Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Improvement in fine wrinkles (tretinoin 0.001%)
Systematic review	147 people with mild to moderate photodamage Data from 1 RCT	Proportion of people with improved fine facial wrinkles (physician-assessed) 24 weeks 20/75 (27%) with topical tretinoin 0.001% (once-daily for 24 weeks) 28/72 (39%) with vehicle cream (once-daily for 24 weeks)	RR 0.69 95% CI 0.43 to 1.10 RCTs identified by review had methodological limitations; see Further information on studies for full details		Not significant
Improvement in fine wrinkles (tretinoin 0.01%)
Systematic review	345 people with mild to moderate photodamage 3 RCTs in this analysis	Proportion of people with improved fine facial wrinkles (physician-assessed) 24 weeks 93/174 (53%) with topical tretinoin 0.01% (once-daily for 24 weeks) 63/171 (37%) with vehicle cream (once-daily for 24 weeks)	RR 1.57 95% CI 0.91 to 2.71 RCTs identified by review had methodological limitations; see Further information on studies for full details		Not significant
Systematic review	34 people with mild to moderate photodamage of the face and forearms Data from 1 RCT	Proportion of people with improved fine forearm wrinkles (physician-assessed) 24 weeks 24/34 (71%) with topical tretinoin 0.01% (once-daily for 24 weeks) 1/34 (3%) with vehicle cream (once-daily for 24 weeks)	P <0.01 RCTs identified by review had methodological limitations; see Further information on studies for full details	Effect size not calculated	tretinoin 0.01%
Improvement in fine wrinkles (tretinoin 0.02%)
Systematic review	328 people with moderate to severe photodamage 2 RCTs in this analysis	Proportion of people with improved fine facial wrinkles (physician-assessed) 24 weeks 98/159 (62%) with topical tretinoin 0.02% (once-daily for 24 weeks) 65/169 (39%) with vehicle cream (once-daily for 24 weeks)	RR 1.60 95% CI 1.28 to 2.01 RCTs identified by review had methodological limitations; see Further information on studies for full details	Small effect size	tretinoin 0.02%
Improvement in fine wrinkles (tretinoin 0.025%)
Systematic review	67 people with moderate to severe photodamage Data from 1 RCT	Mean improvement in fine facial wrinkle score (physician-assessed using a 10-point scale) 48 weeks 1.3 with topical tretinoin 0.025% (once-daily for 48 weeks) 0.6 with vehicle cream (once-daily for 48 weeks)	WMD 0.75 95% CI 0.22 to 1.28 RCTs identified by review had methodological limitations; see Further information on studies for full details	Effect size not calculated	tretinoin 0.025%
Improvement in fine wrinkles (tretinoin 0.05%)
Systematic review	593 people with mild to moderate photodamage 5 RCTs in this analysis	Proportion of people with improved fine facial wrinkles 24 weeks 186/298 (62%) with topical tretinoin 0.05% (once-daily for 24 weeks) 102/295 (35%) with vehicle cream (once-daily for 24 weeks)	RR 1.76 95% CI 1.47 to 2.12 RCTs identified by review had methodological limitations; see Further information on studies for full details	Small effect size	tretinoin 0.05%
Systematic review	125 people with mild to moderate photodamage Data from 1 RCT	Proportion of people with improved fine forearm wrinkles (physician-assessed) 24 weeks 32/62 (52%) with topical tretinoin 0.05% (once-daily for 24 weeks) 22/63 (35%) with vehicle cream (once-daily for 24 weeks)	RR 1.48 95% CI 0.98 to 2.24 RCTs identified by review had methodological limitations; see Further information on studies for full details		Not significant
Improvement in fine wrinkles (tretinoin 0.1%)
Systematic review	30 people with photodamage of the face and forearms Data from 1 RCT	Proportion of people with improved fine facial wrinkles (physician-assessed) 16 weeks 14/15 (93%) with topical tretinoin 0.1% (once-daily for 16 weeks) 0/15 (0%) with vehicle cream (once-daily for 16 weeks)	RR 29.00 95% CI 1.89 to 445.86 RCTs identified by review had methodological limitations; see Further information on studies for full details	Large effect size	tretinoin 0.1%
Systematic review	30 people Data from 1 RCT	Proportion of people with improved fine forearm wrinkles 16 weeks 30/30 (100%) with topical tretinoin 0.1% (once-daily for 16 weeks) 0/30 (0%) with vehicle cream (once-daily for 16 weeks)	P <0.001 RCTs identified by review had methodological limitations; see Further information on studies for full details	Effect size not calculated	tretinoin 0.1%
RCT	45 people with moderate to severe facial photodamage	Proportion of people with improved fine facial wrinkles (physician- and patient-assessed) 6 months 94% with tretinoin 0.1% (microsphere gel preparation; applied once-daily for 6 months) 23% with vehicle gel (applied once-daily for 6 months) Absolute numbers not reported	P <0.0001 Method of randomisation and allocation concealment were unclear	Effect size not calculated	tretinoin 0.1%
Improvement in coarse wrinkles (tretinoin 0.01%)
Systematic review	34 people with mild to moderate photodamage of the face and forearms Data from 1 RCT	Proportion of people with improved coarse facial wrinkles (physician-assessed) 24 weeks 7/17 (41%) with topical tretinoin 0.01% (once-daily for 24 weeks) 1/17 (6%) with vehicle cream (once-daily for 24 weeks)	RR 7.00 95% CI 0.96 to 50.93 RCTs identified by review had methodological limitations; see Further information on studies for full details		Not significant
Improvement in coarse wrinkles (tretinoin 0.02%)
Systematic review	328 people with moderate to severe photodamage 2 RCTs in this analysis	Proportion of people with improved coarse facial wrinkles (physician-assessed) 24 weeks 64/159 (40%) with topical tretinoin 0.02% (once-daily for 24 weeks) 40/169 (24%) with vehicle cream (once-daily for 24 weeks)	RR 1.70 95% CI 1.22 to 2.37 RCTs identified by review had methodological limitations; see Further information on studies for full details	Small effect size	tretinoin 0.02%
Improvement in coarse wrinkles (tretinoin 0.05%)
Systematic review	162 people with mild to moderate photodamage 2 RCTs in this analysis	Proportion of people with improved coarse facial wrinkles (physician-assessed) 24 weeks 41/79 (52%) with topical tretinoin 0.05% (once-daily for 24 weeks) 25/83 (30%) with vehicle cream (once-daily for 24 weeks)	RR 1.68 95% CI 1.17 to 2.42 RCTs identified by review had methodological limitations; see Further information on studies for full details	Small effect size	tretinoin 0.05%
Improvement in coarse wrinkles (tretinoin 0.1%)
Systematic review	30 people with mild to moderate photodamage of the face and forearms Data from 1 RCT	Proportion of people with improved coarse facial wrinkles (physician-assessed) 16 weeks 6/15 (40%) with topical tretinoin 0.1% (once-daily for 16 weeks) 0/15 (0%) with vehicle cream (once-daily for 16 weeks)	RR 13.0 95% CI 0.80 to 212.02 RCTs identified by review had methodological limitations; see Further information on studies for full details		Not significant
Systematic review	30 people Data from 1 RCT	Proportion of people with improved coarse forearm wrinkles 16 weeks 9/30 (30%) with topical tretinoin 0.1% (once-daily for 16 weeks) 0/30 (0%) with vehicle cream (once-daily for 16 weeks)	P <0.01 RCTs identified by review had methodological limitations; see Further information on studies for full details	Effect size not calculated	tretinoin 0.1%
RCT	45 people with moderate to severe facial photodamage	Proportion of people with improved coarse facial wrinkles (physician- and patient-assessed) 6 months 22% with tretinoin 0.1% (microsphere gel preparation; applied once-daily for 6 months) 5% with vehicle gel (applied once-daily for 6 months) Absolute numbers not reported	P = 0.1 Method of randomisation and allocation concealment were unclear		Not significant
Improvement in wrinkles (global; tretinoin 0.1%)
RCT	45 people with moderate to severe facial photodamage	Global assessment score (investigators and participants scored signs of photodamage and skin irritation, using a scale from 0–9 [0 = none, 1–3 = mild, 4–6 = moderate, 7–9 = severe]) 6 months with tretinoin 0.1% (microsphere gel preparation; applied once-daily for 6 months) with vehicle gel (applied once-daily for 6 months) Absolute results reported graphically	P <0.0003 Method of randomisation and allocation concealment were unclear	Effect size not calculated	tretinoin 0.1%
RCT	45 people with moderate to severe facial photodamage	Proportion of people with improved facial tactile roughness (physician- and patient-assessed) 6 months 83% with tretinoin 0.1% (microsphere gel preparation; applied once-daily for 6 months) 91% with vehicle gel (applied once-daily for 6 months) Absolute numbers not reported	P = 0.53 Method of randomisation and allocation concealment were unclear		Not significant