Bae 2013.

Study characteristics
Methods	Aim of study: to compare the effectiveness and side effects of SA peels and Jessner's solution peels in the treatment of acne using a split‐face model Design: within subjects, split‐face design Unit of allocation: split‐face Allocation: randomised; no details of random sequence generation methods Blinding: evaluator blinded only Duration of trial (from recruitment to last follow‐up): not described Dropouts: none
Participants	Population description: mild to moderate acne according to the Cunliffe grading system Setting: university setting in Korea Randomised number: 13 Age: mean: 22.6; range: 20 to 28 Sex (M/F): 13/0 Severity of illness: mild to moderate Non‐inflammatory lesion counts: 18.6 ± 20.9 in one side of face versus 22.7 ± 26.2 in other side; Inflammatory lesion counts: 14.2 ± 6.0 versus 12.5 ± 7.8
Interventions	Name of treatment group: 30% SA n = 13 faces Description: 30% SA Treatment period: 4 weeks Timing: three times every 2 weeks Name of treatment group: Jessner's solution n = 13 faces Description: 14 g of resorcinol, 14 g of SA, 14 mL of lactic acid, and ethanol quantum satis 100 mL Treatment period: 4 weeks Timing: three times every 2 weeks
Outcomes	Primary outcomes (see notes) Participants' global self‐assessment of acne improvement (e.g. measured by a 4‐point scale: excellent, good, fair, and poor; week 6; 4‐point scale: 3 = good improvement, 2 = moderate improvement, 1 = mild improvement, 0 = no improvement or worsening) Withdrawal for any reason (no withdrawals) Secondary outcomes Change in lesion counts (total or inflamed and non‐inflamed separately). Mean lesion counts at baseline, week 2, 4, and 6 Physicians' global evaluation of acne improvement. Authors did not report this outcome Minor adverse events (assessed as total number of participants who experienced at least one minor adverse event). Only mentioned but data not usable Quality of life. Authors did not report this outcome.
Notes	Funding: not described This was a 'split‐face'. According to the protocol of this review, only summary statistics were used to conduct analysis using the generic inverse variance method and it was separate from parallel trials.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Split‐face, within‐subjects design study. No randomisation method was described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "Double blinding was impossible because the two chemical peels showed different acute responses" Comment: blinding probably insufficient
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "the evaluator blinding method was used" Comment: insufficient information about method to ensure blinding of outcome assessor
Incomplete outcome data (attrition bias) All outcomes	Low risk	All the 13 participants completed the study, no missing outcome data
Selective reporting (reporting bias)	Unclear risk	Insufficient data regarding subject global assessment
Other bias	Low risk	No other potential bias identified