To answer this question, we have to go back to the basics of the
cycle of hair growth, resting and shedding. When you are born, there are
more than one million hair follicles on your head with
one-hundred-thousand on the scalp. That's a lot of hair! The number does
not change over your lifetime but, as the head grows, the follicles are
spread out more. Each hair grows about 6 inches a year but, randomly,
the hairs are in different stages. The active period of growth is called
anagen where the cells divide and form new growth over a period of
between two and six years. The hair then goes into the catagen stage. At
any one time, about 3% of all your scalp hair is in a transitional
state for about three weeks. The final stage is telogen. About 7% of all
your scalp hair rests for about three months. Towards the end of this
stage, between 25 and 100 hairs are shed each day.
From this you will understand the problem of an "immediate" halt in
any part of this process. We are talking about one-hundred-thousand
hairs and 90% of those hairs are growing. To ensure the coverage of the
head remains even, the distribution of the 10% that will slowly
transition and fall out is entirely random. Thus, when everything is
working properly, only a tiny percentage of hair is falling from each
part of the scalp on any given day. If you are diagnosed with male
pattern baldness, the distribution process has broken down and more hair
is lost from particular parts of the scalp, thereby forming the
distinctive pattern. The effect of the drug is to move the body's
chemistry back in time and trigger the more random process of selecting
hairs for the catagen and telogen stages. This is not something that can
happen immediately. It takes time to change the body's chemistry.
Indeed, if you were to try accelerating the process and took too much of
the active ingredients, there would be no change to the process of hair
growth and shedding, but there could be quite serious effects on other
parts of the body (in animal tests, rats and mice die).
In the clinical trials and all experience following licensing by the
FDA, there's no visible reaction for at least three months after
starting treatment with Propecia.
This is not to say the drug is inactive for the initial period of time.
But to warn you there can be significant delays before you see any
results. It's not uncommon for there to be no obvious reaction for six
months. Some men wait for a year before seeing a change. This is a
treatment regime that requires patience. Do not believe any drug or
product manufacturer who attempts to persuade you that parting with your
money will produce instant results. This is a scam. Propecia works
slowly and steadily to reduce the amount of dihydrotestosterone. It's
not a scam.