Minoxidil

Minoxidil

Minoxidil is a vasodilator and originally was exclusively used as an oral drug (Loniten®) to treat high blood pressure. It was discovered, however, to have the side effect of hair growth and reversing baldness, and in the 1980s, Upjohn Corporation received FDA approval to market a topical solution that contained 2% minoxidil to be used to treat baldness and hair loss as Rogaine. Minoxidil is applied topically to the scalp, and has been shown to promote hair growth in about 25% of men and women[citation needed], though it may take several months to work. New hair is usually thinner and lighter, like baby hair, and grows mostly on the top of the head, not at the hairline. Its effects may fade with time. Skin irritation is the most commonly reported side effect. Dizziness and increased heart rate are listed side-effects on the UK patient information leaflet.
Objective evidence shows that minoxidil is effective in frontal areas of the scalp, and not just in the vertex area in male-pattern hair loss. At the conclusion of a 48 week study, improvements were seen in the frontal scalp regions of 51 percent of men using 5 percent minoxidil, 42 percent using 2 percent minoxidil, and 13 percent of placebo users. Among these men, moderate to great increases in hair growth were seen in the frontal scalp regions of 19 percent of men using 5 percent minoxidil, 10 percent using 2 percent minoxidil, and 3 percent of placebo users. [1]
The method of action for Minoxidil is not known. It is clearly not just the vasodialating effects which cause hair regrowth, as no other vasodilator has been shown to be effective in treating hair loss.

More than half

More than half

More 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.[1] Since the 1980s, drug therapy has increasingly become a realistic management option for baldness for men and women. Increased understanding of the role of dihydrotestosterone (DHT) in male and female pattern baldness has led to targeted intervention to prevent this hormone from acting on receptors in the scalp. Coupled with chance discoveries and the ever-present lure of a breakthrough involving stem cells and hair multiplication, scientifically proven baldness treatments continue to be an area of research that receives a large amount of funding.

Social, cultural

Social, cultural, or sexual reasons

A female body devoid of bodily hair, combined with luxuriant tresses was a 19th-century theme: Birth of Venus by William-Adolphe Bouguereau, 1879.Hair is normally removed for social and sexual reasons related to the social role of hair in human society. Many cultures have an aesthetic "ideal" amount of hair for males and females. People whose hair violates such standards may experience real or perceived problems with social acceptance.
Many men in Western cultures shave their facial hair, so only a minority of men have a beard, even though fast-growing facial hair must be shaved daily to achieve a clean-shaven or hairless look. Some men shave because they cannot grow a "full" beard (generally defined as an even density from cheeks to neck), because beard color is different from scalp hair color, or because it grows in many directions, making a groomed look difficult. Some men shave because their beards are very coarse, causing itchiness and irritation. Some men grow a beard from time to time to change their appearance.
In many cultures, particularly North American and Western European, it became increasingly common during the 20th century [1] for women to remove some or all of their body hair, due to societal values that consider it unattractive and/or not feminine (see gender role), or as a matter of practising good hygiene. Women may also remove some or all of their pubic hair for aesthetic or sexual reasons. Adult film stars are well known for this practice. Men may also practice this, but not as commonly. In a sexual context, pubic hair removal is done to increase visual exposure of the genitalia and/or facilitate access to the genital area by removing the barrier of hair.
Some women in Western cultures choose not to remove hair from their bodies as an act of defiance against what they believe to be an oppressive ritual. Others choose not to remove hair simply because they have no desire to.
Some men shave their heads, either as a fashion statement, to cover up male pattern baldness, or to attain enhanced cooling of the skull (particularly for people suffering from hyperhidrosis). A much smaller number of women also shave their heads as fashion or political statements.
Some women also shave their heads for cultural or social reasons. In India, tradition requires widows to shave their heads as part of being ostracized, although the practice is considered a rural one and the government is working to end the practice of ostracizing widows.[2]
In art paintings or carvings from ancient times, one can often see women portrayed with no pubic hair: pubic hair was linked to sexual acts and desires in the general mindset, and thus it was deemed improper and impure in a public painting. This may have influenced aesthetic views regarding the matter as well.[3

Hair removal

Hair removal

Hair removal describes any method of removing hair, especially from the human body.
Depilation affects the part of the hair above the surface of the skin. The most common form of depilation is shaving. Another popular option is the use of chemical depilatories, which work by breaking the disulfide bonds that link the protein chains that give hair its strength, making the hair disintegrate. Epilation removal of the entire hair, including the part below the skin and is therefore longer-lasting. Some individuals may use waxing, sugaring, epilation devices, lasers, threading, intense pulsed light or electrology. Hair is also sometimes removed by plucking with tweezers.

Hair color

Hair color

Hair color is the result of pigmentation due to the presence of the chemicals eumelanin and pheomelanin. In general, the more melanin present, the darker the hair color; the less melanin, the lighter the hair color. Black hair predominates outside of Europe. A person's hair color may also change over time and may be more than one color at a time. Considerable differences in color and texture exist between individuals of similar ethnicity, and immigration and global travel have greatly increased the diversity of hair characteristics among many countries.

Head hair

Head hair

Young Girl Fixing her Hair, by Sophie Gengembre AndersonHead hair is a type of hair that is grown on the head (sometimes referring directly to the scalp). The most noticeable part of human hair is the hair on the head, which can grow longer than on most mammals and is more dense than most hair found elsewhere on the body. The average human head has about 100,000 hair follicles. [1] Its absence is termed alopecia, commonly known as baldness. Anthropologists speculate that the functional significance of long head hair may be adornment, a by-product of secondary natural selection once other somatic hair had been lost. Another possibility is that long head hair is a result of Fisherian runaway sexual selection, where long lustrous hair is a visible marker for a healthy individual (with good nutrition, waist length hair—approximately 1 meter or 39 inches long—would take around 84 months, or about 7 years, to grow). Each follicle can grow about 20 individual hairs in a person's lifetime. [2] Average hair loss is about 100 strands a day. The average human scalp measures approximately 770 cm² (120 square inches). These values are also reported by Desmond Morris[4] although it is not clear if these apply to both men and women. Average number of head hairs (Caucasian)

Hair

Hair

Hair is an outgrowth of protein, found only on mammals.[1] It projects from the epidermis, though it grows from hair follicles deep in the dermis. Although many other organisms, especially insects, show filamentous outgrowths, these are not considered "hair". So-called "hairs" (trichomes) are also found on plants. The projections on arthropods, such as insects and spiders are actually insect bristles, composed of a polysaccharide called chitin. The hair of non-human mammal species is commonly referred to as fur. There are varieties of cats, dogs, and mice bred to have little or no visible fur. In some species, hair is absent at certain stages of life.
The main component of hair fiber is keratin. Keratins are proteins: long chains (polymers) of amino acids.

Biological processes

Biological processes

Biological processes and hygieneCare of the hair and care of the scalp skin may appear separate, but are actually intertwined because hair grows from beneath the skin. The living parts of hair (hair follicle, hair root, root sheath, and sebaceous gland) are beneath the skin, while the actual hair shaft which emerges (the cuticle which covers the cortex and medulla) has no living processes. Damage or changes made to the visible hair shaft cannot be repaired by a biological process, though much can be done to manage hair and ensure that the cuticle remains intact. (For more information on the biological processes involved in hair production, see Hair.)
Scalp skin, just as any other skin on the body, must be kept healthy to ensure a healthy body and healthy hair production. If the scalp is not cleaned regularly, by the removal of dead skin cells, toxins released through the skin or external hazards (such as bacteria, viruses, and chemicals) may create a breeding ground for infection. However, not all scalp disorders are a result of bacterial infections. Some arise inexplicably, and often only the symptoms can be treated for management of the condition (example: dandruff). There are also bacteria that can affect the hair itself, but in first world countries, this is much rarer. Head lice is probably the most common hair and scalp ailment world-wide. Head lice can be removed with great attention to detail, and studies show it is not necessarily associated with poor hygiene. (Indeed, even well-to-do households can experience head lice. More recent studies reveal that head lice actually thrive in clean hair.) In this way, hair washing as a term may be a bit misleading, as what is necessary in healthy hair production and maintenance is often simply cleaning the surface of the scalp skin, the way the skin all over the body requires cleaning for good hygiene.
The sebaceous glands in human skin produce sebum, which is composed primarily of fatty acids. Sebum acts to protect hair and skin, and can inhibit the growth of microorganisms on the skin. Sebum contributes to the skin’s slightly acidic natural pH somewhere between 5 and 6.8 on the pH spectrum. This oily substance gives hair moisture and shine as it travels naturally down the hair shaft, and serves as a protective substance preventing the hair from drying out or absorbing excessive amounts of external substances. Sebum is also distributed down the hair shaft “mechanically” by brushing and combing. When sebum is present in excess, the roots of the hair can appear oily, greasy, generally darker than normal, and the hair may stick together.

Hair care

Hair care

Hair care is an overall term for parts of hygiene and cosmetology involving the hair on the human head. Hair care will differ according to one's hair type and according to various processes that can be applied to hair. All hair is not the same; indeed, hair is a manifestation of human diversity.
In this article, 'Hair care' is taken to mean care of hair on the human head, but mention should be made of process and services which impact hair on other parts of the body. This includes men‘s and women’s facial, pubic, and other body hair, which may be dyed, trimmed, shaved, plucked, or otherwise removed with treatments such as waxing, sugaring, and threading. These services are offered in salons, barber shops, and day spas, and products are available commercially for home use Laser hair removal and electrolysis are also available, though these are provided (in the US) by licensed professionals in medical offices or specialty spas.