Most of us can live with a bad hair day, wacky haircut or the occasional gray. The most frustrating, hairy situation for women is hair loss, which is affected by genes from both your parents.QUIZ: How Healthy is Your Hair?Hair loss is far more apparent in men than women. Eighty percent of men experience some baldness. But nearly 40 percent of women experience hair loss after menopause. Women tend to thin out all over, rather than develop the signature male pattern baldness. Hair loss is clearly a big appearance issue for women.Before we learn how you lose your hair, let’s understand how it grows. Hair goes through its own growth cycle, unrelated to seasons or hormones. Your genes largely dictate this random biological process.

The two main phases:

Anagen (active): Root cells divide quickly, pushing the hair out. This phase lasts an average of two to three years.

Telogen (resting): This phase in which the hair follicle is completely at rest lasts roughly 100 days.One possible factor for age-related male-pattern baldness is a person’s androgen level (the “male” hormone that men and women produce). We do know we experience hair loss especially quickly if exposed to dihydrotestosterone (DHT, which comes from the metabolism of testosterone).

Essentially, DHT shrinks hair follicles, making it impossible for healthy hair to grow. Anti-baldness medications sometimes work to inhibit the enzyme that makes DHT. Yet some rare side effects include impotence, decreased libido and breast enlargement.
Age-related baldness isn’t the only reason you can experience the dread of hair loss. Other causes include low iron levels, anemia (low blood count) and recent anesthesia for surgery (it’s the stress of surgery and pressure on the head, not the anesthesia). Other things to think of as contributors—menopause or being postpartum, autoimmune diseases such as lupus, thyroid disease and polycystic ovary syndrome (PCOS).

RELATED RESEARCH: Hair Loss Can Signal Health Problems

By the way, wearing hats does not cause baldness. So long as the hat isn’t restricting circulation to the follicles, it can’t cause hair loss.Rapid hair loss is a sign that you should have a range of tests to evaluate your nutrition, health and hormone levels. Hair loss isn’t just an appearance issue. It’s often a sign that something is off elsewhere in your body.

Inflammation in the scalp from seborrheic dermatitis or too much sun can speed the hair loss. It’s often a hormone issue, particularly with the thyroid gland.It’s common to experience a decline in thyroid hormone (hypothyroidism), where your bodily system slow down. Both scalp hair loss and facial hair growth are signs that a doctor should check your hormone levels.If you’re losing your hair, we recommend having the thyroid-stimulating hormone checked every other year. For others, check it around age 20, then at 35, and then every other year after age 50.Hair loss is sometimes treated with a synthetic (sometimes bioidentical) hormone. Then you’ll need to be rechecked six weeks later to see if the supplemental dose is enough.

DISCUSS: Can I be losing my hair from stress?

For men, not needing to shave can signal a decrease in testosterone. The same goes for women—if you need to shave your legs less often, get checked out.Given that hair loss is such a widespread issue, scientists are constantly testing new therapies. Gene therapy, for example, would involve applying genes involved in hair growth directly to the follicle.Also, researchers are testing chemicals treatments to increase the hair growth cycle. One of the most interesting approaches to “the science of getting hair to grow faster” is the prospect of cloning, where a scientist would clone your hair so it could be donated to those in need.

READ MORE: Stress From Your Job May be Causing Your Hair to Fall Out