Whiting 1992.

Methods	This was a randomised, double‐blind, placebo‐controlled trial Setting Departments of Dermatology and Pediatrics, University of Texas, Dallas, Texas; and the Baylor Hair Research and Treatment Center, Baylor University Medical Center, Dallas, Texas, USA Date of study Unspecified (32‐week duration)
Participants	33 women Mean age (range) = 34 years (20 to 44) Inclusion criteria Good general health; no evidence of cardiac, scalp, systemic, or psychiatric disease. No previous treatment with topical minoxidil solution. Exclusion criteria Pregnancy or risk of pregnancy. A postpartum period < 12 months. Breast‐feeding. Use within the preceding 3 months: hair restorers or systemic drugs, e.g. anticonvulsants, antihypertensives, ß‐blockers, cimetidine, cyclosporine, cyproterone acetate, cytotoxic compounds, diazoxide, oestrogens or progesterones, ketoconazole, spironolactone, steroids, and vasodilators. Randomised 33 participants were randomised (minoxidil group = 17, placebo group = 16) Withdrawals/losses to follow‐up Because of other health problems, relocation, or noncompliance with follow‐up 2 withdrew/were lost to follow‐up in the minoxidil group and 3 in the placebo group Baseline data Mean duration of hair loss 7.25 years (range = 6 months to 25 years). Degree of thinning Ludwig scale (participants by grade and group) Grade I: minoxidil group = 13, placebo group = 9. Grade II: minoxidil group = 4, placebo group = 7.
Interventions	Intervention Minoxidil 2% solution. 1 mL twice daily to the scalp for 32 weeks. Comparator Vehicle. 1 mL twice daily to the scalp for 32 weeks.
Outcomes	Assessment was every 4 weeks. Outcomes (as reported) Hair counts: macro‐photograph pre‐defined tattooed area and count with Quantimet 920 Image Analyzer Cambridge Instrument, Cambridge, MA.¹ Overall growth: a global photograph of the affected area.¹ Regrowth: investigator‐ and participant‐assessed (subjective).¹ Participant‐assessed hair shedding between visits.¹ ¹Denotes outcomes prespecified for this review
Funding source	None declared
Declaration of interest	None declared
Notes	Adverse events were not an outcome, but the trial reported that local side‐effects were not severe, and no participants stopped using the medication because of irritation (page 803)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote (page 801): "randomized". 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 trial authors did not report 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. Comment: there was insufficient information to permit a clear judgement.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote (page 801): "double‐blind". 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	There was insufficient information to permit clear a judgement of the risk of bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	There was a low number (5/33) of dropouts: 2 in the minoxidil group and 3 in the placebo group. Reasons were reported and balanced across groups. The data analysis was per‐protocol. Comment: we judged this as at a low risk of bias.
Selective reporting (reporting bias)	Unclear risk	The study protocol was unavailable. Quote (page 802): "The investigator and patient subjectively evaluated visible hair regrowth." Comment: No data were reported for these participant‐ and investigator‐subjective assessments of hair, only that these "correlated poorly with the actual hair counts in the test area." The primary outcomes for this review were under‐reported, so judged this as at unclear risk of bias.
Other bias	Unclear risk	The potential impact of the wide range in duration (6 months to 25 years) of hair loss at baseline was unclear. Comment: there was insufficient information to permit a clear judgement of the risk of bias.