Table 2.

Study population with efficacy and adverse effects of chemical peels

Author	Population and acne Characteristics	Outcome of study	Tolerability
Kessler, et al., 2008 (13).	N= 20, American patients, (13-35) year, with Acne vulgaris mild to moderate inflamed pimple, two months duration study.	Both GA and SA peels were significantly effective by the second treatment and there were no significant differences in effectiveness between the two peels. SA peel showed sustained effectiveness two months post-treatment. More adverse events were reported with the GA peel.	Safety peeling for both GA and SA, mild complications increased after the first treatment and decreasing after the frequent treatments.
Hashimoto et al.,2008 (10).	N= 16, Japanese patients, (16-29) years with mostly severity acne, comedonal acne (less than (10) papules or pustules), Medications allowed, two and half months duration study.	Comedones are reduced to 75%. The mean total facial comedones count, was decreased from 39.3 at baseline to 9.2 after 10 weeks treatment by the time of completion of the study.	Mild burning sensation and erythema were noted in 8.8% of patients treated with SA.
Dainichi et al.,2008 (9).	N = 436, Japanese patient, (17-46) years, patients having comedonal acne, nodulo-cystic acne, concomitant acne and redness. Three months study period.	Comedones are significant improvement (greater than 75% clearance of lesions occurred). Scanning electron microscopy after 1 week treatment with 30% SA revealed a restoration of the regular grooves of the skin and removal of the cornified plugs from the hair follicles.	No complaints of pain, burning, or stinging and no signs of edema, bleeding, crusting, or post-inflammatory pigmentation.
Garg et al., 2009 (14).	N = 44, Indian patients, (16 -27) years, with acne vulgaris and post-acne scarring and hyperpigmentation. Treated for 24 week	Both GA and SA peels decrease the comedones; SA had a higher efficacy for most active acne lesions (P<0.001) and hyperpigmentation (P<0.001). SA peels for comedones and papules showed a significant improvement 4 weeks earlier than GA	Adverse effects were less common with SA (24% than GA with 40%. Also 17.3% patients developed a burning or stinging sensation. In treatment with GA peels 8.7% of the patients had visible desquamation. Dryness was seen more often with SA treatment (14.28%). Photosensitivity and initial acne flare were same among both GA and SA groups.
Dréno et al., 2011(15).	N = 397, pacientes com (30-40) anos com pele de fototipos (II-IV), e estudo com duração de 3 meses.	Inflammatory and retentional lesions were reduced in mild cases after three months. Both open and closed comedones decreased significantly during study period.	Adverse effects were infrequent with some patients complaint of irritation, tightening, pruritus, and 96.7% of the patients did not encounter any adverse effect
Kim et al., 1999 (8)	N = 26, Korean patients; (16 - 27) years, mild-to-moderate severity; (III-IV) skin type; concomitant acne treatment; without acne treatment, study period for three months.	After the first treatment session, the severity of acne had not changed among most of the patients. But after the third session, 50 % of the patients treated with either GA or Jessner's solution showed improvement. No significant differences in treatment effects between the 2 methods.	More adverse effects seen by Jessner's solution as erythema and exfoliation form compared to GA (p < 0.01).
Atzori et al., 1999 (11).	N = 80, Italian patients (16 - 27) years, with comedonal acne, nodulo- cystic and papulo-pustular concomitant acne. Study period for 2 years.	Rapid improvement was observed in comedonic acne within three applications of GA. In the papulo-pustular significant improvement was achieved by the fourth application. Nodular-cystic forms required eight to ten applications	A minimal inflammatory lesions developed in 20% of the patients. one patient had tenacious erythema.