be expected to give further improvements. Notice the improvement in pigmentary irregularities and skin texture.