Minoxidil (trade names
Rogaine and
Regaine) is a vasodilator
medicationA pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
known for its ability to slow or stop
hair lossBaldness involves the state of lacking hair where it often grows, especially on the head. The most common form of baldness is a progressive hair thinning condition called androgenic alopecia or "male pattern baldness" that occurs in adult male humans and other species...
and promote hair regrowth. It is available
over the counterOver-the-counter drugs are medicines that may be sold to a customer without a prescription from a health care professional, as compared to prescription drugs, which may only be sold to customers possessing a valid prescription...
for treatment of androgenic alopecia, among other
baldness treatmentsMore than half of men are affected by male pattern baldness by age 50, and baldness treatments are estimated to be a US $1 billion per year industry. Since the 1980s, drug therapy has increasingly become a realistic management option for baldness for men and women...
, but measurable changes disappear within months after discontinuation of treatment.
History
Minoxidil was first used exclusively as an oral drug (trade name
Loniten) to treat high blood pressure. It was, however, discovered to have an interesting side-effect: the ability to reverse or slow down the balding process.
Upjohn CorporationThe Upjohn Company was a pharmaceutical manufacturing firm founded in 1886 in Kalamazoo, Michigan by Dr. William E. Upjohn, an 1875 graduate of the University of Michigan medical school. The company was originally formed to make friable pills, which were specifically designed to be easily digested...
produced a
topicalIn medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears....
solution that contained 2% minoxidil to be used to treat baldness and hair loss, under the brand name Rogaine in the United States and Canada, and Regaine in Europe and the Asia-Pacific. Treatments usually include a 5% concentration solution that is designed for men, whereas the 2% concentration solutions are designed for women. The patent on minoxidil expired on February 13, 1996.
In 2007 a new foam-based formulation of 5% minoxidil was shown to be as effective as the liquid-based treatment for male pattern baldness.
While the drug is available in the
United KingdomThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
, it cannot be prescribed on the
NHSThe National Health Service is the name commonly used to refer to the publicly-funded health care services in Great Britain. In England the name National Health Service is used without further qualification whereas the services in Scotland and Wales are known as NHS Scotland and NHS Wales...
, so patients must either buy it over-the-counter or have a private prescription for it.
Results
One study in healthy males aged 18–50 years with
androgenetic alopeciaAndrogenic alopecia is a common form of hair loss in both female and male humans, chimpanzees, and orangutans. In male humans in particular, this condition is also commonly known as male pattern baldness. Hair is lost in a well-defined pattern, beginning above both temples...
(male pattern baldness) found that compared to a baseline of 103 to 106 hairs/cm
2, those who applied of a 5% solution of minoxidil for 32 weeks increased their non-vellus hair counts by an average of 39 hairs/cm
2, in contrast to 5 hairs/cm
2 in subjects who received a
placeboA placebo is a sham medical intervention. In one common placebo procedure, a patient is given an inert sugar pill, told that it may improve his/her condition, but not told that it is in fact inert...
.
Mechanism
The mechanism by which minoxidil promotes hair growth is not fully understood. Minoxidil is a
potassium channelIn the field of cell biology, potassium channels are the most widely distributed type of ion channel and are found in virtually all living organisms. They form potassium-selective pores that span cell membranes...
agonist. Minoxidil is less effective when there is a large area of hair loss. In addition, its effectiveness has largely been demonstrated in younger men (18 to 41 years of age). Minoxidil use is indicated for central (
vertexVertex may refer to:-Mathematics:*Vertex , a corner point of a polygon, polyhedron, tesselation, etc.*Vertex , a node in a graph...
) balding only.
Side-effects
As a drug to combat
hair lossBaldness involves the state of lacking hair where it often grows, especially on the head. The most common form of baldness is a progressive hair thinning condition called androgenic alopecia or "male pattern baldness" that occurs in adult male humans and other species...
, the most common side effect is itchy scalp. Alcohol present in topical preparations may dry the scalp, resulting in
dandruffDandruff is the excessive shedding of dead skin cells from the scalp. Dandruff can also be caused by frequent exposure to extreme heat and cold. As it is normal for skin cells to die and flake off, a small amount of flaking is normal and in fact quite common...
.
Side-effects of
oral minoxidil may include swelling of the face and extremities, rapid and irregular heartbeat, lightheadedness, cardiac lesions, and focal necrosis of the papillary muscle and subendocardial areas of the left ventricle. There have been cases of allergic reactions to minoxidil or the non-active ingredient
propylene glycolPropylene glycol, known also by the systematic name propane-1,2-diol, is an organic compound , with a faintly sweet taste, and is a colorless, nearly odorless, clear, viscous liquid that is hygroscopic and miscible with water, acetone, and chloroform...
, which is found in some forms of topical Rogaine.
Ironically, hair loss is a common side-effect of minoxidil treatment.. Manufacturers note minoxidil induced hair loss is a common side effect and describe the process as 'shedding'. Although this phenomena demonstrates minoxidil is indeed affecting hair follicles, manufacturers offer no guarantee the new hair loss will be replaced with hair growth.
Application
Minoxidil products involve contact with hair strands, which may cause problems with hair styling since minoxidil must be in an alcohol solution. To keep the minoxidil solution from affecting normal hair styling applications, it can be washed out after at least 40 minutes, although this will decrease the hair regrowth effect. For maximum effect, the solution should be in contact with the scalp for four hours before being washed out. If the solution is not a problem, hair styling devices can be used as soon as the minoxidil solution has dried.
Minoxidil solutions are sold under many brand names. Many high priced as well as generic brands of minoxidil regrowth solutions exist and do not differ in their active ingredient or concentration (except differing versions within each brand).
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