Evidence Level C
Poor quality observational (cohort) studies or methodologically flawed randomized controlled trials (RCTs) of <200 participants.
Reduction in number of inflammatory lesions in mild to severe acne: there is poor-quality evidence that, compared with placebo or vehicle agent, topical clindamycin 1% reduced the number of inflammatory lesions at 8 to 12 weeks.
More info from BMJ Clinical Evidence
