Hair analysis uses samples of your hair to check for problems, such as metal poisons with lead or mercury. Hair analysis can also be used to check if people are blood relatives. Forensic hair analysis can be done to help identify a criminal by evaluating hair structure and DNA. Hair samples are tested with specific chemicals and looked at under a microscope. Hair is a protein that grows out of hair follicles in the skin. Normally, a hair grows in the hair follicle for many months, stops growing, and falls out. A new hair then grows in the follicle. It takes weeks for a hair sample to show changes in the body, because hair grows slowly. Hair samples do not show recent changes in the body, such as drug use within the past few days. Why It Is Done Hair analysis is used to provide DNA evidence for criminal and paternity cases. For DNA testing, the root of one hair is needed to analyze DNA and to establish a person's genetic makeup. Hair analysis is less commonly used to test for heavy metals in the body, such as lead, mercury, and arsenic. How To Prepare If you have a hair analysis done, the laboratory will give you specific instructions on how to prepare your hair. Hair preparation and the part of your body from which the hair is taken varies. Generally, your hair should be washed and free of any hair care products. You may need to sign a form (consent form) that says you understand the risks of the test and agree to have it done. Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?). How It Is Done Hair analysis is done by collecting a hair sample and sending it to a laboratory: Hair samples are taken from a specific part of the body, such as from the back of the scalp by the neck or from the pubic area. Hair samples are generally collected from the section of the hair closest to the skin. Hair close to the skin or scalp includes the most recent growth, which provides the most accurate information about what has occurred recently in the body. Hair samples are washed in special chemicals before testing. DNA profiles Hair samples for DNA analysis will be gathered by laboratory personnel or law enforcement officials or a forensic examiner. For DNA testing, the hair must include the root. This requires that the hair be plucked, not cut. Heavy metal analysis If you are collecting your own hair sample, follow the instructions given to you by the laboratory. Generally, you will be asked to.

Brown hair is the second most common hair color, with black being the most common.
Brown hair (also referred to as chestnut, cinnamon and dark) varies from light brown to almost black hair. It is characterized by higher levels of the dark pigment eumelanin and lower levels of the pale pigment phaeomelanin. Its strands are thicker than those of fair hair but not as much as those of red hair. People with brown hair are often referred to as brunettes, the feminine form, and brunets (silent t), the masculine term. Brown hair is commonly termed “dark” because of its darker characteristics than that of its blonde or red haired counterparts.

Red hair (also referred to as auburn, ginger or titian) varies from a deep orange-red through burnt orange to bright copper. It is characterized by high levels of the reddish pigment pheomelanin and relatively low levels of the dark pigment eumelanin. People with red hair are often referred to as redheads.[1] Approximately 1% to 2% of the human population has red hair.[2][3] It occurs more frequently (between 2% and 6% of the population) in northern and western Europeans, and their descendants, and at lower frequencies throughout other parts of Europe, Asia and Africa. Red hair appears in people with two copies of a recessive gene on chromosome 16 which causes a change in the MC1R protein. It is associated with fair skin color, freckles, and sensitivity to ultraviolet light, as the mutated MC1R protein is found in the skin and eyes instead of the darker melanin. Cultural reactions have varied from ridicule to admiration; many common stereotypes exist regarding redheads, and they are often portrayed as the “fiery-tempered redhead”. HAIR_HAIR_HAIR.jpg
As well as in humans, red hair can be found in other mammalian species such as orangutans, squirrels, goats, and highland cattle. Red hair or fur can be found in some breeds of dog and cat, and certain species of fox and deer.

Blond is a hair color found in certain people characterized by low levels of the dark pigment eumelanin. The resultant visible hue depends on various factors, but always has some sort of yellowish color, going from the very pale blond caused by a patchy, scarce distribution of pigment, to reddish "strawberry" blond colors or golden brownish blond colors, the latter with more eumelanin.