The desire to treat hair loss disorders leads to the understanding of the
mechanisms involved in the Minoxidil’s crucial involvement in the
stimulation of hair re-growth. Consequently, this line of research also
leads to the understanding of the biology of hair growth. Histological inspection
on primates showed that Minoxidil treatment causes proportional increase
in anagen follicles, a decrease in the telogen follicles, and an increase
in the size of the hair follicle. However, the only noted effect of Minoxidil
treatment in humans is its role in the human hair cycle, although the possibility
of Minoxidil increasing the hair diameter is currently being studied.
Minoxidil does not display hormonal or immunosuppressant effects when used
as a treatment drug in male pattern baldness. Application of Minoxidil
in plucked anagen hair bulbs showed a significant increase in the proliferation
index when cells were counted and measured by a flow cytometer. This result
is noted in both in vitro and in vivo studies where Minoxidil exhibits a
direct mitogenic effect on epidermal cells.
FDA approved 2% topical Minoxidil (Rogain) in 1988 where over-the-counter
products became available in the market eight years later. 5% topical Minoxidil
(Rogain Extra Strength) was approved and went into the market as over-the-counter
drug in 1998. An astounding increase in hair growth was observed in clinical
experiments after 6-8 weeks of Minoxidil treatment, peaking in the hair
count and hair weight at 12-16 weeks. This was not caused by the reversal
of the follicular miniaturization process which led scientists to believe
that Minoxidil triggered follicles in the latent part of telogen into anagen.
Clinical trials of the efficacy of topical Minoxidil in men
There is no question about the effectiveness of using Minoxidil in treating
androgenic alopecia in both men and women. However the histological studies’ results
suggest that Minoxidil treatment is less conclusive on humans than on animals.
- Olsen and colleagues studied 2294 men with Hamilton III to VI patterns
of male baldness characterized by significant frontal and vertex hair loss.
Patients between ages 18 and 50 were randomly subjected to 1ml of 2% or
3% topical Minoxidil versus placebo twice a day for 4months and then the
placebo group was changed to active drug. The terminal and vellus hair were
counted directly from the target areas located in the mid-vertex region,
the area where greatest hair loss were noted in previous researches. Olsen
and colleagues were able to highlight the significance of treatment of 2%
Minoxidil in increasing the terminal hair counts at the mean target area
although the development was noted in 4-6 months.
- Studies on two randomized double-blind placebo controlled set-up evaluating
5% Minoxidil topical solution versus 2% Minoxidil solution were done.
It was found that the 5% concentration was effective in men under the
18-49 with mild to moderate vertex hair loss. After 48 weeks of twice-a-day
application of 5% Minoxidil, the following results was taken: 57%
of 139 patients had re-growth when 5% Minoxidil was applied; 41% of 142
had hair re-growth with 2% Minoxidil topical solution; and 23% of
exhibited the same results on the placebo-treated group. The quality
of re-growth was mild to moderate in most individuals, while those using
5% formulation showed greater improvement. Peak hair counts were already
noted at 6 weeks on both concentrations, although hair counts and
the patients’ rating
of scalp coverage were higher with 5% Minoxidil.
- Greater improvements
were seen for the 5% Minoxidil topical solution on a study of 36 men
ages 18 to 40 years old based on the hair weight. Although,
the study was conducted on smaller sample sizes, it has been treated as
statistically significant because it the study found that target area
hair-weights increased by 35% for 5% Minoxidil compared to the increase
of 25% in 2%
Minoxidil. Untreated and placebo-controlled groups lost 6% in hair weight
- The evaluations of Price and colleagues on four groups of nine
men with pattern baldness, three of which apply either 2% Minoxidil
or 5% Minoxidil
while the fourth group received no treatment, showed that subjects receiving
5% Minoxidil had faster response in terms of increased hair weight and
number as opposed to those patients receiving 2% topical Minoxidil. The
a similar percentage increase in growth at the 96th week. Also, it was
duly noted that whatever hair was regained in the period of 3-4 months
when the treatment of 2% Minoxidil was discontinued, indicating that Minoxidil
treatment must be continuous to ensure effectivity.
- There are no notable
changes on the cardiovascular activities of the patients using 2% and
5% Minoxidil compared with the control group in a
period of one year.
Clinical Use in male pattern hair loss
Apart from Minoxidil, there is no drug that is seen to prevent further
hair loss in male pattern baldness. 5-year term usage of Rogaine for
twice a day has shown positive results despite continuous shedding over
the first several month of the treatment as anagen is induced and telogen
hairs are shed. The hair counts remained above baseline. Lesser response
on hair re-growth was noted on 2% Minoxidil if it is used less than twice