Losing about 50 to 100 hairs a day is normal. If you're suddenly shedding far more than that, diffusely across the whole scalp, especially when washing or brushing, the likely cause is telogen effluvium. In this condition a stressor pushes many follicles into their resting (telogen) phase at once, and they shed together about two to three months later. Crucially, the follicles themselves stay intact and are not miniaturized.
Distinguishing telogen effluvium from androgenetic alopecia (AGA) matters. Telogen effluvium comes on suddenly and all over, usually with an identifiable trigger two to three months earlier, such as illness, childbirth, surgery, a crash diet, thyroid problems, iron deficiency, a new medication, or severe stress, and it typically self-resolves within about three to six months (up to nine) once the trigger is gone. AGA, by contrast, is gradual and patterned (frontal and crown in men, central part in women) and progresses without treatment.
Low iron (ferritin) is a common contributor, particularly in menstruating women and vegetarians, and low vitamin D, zinc, or inadequate protein and calories can play a role too. However, there is little evidence that supplements help someone who isn't actually deficient, so testing first is the sensible step.
Try the free self-check →Sources: AAD — shedding ↗
FAQ
How many hairs a day is normal to lose?
Roughly 50 to 100 hairs per day falls within the normal range. Shedding well beyond that, evenly across the scalp, can indicate telogen effluvium. Since counting exactly is impractical, it's more realistic to judge by whether the amount on your pillow, in the drain, or on your brush has clearly increased from your baseline.
Why am I suddenly shedding so much?
Sudden, diffuse shedding most often points to telogen effluvium. Look back two to three months for a trigger: a feverish illness, childbirth, surgery, a crash diet, thyroid issues, iron deficiency, a new medication, or major stress. Once the trigger resolves, recovery usually happens gradually over three to six months.
Will supplements help my shedding?
If a deficiency is confirmed, such as low iron, correcting it can help. But there's little evidence that biotin or generic "hair" supplements help people who aren't deficient. Biotin can also distort blood tests like thyroid and cardiac enzymes, so it's wiser to test for a deficiency first than to supplement blindly.
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⚠️ When to see a doctor — don’t self-treat
- Sudden patchy or circular bald spots
- Redness, scaling, pus, pain or itch (possible scarring alopecia — treat urgently)
- Broken hairs or rapid loss
- Loss with body-wide signs (weight loss, fatigue, cycle changes, acne, extra hair)
- Loss right after a new medication
- Any hair loss in a child