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.
Scalp skin, just like 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. Head lice is probably the most common hair and scalp ailment worldwide.
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.
One way to distribute the hair’s natural oils through the hair is by brushing with a natural bristle brush. The natural bristles effectively move the oil from the scalp through to the hair’s mid-lengths and ends, nourishing these parts of the hair. Brushing the scalp stimulates the sebaceous gland, which in turn produces more sebum. When sebum and sweat combine on the scalp surface, they help to create the acid mantle, which is the skin’s own protective layer.
Washing hair removes excess sweat and oil, as well as unwanted products from the hair and scalp. Often hair is washed as part of a shower or bathing with shampoo, a specialized surfactant. Shampoos work by applying water and shampoo to the hair. The shampoo breaks the surface tension of the water, allowing the hair to become soaked. This is known as the wetting action. The wetting action is caused by the head of the shampoo molecule attracting the water to the hair shaft. Conversely, the tail of the shampoo molecule is attracted to the grease, dirt and oil on the hair shaft. The physical action of shampooing makes the grease and dirt become an emulsion that is then rinsed away with the water. This is known as the emulsifying action.
Shampoos have a pH of between 4 and 6 and do not contain soap. Soapless shampoos are acidic and therefore closer to the natural pH of hair. Acidic shampoos are the most common type used and maintain or improve the condition of the hair as they don’t swell the hairshaft and don’t strip the natural oils. Conditioners are often used after shampooing to smooth down the cuticle layer of the hair which can become roughened during the physical process of shampooing. There are three main types of conditioners. Anti-oxidant conditioners; which are mainly used in salons after chemical services and prevent creeping oxidation, internal conditioners, which enter into the cortex of the hair and help improve the hair’s internal condition (also known as treatments), and finally external conditioners, or everyday conditioners, which smooth down the cuticle layer making the hair shiny, comb-able and smooth feeling. Conditioners can also provide a physical layer of protection for the hair against physical and environmental damage.
Minerals in water can affect hair.
Calcium causes hair to feel dry and lack shine and volume. It can prevent the proper processing of color. Calcium builds up on the scalp causing flaking of the scalp, giving the appearance of dandruff. Calcium can choke the hair at the mouth of the follicle causing the hair to break off, then coat the scalp, blocking further new hair growth.
Iron can cause water to have a red or rusty hue. Iron leaves hair feeling dry, brittle and weighted down. It causes lack of shine and can cause dark hair to tint darker and blonde hair to turn orange. Iron can inhibit the proper processing of perms and color.
Copper discolors hair causing blonde hair to turn green and dark hair to tint darker. Copper can weigh hair down and cause dryness, and can inhibit the proper processing of perms and color.
Magnesium causes hair to lack shine, feel dry, appear weighted down therefore lacking volume, and can inhibit the proper processing of perms and color.
Silica causes many of the same effects on the hair as calcium. It causes hair to feel dry, lack volume, and can cause dandruff-like symptoms of flaking. Build-up of silica can choke the hair follicle causing hair to fall out.
Lead can cause the hair to feel dry. Lead can prevent the proper processing of perms and color.
Typically, these minerals can be found in ground water usually extracted using a well. The level of calcium that is found naturally from the ground determines the hardness of water. While calcium is the element that determines hardness of water, there are many other elements in well water that affect hair, scalp and skin.
To improve the hair health and further prevent issues with dryness and buildup, people can use a shower head filter that will remove the minerals found in most city waters. However, hard water minerals and the sanitizing agents like Chlorine and Chloramine can also deposit in or on the hair, building up over time. The chemical and mineral content of water varies by geography. Filtering water through very fine mesh cloth may help to remove larger deposits in the water. Many enjoy collecting rain water, although acid rain is an increasing issue in many parts of the world.