Superficial Chemical Peels
Tuesday, June 07, 2005
Superficial chemical peeling is indeed a dermatologic art. It is
the skillful use of acidic substances to carefully remove the
stratum corneum and superficial epidermis to achieve an improvement
in the appearance of the skin. The improvement may be in skin
texture and/or skin pigmentation. The goal of this commentary is to
provide a basic outline for the formulation and administration of
superficial chemical peels.
Superficial chemical peeling involves the use of mild acids to
obtain a variety of desired results based on the patient's
expectations and the physician's therapeutic objectives. The
desired goal may be simply to induce exfoliation of corneocytes
that have failed to desquamate, resulting in smoother application
of facial foundation. In this case, a mild acid with short contact
time would be in order.
Superficial chemical peels of this type can also be used to
enhance penetration of other dermatologic agents, such as
hydroquinone for pigment-lightening purposes or retinoids for
Superficial chemical peeling involves the use of mild acids to
remove surface corneocytes that make up the stratum corneum.
Chemical dissolution of bonds at various levels of the stratum
corneum and epidermis determines the depth of the peel. By
definition, superficial chemical peels do not enter the dermis or
the lower layers of the epidermis. The two major acids that are
used for this purpose are glycolic acid and salicylic acid.
Glycolic acid is a water-soluble alphahydroxy acid of small
molecular weight that rapidly penetrates into the skin. It is
obtained from fermented sugar and as such is known as a fruit acid.
It can be both buffered and neutralized to limit its penetration
into the skin. I prefer to use undiluted, unbuffered peeling
solutions, as they are easier to formulate and more predictable in
their effect on skin.
Salicylic acid is commonly referred to as a betahydroxy acid. It
is a phenolic oil soluble compound with a rich dermatologic
history. Salicylic acid is a potent keratolytic that is able to
penetrate into the milieu of the pore, but it self-neutralizes by
crystallizing on the skin surface. Thus, it provides a nice
contrast to glycolic acid in its therapeutic effects. It can be
used as a peel for patients with acne, due to its ability to loosen
comedones, and for patients with sensitive skin, due to its
anti-inflammatory and self-neutralizing qualities.
A more aggressive superficial chemical peel can be achieved
through a combination of salicylic acid, lactic acid, resorcinol,
and ethyl alcohol. This solution is known as Jessner's solution and
is sometimes used to enhance the penetration of 25-35%
trichloroacetic acid to achieve medium-depth peeling.
Superficial peels can be easily self-formulated by the
Glycolic acid can be purchased from chemical supply houses as a
70% saturated solution. This solution can be used directly on the
skin for an aggressive superficial peel or diluted with water. I
prefer to dilute glycolic acid to concentrations of 20%, 30%, 40%,
50%, and 60%. These dilutions can be used to titrate the desired
depth of peeling for each patient:
- Glycolic acid 20% to 30% provides a mild exfoliation for the
patient with virgin skin. Patients who are using high-potency
retinoids, such as tazarotene, will obtain a more aggressive
- Glycolic acid 40% to 50% can be used as a step-up peel for
patients who began their treatment with 20% to 30% glycolic acid 3
- Glycolic acid 60% to 70% is an excellent treatment for the
patient wishing to improve skin dyspigmentation or fine wrinkling.
This type of peel will also enhance penetration of hydroquinone and
retinoids to speed antiaging therapy.
Salicylic acid is purchased as a white crystalline powder. The
powder must be dissolved in benzyl or ethyl alcohol due to its oil
solubility. I prefer benzyl alcohol, as it is not quite as fragrant
or volatile as ethyl alcohol. I dilute my salicylic acid peels to
10%, 20%, 30%, 40%, and 50%. Peel strengths of 10% to 20% are
solutions, but 30%, 40%, and 50% strengths are shake lotions, since
somewhere between 20% to 30% salicylic acid becomes a saturated
- Salicylic acid peels of 10% to 20% are excellent for acne
patients with dry skin, whereas salicylic acid peels of 30% to 40%
may be used in oily complected acne patients.
- 30% salicylic acid is probably the maximum strength recommended
for uncontrolled rosacea patients.
- Salicylic acid 40% to 50% may be used in the patient who wishes
more aggressive peeling.
In general, salicylic acid does not produce as deep a peel as a
similar concentration of glycolic acid.
In addition to self-formulating peel products, several
commercial skin peels are available. These commercially marketed
peels use buffers and other pH adjusters to decrease peel potency
and the resulting erythema.
The equipment required to administer a superficial salicylic or
glycolic acid peel is minimal. The peel solution should be
dispensed from a dark glass bottle into a small glass. I prefer to
use a shot glass. Approximately 2 cc is enough to cover the entire
The peel solution is best applied with a rectal swab dipped into
the glass and rapidly rubbed over the face, being careful not to
drip the peel solution. I prefer to put 2 or 3 coats over the
patient's face, inquiring as to the degree of discomfort.
When the patient reaches a pain level of 4 or 5 on a 10-point
scale, I neutralize with ice-cold water in a stainless steel bowl
and 2 disposable wash clothes. The skin is completely rinsed at
least 3 times, taking care to thoroughly remove the acid from the
corners of the nose and mouth.
The face is then patted dry and a bland moisturizing cream
applied, if the patient desires.
Careful patient selection is the key to the success of any peel.
Both salicylic and glycolic acid can be used without difficulty in
Caucasian patients, but patients of color should be peeled with
caution. Low concentrations of glycolic and salicylic acid should
be used to prevent postinflammatory hyperpigmentation. When in
doubt, begin with a salicylic acid peel in darker skin colors to
It is also important to determine the state of the skin that is
undergoing superficial chemical peeling. Patients who use
retinoids, undergo frequent facials or microdermabrasion, engage in
salon laser procedures, or use waxing as a method of hair removal
may experience unpredictable deeper peel penetration due to loss of
the stratum corneum. Obtaining a cosmetic procedure history is
important to obtaining reliable superficial peel results.
Superficial chemical peeling is an important part of the
dermatologic armamentarium. These peeling techniques are some of
the easiest to master, as the depth of penetration is limited to
the stratum corneum and the superficial viable epidermis. Glycolic
and salicylic acid peels in a variety of strengths can be
formulated in the office to customize the peel for the specific
patient's needs. Superficial peels can be used to improve skin
texture through exfoliation and may enhance the penetration of
antiaging compounds, improve dyspigmentation, and decrease fine