AnneLiese Smylie BSc1, Anil Kurian MD2, Benjamin Barankin MD, FRCPC3

1Faculty of Medicine, University of Alberta, Edmonton, AB,Canada
2Division of Dermatology & Cutaneous Sciences, Department of Medicine, University of Alberta, Edmonton, AB, Canada
3Toronto Dermatology Centre, Toronto, ON, Canada



Chemical exfoliation has been used for decades to reverse the signs of aging skin and provide a cosmetic benefit. Alpha Hydroxy Acids (AHAs) have been at the forefront in revolutionizing the skin care industry, particularly glycolic acid-based therapies. Daily low dose glycolic acid formulations have been proven safe and effective for at-home use and have become widely popular amongst consumers. Recently, a new product line containing either 5% Encapsulated Glycolic Acid (GA) or 10% GA with the Amphoteric System, has been added to the market. It offers options for those with sensitive skin to benefit from GA therapy, while also providing those familiar with GA regimens to further benefit their skin’s appearance.


  • The application of chemicals to the skin in the pursuit of aesthetic improvement can be traced back to ancient times.1 Alabaster, grape skins, sour milk, salt, and animal oils are just some examples of chemicals used four thousand years ago to rejuvenate the skin.1,2
  • The Romans rubbed the skins of fermented grapes on themselves to enhance their beauty, while Cleopatra allegedly would bathe in sour milk to have smoother skin.2 It would later be discovered that tartaric acid in grapes and lactic acid in sour milk, the chemicals responsible for skin enhancement, are both alpha hydroxy acids.1,2
  • The use of alpha hydroxy acids is now well established by dermatologists in products such as chemical peels,3 a form of skin resurfacing or exfoliation that benefits conditions such as acne and melasma, and improves overall skin tone.
  • Additionally, initial signs of aging skin begin to appear after the age of 28.4 The skin undergoes intrinsic changes which results in atrophy of particular skin components.4
  • Further, sun exposure, smoking and other environmental factors can greatly accelerate changes in the skin.4,5
  • Consequently, a variety of skin exfoliation technologies containing GA have been developed to reverse the various signs of aging skin, which can be broadly broken down into mechanical and chemical modalities.2,4
  • With any of these approaches an accurate assessment of an individual’s baseline skin condition is crucial for success of the treatment and preventing complications, such as hypertrophic scarring.6

Mechanical Exfoliation

  • Mechanical exfoliation uses physical or “mechanical” means to abrade the skin and achieve the desired effect.6,7
  • Microdermabrasion and dermabrasion are two examples of mechanical exfoliation and their difference lies in the depths to which they abrade the skin.6,7
  • Microdermabrasion is a non-surgical technique that uses abrasive substances, such as aluminum oxide crystals, to act at the outermost layer of the epidermis, or the stratum corneum.6,7
  • The ablation of the most superficial layer of the skin reveals the underlying healthy skin.6,7 It is best suited to patients with minimally photo-aged skin that are looking for cosmetic improvements to their skins texture and tone, with minimal inconvenience.6,7
  • Dermabrasion, a more aggressive form of resurfacing, acts at the level of the dermis.6 Since this mechanical exfoliation penetrates into the dermis, completely removing the epidermis, it promotes re-epithelialization and collagen remodeling.6
  • In turn, this technique, when performed by a qualified professional, leads to significant clinical improvements in skin architecture, although more recovery time is usually required.6
  • Dermabrasion can be used to improve a much wider range of skin conditions than microdermabrasion.6
  • Various scars, facial rhytides, tattoos, rhinophyma, and actinic keratosis can all be treated with dermabrasion.6

Chemical Exfoliation

  • Chemical exfoliation, such as chemical peels, abrade the skin at a desired depth to achieve a cosmetic effect.2,8-10
  • Chemical peels can be classified into three groups: superficial, medium and deep, based on the depth to which they penetrate the skin.2,8,9
  • The depth of peeling is dependent not only on the particular chemical used but also on the concentration at which it is used.8,9
  • The deeper the peel, the more discomfort and potential side effects may occur, and consequently, the greater the recovery time. However, deeper peels also provide better cosmetic results. For example, trichloroacetic acid (TCA; also sometimes referred to as bichloroacetic acid) can be used for deep peels, medium-deep peels, or superficial peels depending on the concentration at which it is used.8
  • By knowing the depth to which a chemical penetrates into the skin, dermatologists are better able to predict which skin abnormalities will benefit the most from a particular exfoliation.2
  • In order to achieve the best results, a chemical peel must extend as deep as the skin abnormality to be corrected.2

Superficial Peels

  • These peels penetrate into the epidermis and do not extend further than the dermal-epidermal interface.2,8,9
  • Typically, superficial peels are associated with a sensation of heat.8 Examples of superficial peels include GA, beta hydroxyl acids, tretinoin, low concentration TCA, and β-lipohydroxy acid.11
  • Skin dyschromias, actinic keratosis, active acne, and improvement of skin tone are the predominant clinical indications for superficial peels.9
  • Since superficial peels are minimally abrasive, they are suitable for all skin types.9

Medium-depth Chemical Peels

  • These peels penetrate through the epidermis and into the papillary dermis.2,8,9
  • A topical anaesthetic is sometimes required.8
  • Numerous solar lentigines, dyschromia and melasma, actinic keratoses, acne and altered skin texture are the main indications to perform a medium-depth chemical peel.9
  • TCA, GA, and augmented TCA (with GA, or Jessner solution) are the most common medium-depth agents.2

Deep Peels

  • These peels penetrate through the epidermis, papillary dermis and into the reticular dermis.2,8,9 As a result, they typically require general anesthesia.8
  • Deep peeling solutions are comprised of varying concentrations of phenol and croton oil.9
  • Fine and coarse wrinkling, actinic keratoses, acne scars, and dyschromia are the main indications for a deep chemical peel.9
  • These peels are the most effective in generating new collagen and deposition of glycosaminoglycans.2,9
  • Inflammation, common to all chemical resurfacing, stimulates the healing process.8
  • The amount of inflammation is correlated to the depth to which the chemicals penetrate into the skin.8
  • The inflammatory reaction is characterized by erythema, desquamation, and edema.11
  • With superficial peels, inflammation last 1-3 days, whereas with medium to deep peels, inflammation can last 5-10 days.11 These deeper peels can require longer periods of recovery time.2,11

Side Effects

  • Side effects of chemical peels include acneiform eruptions, postinflammatory hyperpigmentation, hypopigmentation, scarring, infection, and persistent erythema.2
  • Different ethnicities may not respond in a predictable manner with chemical peels.11 Therefore, a thorough individual history is quite important, with particular attention paid to instances of postinflammatory hyperpigmentation.11, 2
  • To minimize complications, it is important to select the most appropriate peel accurately for each patient, and it is critical that any kind of chemical peel be administered by a trained skin professional.
  • In general, the deeper a chemical peel penetrates the greater the risk of complications.8 However, the deeper a peel extends the greater the potential cosmetic benefit.8
  • In the care of a trained professional, the outcome with any chemical peel is mostly predictable, and ensures that patients receive the greatest cosmetic benefit possible with minimal chance of adverse reactions.2

Glycolic Acid

  • Alpha-hydroxy acids (AHA) are naturally occurring acids found in organic materials such as fruit, milk, and wine.12
  • Many of these acids are utilized in topical preparations to exfoliate the skin and yield a cosmetic benefit.13
  • In addition, these acids possess comedolytic effects when used at a particular pH and thus are beneficial in acne-prone patients.14
  • By gently removing the top layers of skin, other concurrent active ingredients will penetrate deeper and provide enhanced effects.
  • GA is an AHA originating from sugarcane, and is the most commonly used acid in AHA peels, due to its natural origin and ability to easily penetrate the skin.3
  • The use of GA peels on skin yields cosmetic as well as therapeutic benefits attributed to its antioxidant, anti-inflammatory and keratolytic effects.3
  • The depth to which the GA penetrates the skin is dependent on its concentration, pH, and amount of time left on the skin.
  • A lower pH and increasing concentrations of GA results in deeper exfoliation.3
  • Typically, GA peels are superficial in depth, resulting in very little recovery time for patients.3
  • A daily regimen of low-dose GA formulations has become widely popularized as a method of reducing signs of photo-aging and improving skin texture and tone.15
  • One particular study showed an improvement to general skin texture and a modest reduction in the signs of photo-aging in patients using a daily 5% GA solution compared to those using a placebo solution.15
  • A separate study showed that patients using a daily 8% GA solution experienced significant overall improvement in the severity of cutaneous photodamage after 22 weeks of use.16
  • In addition to daily low-dose GA formulations showing improvements to photodamaged skin, they also offer benefit to patients suffering from acne.14,17
  • Researchers have demonstrated the comedolytic benefits of this acid using a daily 10% GA formulation in patients with mild acne.14 One study showed that after 90 days, there was an improvement in acne severity in all patients who received the 10% GA solution (n=59), compared to the placebo group (n=60), with minimal adverse effects.14
  • Therefore, in patients with mild acne, a 10% GA solution could be considered as an alternative monotherapy to current popular regimens.14

Glycolic Renewal™

  • Given how minimally invasive and safe low-dose GA preparations are across all skin phototypes, numerous skin care products have been developed containing low doses of this acid for at-home use.3,17
  • As a result of the benefit they can provide in reducing signs of aging and cutaneous photodamage, low-dose GA preparations have become quite popular amongst consumers.3,17
  • Recently, two new formulations utilizing encapsulated GA at a concentration of 5% have entered the market as well as two formulations with GA at a concentration of 10%.
  • The new encapsulation delivery system allows the GA to better penetrate into the epidermis without irritation typical to AHA use.19
  • The 5% encapsulated GA formulation is for patients with sensitive skin, and those whose skin is treatment-naïve to GA. The 10% GA product is for those who have previously used GA therapies.
  • Independent research involving patients who applied the 5% GA encapsulated formulation twice daily for 2 weeks, followed by twice daily application of the glycolic renewal 10%.19 showed that after 28 days, there was a reduction in wrinkles by up to 72%, a visible reduction in total length of wrinkles by up to 68%, and a visible reduction in total area of wrinkles by up to 60%.19
  • After 56 days, skin analyzed on cross polarized images showed up to a 78% improvement in skin tone evenness, based on both clinician and patient evaluation.19 The glycolic renewal products are available as a cream and lotion in both 5% and 10% formulations, to suit different skin types and seasons.19
  • Patients with normal to dry skin are best suited to the smoothing cream.19 Patients with combination to oily skin are better suited to the smoothing lotion.19


The skin care industry underwent a dramatic transformation when AHAs were introduced in the early in the 1970s.18 Today, AHAs, such as GA, are widely used in cosmetic dermatology to reverse many signs of aging skin, and offer benefit to a wide array of skin diseases.3,18 GA peels have been researched for decades, and are proven to be a simple, effective, and evidence-based method of providing significant cosmetic and therapeutic benefits to the skin of appropriately selected patients.3,18 Continued innovation with GA skin care products has resulted in improved delivery systems, reduced adverse effects and better cosmetic benefits.3,18 NeoStrata’s two new formulations, the glycolic renewal cream and lotion, utilize encapsulated GA and the amphoteric system to provide patients of all skin types with the benefits of AHA therapy.


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  3. Sharad J. Clin Cosmet Investig Dermatol. 2013;6:281-288.
  4. Hirsch RJ, Dayan SH, Shah AR. Facial Plastic Surgery Clinics of North America. 2004;12:311-321.
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  16. Stiller MJ, Bartolone J, Stern R, et al. Arch Dermatol. 1996;132:631-636.
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  18. Robas-Macawile S. Updated June 11, 2011. Accessed 08/03, 2014.
  19. NeoStrata. NeoStrata Glycolic Renewal. 2014.