Peel solutions may contain alpha hydroxy acids (glycolic or lactic acid), beta hydroxy acid (salicylic acid), tricholoracetic acid (TCA), or phenol as the peeling agent. Each of these is categorized by the percentage of its concentration and the resulting depth of the peel that takes place on the skin. Fine lines and wrinkles, skin discolorations, reduction in the appearance of skin discolorations and scars, along with overall improvement in skin texture and subtle rebuilding of the skin’s collagen are all possible outcomes of chemical peels.
There are definite drawbacks to consider, but what these may be is largely dependent on the depth of peel. The risk of complication is directly related to the amount of benefit desired. Superficial peels (almost always either glycolic acid or lactic acid) have little to no associated risks, but also produce less dramatic results. Low-concentration glycolic acid and salicylic acid peels can have rare side effects, and prolonged redness, swelling, and increased skin sensitivity do occur.
When more significant results are desired, the complications increase proportionately. Skin discoloration can occur in medium and deeper peels (called hypo – or hyperpigmentation) where the skin becomes either darker or lighter in certain areas. Many more complications and scars are recorded from TCA peeling than from phenol, perhaps because of the care with which phenol peels must be performed, and the implied safety of TCA (Source: eMedicine Journal, February 14, 2002, volume 3, number 2).
Chemical peels are performed by the application of the specific solution that peels away the skin’s top layers, either on the entire face or on specific areas. Often, several shallow to medium-depth peels can achieve results similar to one deep-peel treatment, with less postprocedure risk and a shorter recovery time.
Alpha hydroxy acids (AHA) use glycolic acid as the chemical ingredient. Various concentrations can be applied, but most commonly 30% to 70% concentrations are used. Lower-concentration peels can be used by an aesthetician and are a popular spa procedure. Again, the lower the concentration of AHA, the less impressive the results will be.
Low-concentration AHA peels are effective in improving skin texture; they cause some collagen and elastin rebuilding, somewhat reduce the appearance of acne scarring, and reduce the appearance of skin discolorations. The effects are all temporary and subsequent treatments, spaced anywhere between six weeks and two months apart, are required (Source: American Journal of Clinical Dermatology, March-April 2000, pages 81-88).
AHA peels are not medical procedures and as a result are not regulated by the FDA. A physician usually performs higher-concentration peels, but this is not always the case. In lower-concentration peels, often performed by aestheticians, repeated treatments are necessary to achieve and maintain the results seen immediately after the peel is performed.
Beta hydroxy acid (BHA) or salicylic acid peels are not as popular as AHA peels, yet they are equally as effective and have specific advantages for some skin types. A solution of salicylic acid can work in a way that is similar to a glycolic acid peel, but irritation is much reduced. Salicylic acid is a compound closely related to aspirin (acetylsalicylic acid), and it retains its aspirin-like anti-inflammatory properties. A deep BHA peel can be superior for many skin types because the irritation and inflammation are kept to a minimum due to the analgesic action of the BHA compound. Salicylic acid is also lipid soluble, which means it is a good peeling agent for blemish-prone skin with blackheads. The most common concentrations used today are 20% to 30% (Source: Dermatologic Surgery, March 1998, pages 325-328).
Trichloroacetic acid (TCA) peels in concentrations of 10% to 35% have been used for many years and are considered effective and safe (Source: Dermatologic Clinics, July 2001, pages 413-425). TCA can be used for peeling the face, neck, hands, and other exposed areas of the body. It has less bleaching effect than phenol (see the next paragraph) and is excellent for “spot” peeling of specific areas. It can be used for medium or light peeling, depending on the concentration and method of application. TCA peels are best for fine lines but are minimally effective on deeper wrinkling (Source: eMedicine Journal, December 5, 2001, volume 2, number 12). However, at higher concentrations, such as 50% and above, TCA has a tendency to scar and is less manageable than other agents used for superficial peels.
Phenol is sometimes, though rarely, used for full-face peeling when sun damage or wrinkling is severe. It can also be used to treat limited areas of the face, such as deep wrinkles around the mouth, but it may permanently bleach the skin, leaving a line of demarcation between the treated and untreated areas that must be covered with makeup. “Although phenol produces the most remarkable resolution of actinic damage and wrinkling among the various [chemical peels] … it also possesses some of the more significant [serious side
effects]. Many have abandoned phenol in favor of other agents or laser resurfacing__________
Hypopigmentation may occur in all skin types, noticeably lightening patients with darker skin and making lighter-skinned patients appear waxy or pale. A clear line of demarcation may be present between treated and untreated skin” (Source: eMedicine Journal, July 20, 2001, volume 2, number 7). Given the positive results that can be achieved with other resurfacing procedures and the extreme risks associated with phenol, this method is actively discouraged and rarely used.
Buffered phenol offers yet another option for severely sun-damaged skin. One such formula uses olive oil, among other ingredients, to diminish the strength of the phenol solution. Another, slightly milder formula uses glycerin. A buffered phenol peel may be more comfortable for patients, and the skin heals faster than with a standard phenol peel, but it is still a risky procedure that can depigment the skin (Source: Facial Plastic Surgery Clinics of North America, August 2001, pages 351-376).