It can sometimes feel like your hair is everywhere: in your shower drain, in your brush, on your sheets, on your clothes, on your partner’s clothes — but just because you’re seeing it shed doesn’t necessarily mean you’re experiencing hair loss. You’re supposed to lose about 100 strands every single day, no matter how you wash or style your hair, says Maryanne Senna, MD, a dermatologist and instructor at Harvard Medical School who specializes in hair loss. But when you notice your hair’s not growing back after it sheds, or if you’re losing clumps that seem outside the norm, it’s usually a sign of or reaction to something else (or in many cases, multiple things) happening in your body, she says.
“The majority of the hairs on your head are in the growth phase, and about 10% of your hair is in the resting phase,” Dr. Senna says. “That’s on purpose, because if hairs grew and shed at the same time, we would all go through temporary baldness.” Resting hairs “rest” for three to four months, then gradually shed over time, and this is the stuff you’ll see when you wash and brush.
