All it takes is a glance at the women’s-magazine covers in any grocery store checkout line to see that hair, for us ladies, is supposed to be a crucial part of our style and sex appeal. Whether that notion is true, ridiculous, or somewhere in between, the state of our hair can be hard to ignore when we look in the mirror, which is why even the most level-headed, least superficial of us understandably feel concern at the thought of balding.

Yet each year, more women are facing the serious reality of female hair loss, known as female pattern baldness. According to the American Academy of Dermatology, the condition affects around thirty million women in the United States alone. But what causes this rarely discussed problem? Is it indicative of larger, underlying health issues? To understand it, I learned a little more about how hair grows and what kinds of other disorders can make it fall out.

Interrupted Growth Patterns
Healthy strands usually grow about one-half inch per month. Each hair has a different growing phase, varying from two to six years, after which a strand stops growing and just hangs out for a bit before falling out, which is natural. When hairs fall out, their follicles stay put, sprouting a new strand to continue the cycle. At any time, this means that about 85 percent of our hair is growing while the remainder is resting. Normal hair loss is about 40 to 120 strands per day, but that figure varies depending on hair type (people with darker, thicker hair shed more). While ethnicity plays a role in hair type and density, female pattern balding doesn’t discriminate.

So what causes hairs to fall out without resprouting fresh ones in their place? To understand, we have to look at the processes behind baldness. In both men and women, hormones play a role. Those who are genetically predisposed to balding can blame a type of hormone called androgens for interfering with the growing cycle. Androgens, according to a study published in the Journal of Investigative Dermatology, are produced in large amounts in men’s bodies and small amounts in females’.

For anyone with a genetic proclivity for abnormal hair loss, testosterone comes into contact with hair cells and is converted into a more potent hormone: DHT. This binds the follicle’s cells and builds up as we age. Over time, the buildup causes the follicle to shrink, shortening the hair’s natural rest and growing phases. Eventually, the follicles eventually die all together, resulting in bald patches.

Specifically Female Causes
Male and female balding aren’t caused by the same pattern, which is why it’s now referred to as female pattern hair loss—not alopecia, the broad term for hair loss. The female pattern is distinct because researchers have found that it encompasses many possible causes, in addition to genetics and age. Unsurprisingly, most baldness studies have been performed on male subjects, so we’re only just learning about the unique factors that create this problem in women: enzymes, blockers, and hormone receptors make it an entirely different situation.

Researchers point to the physical pattern in which female hair loss occurs as evidence of its separateness from male balding, say the National Institutes of Health. Hormone and enzyme receptors vary in different areas of the scalp; on women, hair disappears around the top of the head, while men lose it around their temples and on their crowns first. Other than women’s bodies causing a response that causes female balding, it’s possible that other medical issues could be at play, too; a doctor will try to rule out all these factors before diagnosing someone with official female pattern balding. Medical culprits include:

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