Thinning Hair, Dandruff, Graying, and More: 16 Hair Mysteries Explained

Updated: Jun. 30, 2022

Hair is an important aspect of our appearance, and that can affect self-esteem and identity. So it's best to know all the facts about your follicles.

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Gradually thinning hair

If you notice a gradual reduction in the overall volume of your hair—but you don’t notice an unusual amount of hair fallout—it’s probably androgenic alopecia. Androgenic alopecia is commonly known as male pattern baldness—but it occurs frequently in women as well. It happens when hair follicles on the scalp develop a sensitivity to adrogens, a male hormone. This type of hair loss is largely genetic and is relating to aging, says Anabel Kingsley, renowned trichologist. You’ll probably find that the hair shaft itself becomes thinner too, as follicles are gradually shrinking. Kingsley says this type of hair thinning is the most difficult to treat, but a topical or oral medication can prevent further hair loss. Regrowth is possible, she says, but not in everyone; it simply depends on the person. Changes in your hair can offer subtle clues to other things going on in your body. Here are all the things your hair is trying to tell you about your health.

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Suddenly thinning hair

If you notice a drop in overall hair volume, but it’s not gradual—as in, you see more hair than usual in your shower drain or hair brush—you probably have telogen effluvium, says Kingsley. This type of hair loss is not hereditary. Rather, it can be the result of stress, a thyroid condition, childbirth, a nutritional deficiency, and even the flu. “Hair is an inessential tissue,” says Kingsley—despite it seeming sometimes essential to our self-image. “So whenever there is an internal imbalance, or we’ve been unwell, [our systems] will stop sending essential nutrients to our hair.” If Kingsley suspects telogen effluvian, she’ll usually send her client to a medical professional to address the underlying issue. Mercifully, this telogen effluvian is usually temporary, and most clients see regrowth. Here are more reasons your hair might be falling out.

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Bald patches

It was once thought that temporary bald patches were caused by stress and nerves, but dermatologists now know that isn’t true. This condition, known as alopecia areata, is actually an autoimmune disease, according to the American Academy of Dermatology. It occurs when the immune system literally attacks hair follicles on the scalp. It can happen to hair follicles on the face and other parts of the body, too. Alopecia areata doesn’t discriminate either; it affects about 6.8 million Americans of all ages and races and both sexes. Alopecia areata is treatable, though, though the hair may be absent, your follicles are actually still alive. This means regrowth is always possible, though not guaranteed. Doctors typically treat this type of hair loss with oral or injectable medications.

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About 95 percent of men can blame their thinning hair on male pattern hair loss, according to WebMD. Though it’s exactly the same type of male pattern hair loss that affects women, androgen alopecia presents differently in men. Male pattern baldness is hormonal and hereditary, and it’s caused by “a genetic predisposition to follicle sensitivity to circulating androgens, or male hormones,” says Kingsley. “However, as men naturally have higher levels of androgens, the volume reduction tends to be more severe. The pattern of volume loss is also usually different in men and women. In men, androgenic alopecia starts with a typical bi-temporal recession and thinning of the vertex, which can progress to the point where a man is left with only a ‘horseshoe’ of hair around the scalp from ear-to-ear.” You’ll definitely want to find out how to prevent baldness in men, but once you’re bald, often the only solution is to mask the area where hair has thinned. A new “Hairline Rescue” treatment uses micro-blading—like a semi-permanent tattoo—to recreate the look of missing hair strands stroke by stroke. “It gives the realistic effect of lush, healthy hair,” says Ramon Padilla, founder of EverTrue Microblading Salon in Manhattan. The treatment lasts about 18 months.

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Flaky scalp is typically caused by dandruff, a benign condition that usually results in little more than self-consciousness. But it can be controlled or avoided completely. “Dandruff is simply a less severe form of seborrhoeic dermatitis,” says Kingsley of the dermatological condition. “Both are caused by an overgrowth of Malassezia yeast on the scalp.” Kingsley says dandruff’s biggest culprits are stress and a poor diet, which can weaken the body’s defenses against the yeast. It can flare up if you haven’t shampooed in a while, but it’s not the result of poor hygiene, according to the American Academy of Dermatology. Men and teens tend to develop the condition most often, and it’s notoriously hard to treat. Caucasians and Asians are advised to shampoo daily with an ordinary shampoo and use a specially formulated dandruff shampoo once a week. African Americans are advised to shampoo once a week using a dandruff shampoo. If you have dandruff that does not respond to dandruff shampoo, visit a dermatologist to rule out a more serious condition such as seborrheic dermatitis, psoriasis, eczema, or a fungal infection, all of which require intervention. Here are 11 natural dandruff treatments.

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Fun fact: Human hair is made of keratin, the same substance that comprises animal horns, hooves, claws, and feathers. The hair shaft itself has three layers, according to Kingsley. The medulla is the center, the cortex is the pigment-rich mid-layer, and the cuticle covers and protects the hair shaft. When the cuticle lies flat, hair is shiny and frizz-free. The cuticle is delicate, though, and things like moisture and chemical processing can get inside and lift it. You can tame frizz by smoothing the cuticle layer with conditioners and specially formulated serums. But the best way to ward off frizz is to prevent it. Experts recommend being kind to the cuticle by brushing you hair only when it’s wet, blow-drying just the roots, and avoiding heat styling and processing as much as possible. Don’t miss these additional secret weapons you need to fight frizz.

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Split ends

“Split ends occur when the distal (end) portion of the hair becomes overly weathered and, as a result, ‘splits’ apart,” Kingsley says of this all-too-common hair nuisance. Like frizz, split ends are a sign that the cuticle has been penetrated and the hair shaft weakened. Aggressive treatments like coloring and heat styling are the usual culprits, but using a boar-bristle hairbrush can contribute to the damage, too. So can waiting too long between salon appointments. “You can’t heal split ends—the only cure is to cut them off,” says Kingsley, though hair serums can temporarily “glue” them together in the meantime. Find out if a hair vitamin might help.

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For most people, spotting that first silver hair gleaming in the mirror can be a dreaded moment. But gray hair is a natural part of the aging process, and can begin as early as your twenties. If you do prematurely gray, don’t go blaming your kids! Contrary to urban legends, there’s no strong scientific case for stress or trauma causing gray hair. Genetics and age dictate when your follicles will start to run out of melanin, the pigment that gives your hair its hue. Scientists believe that hair follicles, to some degree, are on a timer. When each follicle reaches a point in its life where its melanin reserves have run dry, the hair returns to its natural state: white. Because each hair goes white in its own time, we get the appearance of “gray” hair. Find out how to go gray gracefully.

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Ringworm of the scalp

Ringworm is a highly contagious fungal infection—and no, it’s not associated with a worm at all. The fungus can live inside things like hair brushes, hats, and bed sheets, and can easily transfer on contact. This particular fungus feed on dead skin, which is essentially what hair is. It proliferates in moisture, so poor hygiene can make a person particularly susceptible. When ringworm affects the scalp, it can be pretty distressing. Its hallmarks are scaly gray or red patches that tend to be itchy, tender or painful spots, and hair breakage at the affected areas. The good news is doctors can help banish ringworm with prescription antifungal medication and medicated shampoos.

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If you notice shorter hairs forming a “halo” on your head, it could signal a regrowth phase. But if you also see jagged edges, too, it might be breakage (a stylist can tell the difference). Hair breakage is exactly what it sounds like, copious strands of hair that have become so damaged, they literally snap off. Breakage is caused by a variety of things, including dryness, heat styling, over-processing, and excessive or incorrect combing and brushing. Even a poor diet and stress can cause breakage, as the hair enters a dormant growth stage under duress. The key here is to be as kind to your coif as possible by washing and styling gently, using conditioner, eating well, and managing stress. Steer clear of tight braids, extensions, and restrictive hair ties if breakage is a problem. These are signs your hair is desperate for nutrients.

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Texture changes

Maybe your strands were pin straight in childhood, but puberty hit and suddenly you were dealing with a head full of curls. Or you had thick, lush locks until you entered your forties, when your ponytail started to feel thinner than usual. Changes in hair texture boil down to hormones, says Kingsley, and how sensitive you are to their fluctuations. For example, pregnant women often have thick, shiny hair. That’s because their rising estrogen prompts hair follicles to stay in the anagen (growth) phase for longer than usual. “When estrogen levels drop and return to normal after giving birth or ending lactation, 50 percent of women experience postpartum hair fall approximately 12 weeks later,” says Kingsley. The steepest decline in estrogen happens during menopause, when hair follicles shrink and hair starts to visibly thin.

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Chicken skin, goose pimples, goosebumps, whatever you call them, you know them when you see them. And you feel them primarily when you’re cold. But why exactly does your skin sometimes get pimply and your hair stand on end? It’s basically a primitive reaction that we haven’t evolved out of yet. Way back when our bodies were covered in full coats of hair, it served us well for our muscles to contract and cause our follicles to protrude; this phenomenon helped provide extra insulation against cold temperatures. Nowadays, we don’t need goosebumps at all.

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Ingrown hairs

Ingrown hairs are at best unsightly and at worst painful. They happen when a hair decides to grow back into the skin—which is why they often occur after shaving or tweezing—and are most common in places like your legs, underarms, and groin. Anywhere you grow hair has the potential to see ingrown hairs, though; that includes your head, especially if you have tightly curled hair. “A good way to help prevent ingrown hairs is to use an exfoliating scalp mask once to twice a week,” says Kingsley, who recommends mild exfoliants that contain betaine salicylate. Elsewhere on the body, it’s a bit easier to help prevent ingrown hairs. Always use a shaving cream or gel and sharp razors—or simply opt for a depilatory cream. A doctor’s intervention is only necessary if ingrown hairs become infected or chronic.

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Artificially lightened hair has a notorious tendency to turn orange or red—making it look “brassy.” That brassiness is actually a chemical reaction called oxidation. The long and the short of it is that, when you color your hair, harsh chemicals like ammonia, peroxide, and bleach work hard to lift the natural pigments out of your hair and replace them with artificial pigments. But it’s rare that all the original pigment comes out; that brassiness is actually the red and orange undertones of naturally occurring melanin coming to the fore. The good news is your stylist can use toners to cool down unwanted warm tones. At home, you can try a purple shampoo, like Clairol’s Shimmer Highlights. Its purple pigments are the perfect counterpart to tone down warm, brassy hues. Don’t miss these tricks to make your hair color last longer.

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They’ve been associated with quirkiness, mischief, and unruliness (just look to your favorite “Little Rascal” Alfalfa), but cowlicks are nothing more than genetic hair-growth patterns. When a patch of hair follicles is arranged to grow hair in a swirling pattern or in the opposite direction of how you’d typically style it, there’s usually little you can do besides go with the flow. Though cowlicks are basically harmless aesthetic phenomenons, scientists have reason to believe there’s a link between these hairy features and a person’s tendency to be left- or right-handed. A recent study even linked the presence of cowlicks to a gene that suppresses cancer. Hoping to grow out a cowlick? This Japanese beauty trick could make your hair grow faster.

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Uncombable hair

Perhaps the oddest and least relatable hair mystery on this list is that of uncombable hair. No, we’re not referring to the bedhead you sport first thing in the morning or the windblown look you get after coming in from a wind storm. Uncombable hair is actually a rare disease that affects the hair shaft. It’s almost impossible for people who live with this disorder to comb their hair flat, and the resulting unkempt look is hard to avoid. Hair of this nature also tends to break easily and it doesn’t have much pigment, so it usually appears straw-colored. Uncombable hair seems to be caused by a recessive gene mutation that becomes apparent pretty early in life. Luckily, it also tends to go away on its own when puberty hits, and that suggests that it may have a hormonal component. If you find that surprising, just check out the worst hair mistakes you can make.