Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Adverse effects
Systematic review	20 women, aged 42–72 years, with Fitzpatrick skin types I–III on the upper lip Data from 1 RCT	Erythema with carbon dioxide laser alone with carbon dioxide laser plus variable pulse erbium:YAG laser	Reported as not significant P value not reported		Not significant
Systematic review	20 women, aged 42–72 years, with Fitzpatrick skin types I–III on the upper lip Data from 1 RCT	Pain with carbon dioxide laser alone with carbon dioxide laser plus variable pulse erbium:YAG laser	Reported as not significant P value not reported		Not significant