Five-year follow-up of men with androgenetic alopecia treated with topical minoxidil.

Journal of the American Academy of Dermatology, 1990;


Five-year follow-up of men with androgenetic alopecia..., by Olsen,
Weiner, Amara, and DeLong.

Topical minoxidil (Rogaine) has been shown to be an effective agent in the treatment of androgenetic alopecia. In a 4-month, placebo-controlled trial, patients treated with 2% and 3% topical minoxidil twice daily showed a statistically significant increase in target area terminal hair counts versus placebo. During the entire 12-month controlled trial, there was almost a twofold increase in target area terminal hairs in those receiving active drug and 24% to 56% of patients had moderate to dense regrowth.

What happens with continued use of topical minoxidil for many years?
We reported that hair regrowth tended to plateau after approximately 1 year of treatment with topical minoxidil with maintenance of this growth after 2 years and 9 months of application twice a day. The purpose of this article is to extend the follow-up in those men who have continued to use topical minoxidil for 4 1/2 to 5 years.

Thirty-one of the 126 men who completed the first study year continued to use topical minoxidil for 4 1/2 to 5 counts were performed...standardized photographs were also taken and evaluated.

RESULTS. [...] Hair regrowth with topical minoxidil peaked at approximately 1 year of treatment with a slight but not statistically significant decrease in 1-year counts seen at the 3-year visit. At 1 year there was a mean increase in nonvellus hairs compared with the baseline count of 273.4 and that at 3 years, 246.2. At 4 1/2 to 5 years a further decrease was noted in the mean nonvellus hair counts, which was was a statistically significant decrease from the 1-year nonvellus hair counts but was still a significant increase over the baseline count (p<0.001). However, some patients receiving long-term treatment with topical minoxidil continued to have an increase in nonvellus target area counts at 4 1/2 to 5 years beyond their 1-year counts (n=9). Similarly, a few subjects, despite continued treatment with topical minoxidil, had nonvellus target area hair counts decrease below baseline (n=4).

Comments: In a nutshell, reading from the charts and graphs which I can't reproduce easily here, after 1 year there was an average of 2.7 times as many nonvellus hairs as at baseline. After 3 years, there was an average of 2.5 times as many nonvellus hairs as at baseline. After 4 1/2 to 5 years, there was an average of 2.3 times as many nonvellus hairs as at baseline. This looks pretty linear: if the loss would continue at this rate (a BIG "if"; see later comment about what might be causing this), then it would take something like *16 years* to drop fully back to baseline values, on average! Even if this were to occur, this is a *long* period of time during which one can enjoy extra hair! Also, note the individual variations; some men had more hair after 5 years than they even had after the initial 1-year growth spurt.

There are several explanations as to why topical minoxidil could be less effective at 5 years than at 1 year. Perhaps this is secondary to tachyphylaxis or an obligatory cycling in hair growth. Topical minoxidil stimulates the growth of epidermal cells in culture and presumably stimulates hair growth by initiating and promoting the anagen phase of these epidermally derived structures. The average duration of anagen in scalp hair is 3 years. Whether topical minoxidil or any other hair growth promoter can prolong anagen or the way in which it affects the anagen/telogen cycling process is unknown."

Duration of Minoxidil Therapy to Yield Maximum Benefit

Koperski et al, in a previous issue of the ARCHIVES, noted a drop in total hair counts between the 12th and 30th month of minoxidil use.
This drop was seen in subjects with average and above-average response. The same protocol was employed at our study center...

Our study group began with 149 subjects, but only 102 completed 12 months of study...only 54 continued into their third year of use, and now, with an average follow-up of 45 months, 27 men continue follow-up. The terminal hair counts taken from a target cirle in the center of the vertex bald spot are presented in the Table.

No. of Terminal Hair Count,
subjects months of Study
0 13 26 45
27 45.7 146.7 214.3 298.4

We have not noted a drop in the average hair count of those individuals continuing to use topical minoxidil solution or in the average hair counts of our two-year plus users who dropped out of the protocol. We did note a drop in the terminal hair count in five men in each group (18.5% of the continuing users and 21.7% of the dropouts), but the magnitude of this change was small. Often, total hair counts (vellus, indeterminate, and
terminal) were continuing to increase.

Our experience has suggested that a continuing increase in terminal hair counts is associated with long-term use of topically applied minoxidil and was seen in approximately 80% of assessable cases.

Robert L. Rietschel, MD
Ochsner Clinic and Alton Ochsner Medical Foundation
New Orleans, LA

Dirk B. Robertson, MD
Emory University School of Medicine
Atlanta, GA

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