The effects of minoxidil, 1% pyrithione zinc and a combination of both on hair density: a randomized controlled trial
R.S. Berger , J.L. Fu*, K.A. Smiles†, C.B. Turner†, B.M. Schnell†, K.M. Werchowski† and K.M. Lammers†
Hill Top Research, Inc., East Brunswick, NJ, U.S.A. *Reed Hartman Research Center, Cincinnati, OH, U.S.A. †The Procter & Gamble Company, Sharon Woods Technical Center, 11511 Reed Hartman Highway, Cincinnati, OH 45241, U.S.A.
Correspondence to Kenneth A.Smiles. E-mail: firstname.lastname@example.org
Copyright 2003 British Association of Dermatologists
male pattern baldness • microscopy • minoxidil • pyrithione zinc • randomized controlled trial
Background Recent studies of antidandruff shampoos or tonics containing antifungal or antibacterial agents produced effects suggestive of a potential hair growth benefit.
Objectives The purpose of this 6-month, 200-patient, randomized, investigator-blinded, parallel-group clinical study was to assess the hair growth benefits of a 1% pyrithione zinc shampoo. The efficacy of a 1% pyrithione zinc shampoo (used daily), was compared with that of a 5% minoxidil topical solution (applied twice daily), a placebo shampoo and a combination of the 1% pyrithione zinc shampoo and the 5% minoxidil topical solution.
Methods Two hundred healthy men between the ages of 18 and 49 years (inclusive) exhibiting Hamilton–Norwood type III vertex or type IV baldness were enrolled. Total hair counts, the primary efficacy measure, were obtained using fibre-optic microscopy and a computer-assisted, manual hair count method. Secondary measures of efficacy included assessments of hair diameter, as well as patient and investigator global assessments of improvement in hair growth. These were based on photographs of the scalp using both midline and vertex views.
Results Hair count results showed a significant (P < 0·05) net increase in total visible hair counts for the 1% pyrithione zinc shampoo, the 5% minoxidil topical solution, and the combination treatment groups relative to the placebo shampoo after 9 weeks of treatment. The relative increase in hair count for the 1% pyrithione zinc shampoo was slightly less than half that for the minoxidil topical solution and was essentially maintained throughout the 26-week treatment period. No advantage was seen in using both the 5% minoxidil topical solution and the 1% pyrithione zinc shampoo. A small increase in hair diameter was observed for the minoxidil-containing treatment groups at week 17. Assessments of global improvements by the patients and investigator generally showed the benefit of 5% minoxidil. The benefit of the 1% pyrithione zinc shampoo used alone tended (P < 0·1) to be apparent only to the investigator.
Conclusions Hair count results show a modest and sustained improvement in hair growth with daily use of a 1% pyrithione zinc shampoo over a 26-week treatment period.
Dont know what-the-hell to make of that study. If pyrithione zinc helps, then it combined with minoxidil should have even more of an effect…surely they dont both work by the same mechanism. Strange study there.