Clinical and Instrumental Evaluation of SkinImprovement after Treatment with a New 50%Pyruvic Acid Peel

ENZO BERARDESCA, MD, NORMA CAMELI, MD, GRAZIA PRIMAVERA, MD,

AND MANUELA CARRERA, MD�

BACKGROUND Pyruvic acid is an a-keto acid that presents keratolytic, antimicrobial, andsebostatic properties as well as the ability to stimulate new collagen production andelastic fibers formation. Because of its low pKa and its small dimension, it penetratesrapidly and deeply through the skin, so far as to be considered a potent chemical peelagent. It has proven its efficacy for the treatment of many dermatological conditions suchas acne, superficial scarring, photodamage, and pigmentary disorders. Pyruvic acid ap-plication usually induces intense burning, and the postpeeling period is characterized byerythema, desquamation, and, sometimes, crusting.

OBJECTIVE The aim of the study is to assess the efficacy and tolerability of 50% pyruvicacid in a new non-erythematogenic formulation (pyruvic acid 50%, dimethyl isosorbide,propylene glycol, ethyl alcohol, dimethyl sulfone, ethyl lactate, water) for the treatment ofphotodamage, superficial scarring, and melasma.

MATERIALS AND METHODS Twenty subjects affected by photodamage, superficial scar-ring, and melasma, but otherwise healthy, entered the study. Four peeling sessions wereperformed once every 2 weeks. The patients were evaluated clinically and by means ofseveral noninvasive methods in order to monitor the following parameters: hydration,color (erythema and pigmentation), elasticity, skin smoothness, skin roughness, scaliness,and wrinkles.

RESULTS The patients did not report any discomfort either during the peeling session orduring the postpeeling period, without any impact on their social life. We did not observeany case of persistent erythema as well as any case of postinflammatory hyperpigmen-tation. Instrumental evaluations showed a significant reduction in the degree of pigmen-tation in patients with melasma, a significant increase in skin elasticity, and animprovement of the degree of wrinkling in all the patients.

CONCLUSION This innovative formulation of 50% pyruvic acid peel has been shown to besafe and effective to treat photodamage, melasma, and superficial scarring, allowing thepatients to carry out regularly their working life as well as their social life. Furthermore, theresults have been evaluated by means of noninvasive devices, which have permitted oneto quantify the improvements.

The peeling solution used in this study was provided by General Topics, Salo, Italy.

The history of chemical peel-

ing1 started from ancient

times with the Egyptians bathing

in sour milk to smooth their skin,

thus exploiting the properties of

an a-hydroxy acid contained

therein: lactic acid. Tilbury Fox

has to be considered the pioneer

dermatologist in the matter of

chemical peelings as he described

for the first time in 1871 the use

of 20% phenol to lighten the skin.

About 10 years later, P.G. Unna

reported the properties of salicylic

acid, resorcinol, phenol, and

trichloroacetic acid. In scientific

literature, some rare reports con-

cerning peeling were published in

the first half of the 20th century

but, until 1972 when Gordon and

Baker documented by photogra-

& 2006 by the American Society for Dermatologic Surgery, Inc. � Published by Blackwell Publishing �ISSN: 1076-0512 � Dermatol Surg 2006;32:526–531 � DOI: 10.1111/j.1524-4725.2006.32106.x

5 2 6

�All authors are affiliated with Dermatological Institute S. Maria and S. Gallicano, IRCCS, Rome, Italy

phy the excellent results obtained

using a mysterious formula for the

treatment of wrinkles, physicians

were doubtful about the real effi-

cacy of chemical peeling. In

the 1980s, Van Scott and Yu

performed the first peelings with

a-hydroxy acids, which attracted

the media’s attention in the 1990s.

Since then and because of the

media’s promotion, chemical

peeling has become popular as a

way to improve skin appearance,

minimizing wrinkles, irregular

pigmentation, melasma,

lentigines, actinic keratoses,

wrinkling, roughness, and

superficial scars.

Chemoexfoliation dermal peeling

consists of the application of one

or more chemical agents to the

skin, resulting in skin resurfacing

with the formation of new colla-

gen and reorganization of the

elastic fibers in the skin. Chemical

peeling is classsified on the basis

of the depth of skin injury as su-

perficial, medium, and deep peels.

The intensity of the peel is not

only due to the chemical agent but

it results from several parameters:

the concentration of the acid, the

pH of the solution, the vehicle in

which the acid is contained, the

amount of acid applied on the

skin, and the method of delivering

the acid. Superficial peels are the

most widely used because of the

necessity of minimal recovery

time whereas medium-depth peels

usually require a longer post-

peeling period. Actually, a wide

range of peeling agents are avail-

able. The choice of the chemical

agent is based on Fitzpatrick skin

type and on the Glogau classifi-

cation.2

Pyruvic acid is an a-keto acid

whose use has first been described

in the scientific literature in 1996

by Moy and colleagues,3 who

pointed out its keratolytic, anti-

microbial, sebostatic properties as

well as its capability to stimulate

the formation of collagen and

elastic fibers. Pyruvic acid has

always been considered a very

potent acid, and it has been

included in the group of medium-

depth peeling agents.4

The aim of this study was to

evaluate the efficacy and tolera-

bility of peeling with 50% pyruvic

acid in a new preparation, for the

treatment of photodamage, pig-

mentary dischromias, superficial

scarring, and melasma of

facial skin.

This new 50% pyruvic acid is

formulated with a technology that

results in epidermal increased skin

absorption of the acid, homoge-

neous absorption of the acid, and

reduced skin irritation due to the

addition of dimethyl sulfone,

which acts as an inflammatory

ingredient.5 The balance between

efficacy and side effects is the art

in peeling.

The permeation of different com-

pounds onto the skin is directly

correlated to the polar and lipid

routes, and polar and lipid pene-

trants are characterized by differ-

ent kinetics of absorption. The

middle-strong organic acid (AHA,

a-keto acids, etc.) are typically

dissociated in water. This dissoci-

ation defines the strength of the

acid. The activity of the acid in

the superficial layer of the skin,

the horny layer, is limited by the

lipid structure, because the release

of the proton depends on the

aqueous medium. This new tech-

nology can incorporate the hy-

drophilic acid and carrier the

same towards the lipidic struc-

tures to the proteic components of

the skin (keratin, desmosomes,

etc.) where the smoothing and

keratolytic effect can take place.

This technology can increase the

release of the proton (the pH is

lower if compared with a normal

water solution of the same acid at

the same concentration), and it

seems to diminish the mobility of

the same proton. Once the acid is

carried into a hydrophilic struc-

ture, the mobility of the proton

increases, and the chemo exfolia-

ting effect can effectively take

place. The result of such a condi-

tion is that the epidermal turnover

is accelerated, and desquamation

is less marked if compared with

an aqueous solution of the same

acid at the same concentration.

Materials and Methods

Twenty subjects affected by pho-

todamage, superficial scarring, or

melasma, but otherwise healthy,

entered the study. Patients were

evaluated carefully before starting

treatment. Our patients presented

Fitzpatrick skin types II to III and

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B E R A R D E S C A E T A L

Glogau photoaging scale types I,

II, and III (mild to advanced).

Further factors were considered

and exclusion criteria were as

follows:

� Pregnant or nursing subjects.

� Previous recent (2–6 months)

aesthetic surgery (blepharopla-

sty, rhytidectomy, brow lift) in

the treatment area.

� Active herpes simplex in the

treatment area.

� Immunocompromising diseases

(possibility of delayed healing,

increased susceptibility to infec-

tion or excessive pigmentation

after peeling).

� Previous facial radiation ther-

apy that might impair the ability

of the skin to regenerate.

� Recent isotretinoin treatment.

� Hypertrophic scarring.

� Keloids.

� Allergies.

� Subjects with significant history

or current evidence of any psy-

chological disorder that, in the

investigator’s opinion, would pre-

clude enrolment into the study.

After degreasing the skin with a

defatting solution, the timer was

set up according to the applica-

tion time based on the skin type

and the Glogau-Fitzpatrick index

(GF index). The time of applica-

tion ranged between 3 and 5

minutes. The 50% pyruvic acid

was applied using the special ap-

plicator. The peel was then neu-

tralized with a 10% sodium

bicarbonate in water solution

when the time warning signal

started ringing. Immediately after

the procedure, an emollient facial

cream was applied to the treated

areas, and patients were instruct-

ed to apply a moisturizing cream

twice daily for a week, to avoid

sun exposure, and to use sun-

screens daily.

Four peeling sessions were per-

formed once every 2 weeks.

Patients were evaluated with non-

invasive methods at baseline, every

2 weeks before performing the

peeling, and 90 days after the first

peeling because it is the necessary

time for collagen remodelling.

Several parameters were moni-

tored as follows:

� Hydration: Skin surface hydra-

tion was determined with the

Corneometers CM 825 (Cour-

age & Khazaka, Koln,

Germany). The measuring prin-

ciple of this instrument is based

on capacitance measurement of

a dielectric medium. Any

change in the dielectric constant

because of skin surface

hydration variation alters the

capacitance of a precision

measuring capacitor.

� Color: The color of the skin is

mainly due to two components:

melanin and hemoglobin (ery-

thema). Mexameters MX 18

(Courage & Khazaka) was used

to assess melanin content and

erythema level. The measure-

ment is based on absorption/re-

flection. The probe emits three

specific light wavelengths, and a

receiver measures the light re-

flected by the skin. The melanin

content and the erythema level

are measured by specific wave-

lengths corresponding to the

spectral absorption peak of each

pigment. The results for both

parameters are immediately

shown as index numbers. The

values range from 0 (white) to

1,000 (black). The mexameter

has an accuracy of 75%.

� Elasticity: The elasticity of the

skin is evaluated by the Cuto-

meters MPA 580 (Courage &

Khazaka). The measuring prin-

ciple is based on the suction

method. Negative pressure is

created in the device, and the

skin is drawn into the aperture

of the probe. The resistance of

the skin to be sucked up by the

negative pressure (firmness) and

its ability to return to its origi-

nal position (elasticity) are dis-

played as curves at the end of

each measurement.

� Skin smoothness, skin rough-

ness, scaliness, wrinkles: These

four clinical parameters describe

quantitatively and qualitatively

the skin surface; they are meas-

ured by a special UV-light video

camera (Visioscans VC, Cour-

age & Khazaka). The images of

the skin surface are elaborated

by a particular software that

permits the calculation of the

parameters. Thus, before and

after treatment comparisons of

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the same skin site enable a

comparison of trends in skin

condition.

Until now, profilometry has been

the only method to determine the

condition of skin surface, other

than subjective evaluation. By

means of a Visioscans VC, skin

can be monitored optically, using a

new method called surface evalu-

ation of the living skin (SELS). The

parameters evaluated have been

developed in various clinical stud-

ies in order to be perfectly suitable

to characterize the skin surface.

Skin smoothness (SEsm) is the

calculation from the average width

and depth of wrinkles. Skin

roughness (SEr) is the opposite

parameter. The scaliness (SEsc)

measures the level of dryness of the

stratum corneum. The wrinkles

(SEw) derive from the proportion

of horizontal and vertical wrinkles.

Measurements have been per-

formed at 7 201C of environ-

mental temperature with a

relative humidity of 4575% ac-

cording to guidelines published

for these techniques.

At baseline and during each peeling

session, a clinical evaluation of the

patients was performed by the

investigator using digital photog-

raphy documentation and a visual

numerical scale (0–10) to assess the

patients’ view of skin appearance.

The evaluated parameters were as

follows:

� Redness during the peeling pro-

cedure.

� Burning during the peeling pro-

cedure.

� Discomfort (erythema, desqua-

mation, irritation, crusting) in

the post-peeling period.

� Hydration.

� Elasticity.

� Color.

Statistical analysis was performed

using the t test. Values of po.05

were considered statistically sig-

nificant.

Results

After four peeling sessions, we ap-

preciate a global improvement in

skin aspect which appears lighter,

especially in patients affected by

melasma, more tense, and less fur-

rowed (Figures 1–3). We did not

observe any case of persistent ery-

thema as well as any case of post-

inflammatory hyperpigmentation.

The patients reported lightening

of the skin, improvement of the

skin’s elasticity, reduction of

wrinkling, and dryness of the

skin. Whereas the application of

pyruvic acid usually causes a

very intense burning sensation,

with this new formulation the

patients referred to moderate

stinging and burning sensations

that faded in a few minutes after

the neutralization of the acid.

Furthermore, most of the patients

presented only a mild erythema

immediately after the peeling and

did not report any discomfort

during the postpeeling period,

such as desquamation, irritation,

erythema or crusting, without any

impact on their social life. All the

patients were satisfied with the

treatment.

The evaluation performed by

means of non-invasive devices

confirmed the clinical data.

Figure 1. Marked clinical improvement after four peelings of superficial scarringin a patient affected by acne.

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B E R A R D E S C A E T A L

The results after four peeling ses-

sions (the last evaluation was

performed 1 month after the

fourth peeling) show a significant

increase of skin elasticity (Figure

4, po.05) in all the patients, and

a significant reduction in the de-

gree of pigmentation (Figure 5, p

o.05) in patients with melasma.

The evaluation of erythema is

slightly higher compared with the

baseline and the skin hydration

results decreased, but these changes

are not statistically significant. With

regard to the parameters evaluated

with the Visioscans VC, there is a

significant (Figure 6, po.05) im-

provement in the degree of wrinkl-

ing (number and width of wrinkles)

as shown by the decreased values of

the SEw parameter.

Discussion

In recent years, patients seeking

medical procedures that improve

their skin appearance have greatly

increased; furthermore, they ask

for soft therapeutic options that

provide benefits without compli-

cations and without a long re-

covery time. Pyruvic acid is an a-

keto acid, which is a carboxylic

acid having a keto group at the aposition of the aliphatic carbon

atom. Pyruvic acid is physiologi-

cally in equilibrium with lactic

acid as lactate dehydrogenase

converts each acid into the other.

It is considered a potent acid be-

cause its small molecule allows

deep penetration and its pKa is

low (about 2.4). It presents

keratolytic, antimicrobial,

sebostatic effects, and stimulates

Figure 3. Marked reduction of acne scarring and pigmentation.

Figure 2. Improvement of skin photoaging with reduction of periocular lines,pigmentation, and improvement of skin texture.

0.0000

0.5000

1.0000

1.5000

T0 T1 T2 T3 T4

ELASTICITY

R6

Figure 4. Significant increase in skin elasticity after four peelings (po.05).T = time; T1 = after the first peeling, etc.

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collagen and elastic fiber forma-

tion.4 Pyruvic acid has been

employed as a medium chemical

peeling agent, in concentrations

ranging from 40 to 70% and

has only recently attracted atten-

tion on the basis of the clinical

evidence of its capability to

treat several skin conditions such

as wrinkles, pigmentary

disorders, acne, and superficial

scarring.6,7 It has proven to be

effective and safe and to combine

better results and fewer side

effects compared with the most

commonly used peeling agents.

Acidity is very important for

efficacy and absorption of the

chemical agent, but it is also re-

sponsible for side effects. In this

study we have employed an inno-

vative formulation of 50%

pyruvic acid containing special

ingredients, which associates good

efficacy and less discomfort in the

postpeeling period. Compared

with the pH value of a non-

buffered aqueous solution of

50% pyruvic acid (pH = 0.1050),

the pH value of this new formu-

lation is significantly lower

(pH =�0.5086), resulting in an

increased absorption.

With this innovative formulation

of 50% pyruvic acid, we have

successfully treated 20 subjects

affected by photodamage, super-

ficial scarring, or melasma with-

out any unwanted effect, allowing

the patients to carry out regularly

their working life as well as their

social life.

In this report, the results obtained

by peelings with this new 50%

pyruvic acid have been evaluated

not only subjectively but also by

means of several non-invasive de-

vices that have permitted us to

quantify improvement in terms of

degree of pigmentation, erythema,

and especially elasticity and de-

gree of wrinkling.

References

1. Brody HJ, Monheit GD, Resnik SS, Alt

TH. A history of chemical peeling. Der-

matol Surg 2000;26:405–9.

2. Glogau RG. Chemical peeling and aging

skin. I Geriatr Dermatol 1994;2:30–5.

3. Moy LS, Peace S, Moy RL. Comparison of

the effects of various chemical peeling

agents in a mini-pig model. Dermatol Surg

1996;22:429–32.

4. Monheit GD. Medium-depth combination

peels. Dermatol Ther 2000;13:183–91.

5. Data on file, General Topics srl, Salo,

Italy.

6. Griffin TD, Van Scott EJ, Maddin S. The

use of pyruvic acid as a chemical peeling

agent. J Dermatol Surg Oncol 1989;

15:1316–20.

7. Cotelessa C, Manunta T, Ghersetich I,

Brazzini B, Peris K. The use of pyruvic acid

in the treatment of acne. J Eur Acad

Dermatol Venereol 2004;18:275–8.

8. Ghersetich I, Brazzini B, Peris K, Cotel-

lessa C, Manunta T, Lotti T. Pyruvic acid

peels for the treatment of photoaging.

Dermatol Surg 2004;30:32–36.

Address correspondence and reprintrequests to: Enzo Berardesca, MD,San Gallicano DermatologicalInstitute, Via Chianesi 53, 00144Rome, Italy, or e-mail: berardesca@berardesca.it

0

50

100

150

200

250

T0 T1 T2 T3 T4

MELANIN

PIGMENTATION

Figure 5. Significant decrease of pigmentation as measured by a mexameter(po.05). T = time; T1 = after the first peeling, etc.

3233

3435

3637

38

T0 T1 T2 T3 T4

Sew

DEGREE OF WRINKLING

Figure 6. Significant decrease of wrinkles (Sew parameter, po.05).T = time; T1 = after the first peeling, etc.

3 2 : 4 : A P R I L 2 0 0 6 5 3 1

B E R A R D E S C A E T A L