Five-year follow-up of men with
androgenetic alopecia treated with topical minoxidil.
Journal of the American Academy of
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 years...hair 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
Torna a minoxidil