Professor Tony Chu (President of the Acne & Rosacea Association, Previous Lecturer and Lead Consultant Dermatologist at Imperial London, and Professor of Dermatological Oncology) explains how different chemical peel ingredients can effectively treat common facial skin concerns by utilising new technology, so they are much more than exfoliating devices.

Chemical peels have made somewhat of a comeback in the past few years. There used to be more concern amongst practitioners about the effects of harsh ingredients in the peels, leading many to err on the side of caution. Around the same time, a variety of lasers started to come on to the market and peels were seen as less favourable. 

However, more recently, rather than being predominantly utilised for their exfoliating properties and influence on collagen matrix turnover, peels are being used to achieve significant results in common skin concerns.

There are many chemical agents available for skin peeling due to the advent of new ‘carrier’ systems, which can vary their impact from exfoliators to deep skin re-modellers, through to treatments for acne, rosacea, lines and wrinkles, pigmentation, and stretch marks.1,2,3,4,5 Used properly, I believe they can have substantial effects comparable to lasers and radiofrequency, and are far less likely to cause post-inflammatory hyperpigmentation (PIH).

This article discusses the different types of peeling agents and the results that can be achieved.

Treating the skin with peeling agents

The newly developed carrier solutions take the acids and associated treatment ingredients (protected from degradation by the acid by the carrier solution) across the stratum corneum and deep into the skin before being released to target specific skin concerns.

It is recommended all peels are used in conjunction with creams, (pre, post and in between peel treatments), which contain the same ingredients as those held in the peels. The peels will therefore boost activity of the creams, but also will minimise post procedural risk of PIH or excessive erythema.1,2,3,4,5

Below are some case study examples of multiple skin conditions that patients may present with and the appropriate peel treatments:

Case study: Patient A
→ Sun damage
→ Dark and puffy under eye
Reddening central area prone to rosacea
→ Spots and acne

Patient A has sun damage on the forehead, is prone to reddening and has some intermittent or permanent redness/vascularity in the central portion of the face. She also has recurrent outbreaks of spots around the chin and has dark and puffy areas under the eye – a delicate area of skin that needs a different approach.

Mosaic peeling is the new buzz phrase for selecting the most appropriate peel for each area utilising specific solutions best suited to each of the above indications, rather than a ‘cocktail’ peel approach of multiple acids applied to all areas or utilising a generic single acid such as glycolic acid.

Both those offerings are a ‘one size fits all’ approach; its lazy technique and will deliver poorer outcomes and increase the risk of complications. 

Glycolic acid is a general-purpose acid, it’s not lipophilic, and I believe other acids have better properties for specific skin issues, such as above.

One might argue, if one had various skin issues in different areas of the face, that a ‘cocktail’ peel, i.e., a peel with multiple acid or peeling ingredients, may be ideal; but each acid in the cocktail will be applied to all areas of the face and some may have a negative effect on some of the skin issues mentioned, while being positive in others. The ‘cocktail’ combination can cause increased pigmentation on the forehead as well as exacerbating the central area and increasing erythema and redness.

The diagram above represents a preferred choice of peels for Patient A.

Please note that this is for a patient whereby we have assessed them for risk issues, such as skin ethnicity, dehydration and trans epidermal water loss (TEWL) issues and found them to be low risk. 

40% mandelic acid is better for 
erythema control, 30% salicylic better for oil reduction, Jessner’s (14% resorcinol, 20% lactic acid and 15% salicylic acid), is better for sun damage. Glycolic would not be my choice for any of these.9,10 However, in darker more reactive skin types one might use mandelic acid instead of the Jessner’s. In either case, one would look to diminish complication risk utilising serums and creams which may reduce inflammatory issues such as hyperpigmentation or damage to vascular tissues. Also, the creams synergise with the peels to achieve the desired outcome and the creams deliver more than 50% of the result.

The unique feature of the carrier solutions is that the salicylic has three antibacterials and oil slowing ingredients also incorporated in the carrier matrix, which is delivered into the blocked hair follicle ducts. This peel is medically licensed for the treatment of comedogenic and inflammatory acne and resistant acne where in conjunction with the medically licensed creams containing the same antibacterials, anti-inflammatory and oil supressing ingredients resolved the symptoms of over 80% of GP referred resistant acne patients (defined as not resolved within 12 months) referred to the five teaching hospitals.

The mandelic is transported by the carrier into the dermis where it is released and activated and has a vasoconstrictive effect delivering improved vascular integrity, while the anti-inflammatories found in the rosacea creams are delivered with the mandelic to help control diffuse redness and increase flushing resistance, while also restricting VEGF from triggering excessive new capillary production. This peel is licensed for the treatment of vascular sub type 1 rosacea.

The Jessner’s peel also uses carrier technology to release anti- inflammatories into the upper epidermis to minimise erythema while the lactic acid and resorcinol are delivered predominantly to the area either side of the dermal epidermal junction to act on slowing melanogenesis. A form of resorcinol and other ingredients are provided in the creams to continue to normalise melanin production between treatments.

This mosaic approach is slightly more complex and needs a little bit more planning, but it will be far more attractive. The unused peel solution can be resealed with a reversible cap, and the remaining solution can be used on the second and third peel in the course of treatment, 2 to 4 weeks apart.

Mandelic acid 40% is typically a 10-minute exposure where as Jessners and Salicylic are both five minutes exposure and then the salicylate powder that forms (deactivated salicylic acid) is just removed. In the case of the Jessner’s, the lactic acid and resorcinol component is left in the skin to continue to work on the excess melanin production. This is termed extended exposure, but nothing is left on the surface of the skin.

So, at time zero the mandelic is applied to the central area of the face and at minute 5 the Jessner’s and 30% salicylic acid are applied to the forehead and lower face respectfully. At minute 10 all three are removed with a remover wipe or saline dampened cotton pads. The mandelic can either be removed or neutralised.

Although you may see many patients with the exact same skin problems, it is not possible to treat everyone with the same solution. The patient’s skin sensitivity, Fitzpatrick skin type, ethnicity, and the severity of photo damage and wrinkles, should all be taken into consideration.

The choice of agent will also vary depending on whether the patient has good skin moisture levels; for example, a high rate of TEWL (trans epidermal water loss) coupled with low hydration may indicate poor lipid density, and this may lead to a higher sensitivity to the remodelling agent and increase risk of adverse events such as erythema and PIH.

In this situation, I may revert to using a sequence of mandelic acid peels. The results may take longer to achieve but one would be mitigating for increased PIH risks.

Skin considerations

As mentioned, certain aspects should be taken into consideration before using any chemical peel.


Patients with mixed race background, who, for example, have a Celtic mother and an Arab father, where the patient may be a Fitzpatrick type 1, 2, 3 or 4,are traditionally assessed and treated as the darker parent would have been regardless of their Fitzpatrick type. This is because of concern about the level of inflammation the peel may cause and the risk of post treatment pigmentation increasing.

However, there is good data to suggest this may not be the most appropriate course of action.

Nabil Fanous defined that facial feature were more important than skin colour in determining PIH risk in mixed race clients. In simple terms, PIH risk is based on which parent the patient looked most like, skin colour supports the decision in choosing the correct protocol, but facial features take precedence in mixed race in determining PIH risk.7

For example, Celtic skin has high erythema sensitivity, whereas Arab skin has a high PIH risk. The offspring and patient with this mixed ethnic background may have the same Fitzpatrick skin type as a southern European; but the client would be treated differently, and the choice would be based on facial features not just Fitzpatrick type. If their features looked like the Celtic parent, then their PIH risk would be lower.

Ultimately, one size does not fit all. You need to ensure you do not cause longterm damage when treating the variousskin types with peels, as you would with lasers.

Below is a useful table from the Fanous study.

Fitzpatrick skin type

The Fitzpatrick classification categorises skin type according to its reactivity to the sun without UV protection rather than the degree of photo-damage. This classification helps identify patients who have a propensity for photo-damage. This relates to their likely risk level and response when exposed to skin challenging procedures.11

For facial chemical peels, this classification can also be used to define the risk of pigmentary changes (e.g., dyschromia, post inflammatory hyper pigmentation, permanent hypo pigmentation) and erythema when using resurfacing procedures.

Glogau scale

The Glogau scale of photo-ageing consists of four age-range levels where each level is defined by describing how a typical person’s skin would appear in that age range and what visible symptoms, they would typically manifest.

Depending on the level of ageing, the depth and degree of treatment to the skin may need to be modified.

More challenging skin concerns would traditionally need more of the same agent and possibly for a longer exposure time; this would result in more trauma. An alternative approach is to expose the patient’s skin to either a lower level of treatment and/or a shorter exposure time but to spread out the treatments over five to eight sessions instead of the usual four. So, it may be necessary to offer a different number of treatments, where the exposure time can be modified, and the results will become prominent over a longer time.

Important considerations

If patients present with a poor skin condition, such as low hydration, TEWL, pigmentation issues and damaged blood vessels, then consider no peel, but use creams for boosting skin structure, repair processes, priming and preparation, regardless of skin type. Then, an appropriate sequence of peels may be considered, interspersed with creams and serums to boost their response but also to limit complication development, such as pigmentation increase.

Peels need water to move through the skin, therefore, skin with poor hydration is more likely to react to the acid component of the peel (hydrogen ions) and experience localised damage to the surface, is more irritating and more likely to lead to complications. This is because poor hydration causes less mobility for the hydrogenions. (Theoretical Chemistry/Acids and Bases/Aqueous Solutions/The Hydronium Ion – Chemistry)

The periorbital skin is much thinner than the rest of the face; hence this needs to be taken into consideration. The type of agent used can be similar, but the strength and surface activity need to be lower. Phenols and high strength TCAs or pyruvic acid would not be appropriate. In my opinion, it is better to use lighter concentrations and add more layers. The number of layers used would vary depending on the patient’s skin type and sensitivity.

Length of peel time

Due to the ability to transport remodelling agents into the skin using specialised patented carrier technology1, 2, 3, 4, this can reduce surface trauma normally seen with traditional peel solutions by up to 50%. Exposure time is set prior to application and the peel is neutralised or removed regardless of visible erythema or frosting.

However, the visible symptoms of the peel and patient response in terms of pain are still taken heed of, if trauma becomes apparent.

Exposure for mandelic is traditionally ten minutes, for pyruvic it is one to three and then if considered appropriate a second layer for up to a further two minutes, depending on layers and patient response, and for trichloroacetic acid (TCA) it is one to three minutes, before being neutralised. All other peels have varying exposure times.

Ideally, practitioners should use a neutraliser that can not only neutralise any surface acid, but also neutralise acid released in the skin. Alkaline amino acids are useful as a neutraliser as they can be attached to the same carrier molecules as used with the acids; in other words, wherever the carrier has taken the acid in the skin, the neutraliser can follow and neutralise both on and in the skin.

Something like sodium bicarbonate is too big a molecule to carry into the skin and hence only neutralises on the surface.12

Mandelic usage has become more varied from a traditional ten-minute exposure and then neutralised, to also include now a partially extended or fully extended peel like a Jessner’s, whereby the solutions are left active in the skin and only any remaining unabsorbed solution is removed at ten minutes. The mandelate attached to the carrier 1,2,3,4 is allowed to be released in the skin and convert to mandelic acid and is still active post the patient leaving the clinic, thereby extending the peels activity and boosting the results.

With Jessner’s, the peel is not neutralised but only the salicylate white powder is removed, that forms on the surface, as the salicylic acid deactivates and converts to this analgesic powder leaving the lactic acid and resorcinol components active to continue to target the tyrosinase enzyme to help reduce excess pigmentation.

The value of bespoke treatment protocols

When you have just a range of different peels rather than one type of peel solution such as glycolic, you can change the focus of the treatment to target other issues during a course of treatment, should the patient’s initial skin condition be resolved during the course of treatment allowing you to focus on other skin issues.

Bespoke peels allow the practitioner to switch and change peel choice during a course of treatment, depending on the patient’s skin journey and what changes take place during the treatment programme.

The correct patient assessment, prescription for the right areas and using the right exposure time leads to optimum outcomes for all patients.


1. Enerpeel 50% Pyruvic Acid Comparison with 70% Glycolic Acid – Shuller Petrovic, Mayr-Kanhaauser – UnivGraz, Austria 2003
2. Enerpeel PA efficacy and safety evaluation versus 50% pyruvic acid – Prof Bonina – Univ Catania, Italy, August 2003
3. Clinical evaluation of Enerpeel PA – Prof Beradesca S. Maria e S. Gallicano Derm. Institute, Rome – July 2004
4. Berardesca E, Cameli N, Primavera G, Carrera M. Clinicaland Instrumental Evaluation of Skin Improvement after Treatment with a New 50% Pyruvic Acid Peel. Dermatol Surg. 2006;32:526–31.
5. Salicylic Acid peel incorporating Triethyl citrate and Ethyl linoleate (ENERPEEL SA) in the treatment of acne: a new therapeutic approach.
6. Raone B, Patrizi A Internal Medicine, Aging and Nephrologic Diseases Department, Division of Dermatology, Sant’Orsola- Malpighi Hospital, University of Bologna, Bologna, Italy. Data on File
7. Open Multicentric Study to test the efficacy of a new therapeutic protocol of acne vulgaris
8. Data on File
9. Journal of Aesthetic. Plastic. Surgery. 26:99-104, 2002 Fabil Fanous – Montreal, Quebec, Canada)
10. Tasaka K, Kamei C, Nakano S, Takeuchi Y, Yamato M. Effects of certain resorcinol derivatives on the tyrosinase activity and the growth of melanoma cells, Methods Find Exp Clin Pharmacol. (1998) www.ncbi. nlm.nih.gov/pubmed/9604851
11. Mark B Taylor, Summary of Mandelic Acid for the Improvement of Skin Conditions, http://dermage.com.br/dermage/paginas/ article.pdf
12. Shannon Farrell, Control oily skin with a skin peel, (2015) http://stylecaster.com/beauty/how-to-control-oily-skin/
13. Canadian Dermatology Association, Know your skin type, (2017) www.dermatology.ca/skin-hair-nails/skin/photoaging/knowyour-skin-type/
14. CQConcepts, Sodium Bicarbonate Technical Grade, (2007) www.cqconcepts.com/chem_sodiumbicarbonate.php

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