Comment: The quality of evidence is downgraded by study limitations (unclear allocation concealment and blinding).
A Cochrane review [Abstract] 1 included 47 studies with a total of 5 290 subjects. The included trials evaluated a wide range of interventions; 17 studies evaluated minoxidil and 3 studies finasteride. The proportion of participants with clinically significant hair regrowth with minoxidil (1% or 2%, follow-up 24 to 32 weeks) at the end of the study was bigger compared with placebo both as self-rated (26.5% versus 13.9%) and investigator-rated (18.4% versus 7.7%) (table T1, moderate quality evidence). There was no difference in effect between the minoxidil 2% and 5% with the quality of evidence rated moderate to low (4 studies, 1006 participants). There was not a difference in adverse events (table T1).
| Outcome | Relative effect (95% CI) | Risk with placebo | Risk with minoxidil (95% CI) | Number of participants (studies) |
|---|---|---|---|---|
| The proportion of participants with self-rated clinically significant hair regrowth | RR 1.93 (1.51 to 2.47) | 139 / 1000 | 268 / 1000 (209 to 343) | 1148 (6) |
| Proportion of participants with investigator-rated clinically significant hair regrowth | RR 2.35 (1.68 to 3.28) | 77 / 1000 | 181 / 1000 (129 to 253) | 1181 (7) |
| Mean change from baseline in total hair count | −3.25 to 20.4 hairs/cm² | 13.18 hairs/cm²higher (10.92 higher to 15.44 higher) | 1242 (8) | |
| Adverse events | RR 1.24 (0.82 to 1.87) | 88 / 1000 | 109 / 1000 (72 to 164) | 727 (4) |
Finasteride was no more effective than placebo in 3 trials (low quality evidence). Two studies (141 participants) evaluated low-level laser comb therapy compared to a sham device. According to the participants it was not more effective than the sham device. However, there was a difference in favour of low-level laser comb for change from baseline in hair count (MD 17.40, 95% CI 9.74 to 25.06; and MD 17.60, 95% CI 11.97 to 23.23; low quality evidence).
Date of latest search: 7 July 2015
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