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How Aging Affects Your Hair

Location, Location, Location (and Texture!)

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Updated October 22, 2012

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

If your hair has you feeling more like Rumpelstiltskin than Rapunzel these days, it may not be your imagination. Turning gray is just one of the changes your hair may undergo as you age. Shifts in thickness, texture, and where your hair grows (too little in some places, too much in others) can all occur over time.

Hair Biology

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Each shaft of hair is a strand of hard protein or keratin, surrounded by an outer layer of overlapping sheets, like roof shingles, that make up the cuticle. The only living part of a strand of hair is the innermost structure of the hair follicle in skin, which contains some of the fastest-growing cells in the body. Hair aging can involve microscopic, biochemical or hormonal changes that affect the follicle, or environmental factors that cause wear and tear on the hair itself.

Changes in Hair Thickness or Texture

A single hair may live about 4 or 5 years. Given that hair grows, on average, a little less than half an inch (1 cm) per month, hair that is 12 inches (30 cm) in length has seen almost three year’s worth of ultraviolet light, friction from brushing, heat from blow dryers, curling irons, and straighteners, and possible chemical exposure through coloring, perming or straightening. Small wonder that hair wear and tear, or "weathering," results: Cuticle cells can become raised and softened, leaving the hair more prone to breaking and rougher in appearance.

Over time, the follicles themselves may gradually produce thinner, smaller hairs, or none at all. This has been referred to as "senescent alopecia," although it may be simply a natural aging process.

What you can do: Products to counteract the effects of aging on hair make up a multi-billion dollar cosmetic industry. They include humectants, which bind moisture to the cuticle, making it appear smoother, as well as hair conditioners that seal the cuticle, products that protect against UV light, and antioxidants. Since no hair has been alive since it emerged from its follicle, cosmetic fixes tend to work by modifying the appearance of each strand, rather than changing the structure of it. Avoid excessive use of heat on hair by limiting hot tools like curling irons, and keep your dryer 6-12 inches away from your head.

Graying

Hair turns gray when its melanin, or pigment, disappears, though the mechanism behind graying is not well understood. Graying typically begins in Caucasians in the early 30s, and often 10 years later in people with darker skin. Its onset is largely determined by genetics. As dermatology researcher Ralph Trueb writes in his paper, The Aging of Hair: "By 50 years of age, 50% of people have 50% gray hair," regardless of sex and initial hair color. Body hair (eyebrows, pubic and chest hair) usually grays much later than hair on the scalp.

One theory about the cause of graying chalks it up to oxidative stress, one of the major theories of aging. This is a condition created when an excess of free radicals are produced as new hairs are formed, which subsequently damages the pigment-creating cellular structures within the follicle. This process may also explain why many people notice their hair becomes coarser and tougher to manage as it grays, since the cells that create melanin are closely connected to the ones that build the keratin hair shaft.

What you can do: If letting your hair go "au naturel" doesn’t appeal, you have a variety of coloring options. Reverse highlights put streaks of darker color back into gray hair. Temporary tints are not absorbed by the cuticle so are easily washed out. Semi-permanent colors can last 6-10 shampoos, as they are made up of small molecules that penetrate the hair cuticle. Permanent dyes work by creating colored molecules within the hair shaft, and therefore withstand repeated shampoos.

Not Enough Hair (Baldness)

For many men -- whether hair loss is known by its scientific name, androgenetic alopecia, or simply as male-pattern baldness -- it’s unwelcome news. Typically, hair is lost at the top of the head or at the temples; by age 60, two-thirds of males have significant hair loss. It is believed that in these men, certain hair follicles are predisposed to produce smaller and less-visible (vellus) hairs over time, as a result of hormonal changes. Smoking may also play a role in male-pattern baldness.

Women may experience "female-pattern" baldness as they age, resulting in thinning hair and visible scalp. It may be due to genetics, shifting levels in male hormones (androgens), vitamin deficiencies or certain health conditions.

What you can do: Currently, there is no cure for baldness. Available drug treatments aim to stimulate the growth of new, more visible hair, and include topical minoxidil (Rogaine) and Finesteride, which is taken orally. For women, the only treatment approved by the U.S. Food and Drug Administration is minoxidil.

Hair transplants involve grafting tiny segments or plugs of healthy scalp from where hair is thicker to a balding area. This can be an expensive solution requiring many treatments, but the results are often permanent.

Too Much Hair (Hirsutism)

Hirsutism is hair on a woman's body in areas usually associated with males: on the face, neck, chest or thighs. It can be due to genetics, aging, or medications.

Though hirsutism is often a harmless condition, it can be embarrassing to women with it. In rare cases, it can be a sign of a tumor in the adrenal gland or ovary.

What you can do: If temporary solutions like tweezing, waxing, and depilatories aren't working for you, see your doctor. More involved hair removal techniques include laser therapy and electrolysis.

Sources:

Medline Plus. "Aging Changes in Hair and Nails." U.S. National Library of Medicine. NIH Public Information Sheet. Accessed Jan.2, 2012.http://www.nlm.nih.gov/medlineplus/ency/article/004005.htm

Medline Plus. "Female pattern baldness." U.S. National Library of Medicine. NIH Public Information Sheet. Accessed January 3, 2012.http://www.nlm.nih.gov/medlineplus/ency/article/001173.htm

Ralph M. Trueb. "Aging of Hair." Journal of Cosmetic Dermatology. Volume 4, Issue 2, pages 60-72, June 2005.

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