Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Improvement in wrinkles
RCT	20 women, aged 51–71 years, with Fitzpatrick skin type I–III and with wrinkles on upper lip In review	Average change in upper lip wrinkle score (6-point scale: 0 = none to 5 = severe) baseline to 6 months from 4.30 to 1.11 with carbon dioxide laser from 4.20 to 0.47 with Baker's phenol chemical peel	P <0.03	Effect size not calculated	Baker's phenol chemical peel
RCT	24 men and women, aged 43–73 years, with Fitzpatrick skin types I–III	Severity of periorbital wrinkles (6-point scale: 0 = none to 5 = severe) baseline to 6 months from 4.00 to 1.75 with carbon dioxide laser from 4.13 to 3.29 with trichloroacetic acid chemical peel	P <0.001	Effect size not calculated	carbon dioxide laser