Guerrero 2009.

Methods	This was a randomised, active‐controlled trial Setting 3 centres in Chile Date of study November 2007 to April 2008 (12‐week duration)
Participants	40 men and women (22 men, 18 women) Mean age = 43.7 years (range 20 to 69) Inclusion criteria Androgenetic alopecia according to Hamilton for men and Ludwig for women (Ludwig 1977). Informed consent, and willing to comply and attend visits to the clinic. Exclusion criteria Hormonal treatment in previous 3 months. Diseases interfering with alopecia. Pregnant and lactating women. Hair diseases that worsen with topical applications. Treatments that affect hair growth such as lithium and methotrexate. Hypersensitivity to 1 of the ingredients. Hair transplant. Randomised 40 participants were randomised (minoxidil group = 15, estradiol group 18, unclear = 7) Withdrawals/losses to follow‐up 7/40 (18%) withdrawals/losses to follow‐up: unclear how many from each group Not attending primary visit (2) control visits (3), adverse events (1), pregnancy and subsequent spontaneous abortion (1). Baseline data Most men had Hamilton II/III and most women Ludwig II
Interventions	Intervention Minoxidil 2% once daily application for 12 months. Comparator 17‐alfa‐estradiol 0.025% once daily application for 12 months.
Outcomes	Assessments (4): at baseline, days 30, 60, and 90 Outcomes of the trial (as reported) Percentage hair in telogen and anagen phase.¹ Adverse events.¹ Hair loss, and hair growth.¹ ¹Denotes outcomes prespecified for this review
Funding source	None declared
Declaration of interest	None declared
Notes	The sample comprised of participants of both genders, and the sequence was generated according to simple randomisation (specific method unreported, but without stratification). The results did not consider gender as a factor or covariate, and the data reported and subsequent analysis is not gender‐specific. We e‐mailed the PI, but received no response. See Table 8
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote (page 22): "un estudio randomizado" and "en forma aleatoria mediante randomización simple en dos grupos" (randomised through simple randomisation). Comment: the trial authors did not report the method used to generate the allocation sequence in sufficient detail to allow a clear assessment of whether it would produce comparable groups.
Allocation concealment (selection bias)	Unclear risk	The method used to conceal the allocation sequence, that is to determine whether intervention allocations could have been foreseen in advance of, or during, enrolment, was not reported. Comment: there was insufficient information to permit a clear judgement of the risk of bias.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote (page 22): "triple ciego" (triple‐blind). Comment: the report did not provide sufficient detail about the measures used to blind study participants and personnel from knowledge of which intervention a participant received, to permit a clear judgement.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote (page 22): "triple ciego" (triple‐blind). Comment: uncertainty with the effectiveness of blinding of outcomes assessors (participants, healthcare providers) during the study. There was insufficient information to permit a clear judgement.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	7/40 (18%) withdrawals/losses to follow‐up: unclear how many from each group. The data analysis was per‐protocol. Comment: although the numbers of dropouts appear balanced between the groups, the percentage of dropouts and subsequent per‐protocol analysis poses an unclear risk of bias.
Selective reporting (reporting bias)	Low risk	The protocol for the study was unavailable, but the trial appears to have reported the prespecified outcomes and those mentioned in the methods section. Comment: we judged this as at a low risk of bias.
Other bias	Low risk	Comment: the study appeared to be free of other forms of bias.