Lachnit‐Fixson 1977.

Methods	Multicenter trial in Germany and Austria. Participant and investigators were blinded. 6 to 12 treatment cycles.
Participants	88 women aged 16 to 45 years with acne, seborrhea or hirsutism graded from none to severe. Excluded women with contraindications to oral contraceptives or abnormal gynecological evaluation.
Interventions	Group 1: CPA 2 mg plus EE 50 µg Group 2: LNG 250 µg plus EE 50 µg
Outcomes	Clinician global assessment.
Notes	Randomization method not stated. No information on allocation concealment before assignment. Pills distributed in numbered kits with 21‐day pill packs.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	No information