Telogen effluvium, explained: why hair sheds after a shock and when it grows back

What telogen effluvium is

Every hair on your scalp cycles through growing, resting and shedding. Cleveland Clinic says 80% to 90% of follicles are in the growing (anagen) phase at any time. The rest are transitioning or resting (telogen) before the hair falls out and a new one starts.

Telogen effluvium happens when a shock to the system pushes a large number of growing hairs into the resting phase at the same time. DermNet, a dermatology reference from New Zealand, says that after a shock as many as 70% of growing hairs can switch to resting, which reverses the usual ratio.

Those hairs don't fall out right away. They rest first, and then new hairs growing underneath push them out. That's why the shedding shows up months after the event, and why DermNet calls the hair fall "paradoxically" a sign of regrowth.

How much shedding is normal?

The AAD says it's normal to shed 50 to 100 hairs a day. With telogen effluvium, Cleveland Clinic says you may lose up to 300 a day.

You'll often notice it in the shower drain, on your brush, or on your pillow. Cleveland Clinic says it usually affects the whole scalp but is most noticeable on top, and it usually doesn't affect your hairline or cause total baldness.

Common triggers

The AAD lists these stressors as common causes of excessive shedding:

• Losing 20 pounds or more
• Giving birth
• A lot of stress, such as caring for a sick loved one, a divorce or losing a job
• A high fever, or recovering from an illness that included one
• Having an operation
• Stopping birth control pills

DermNet adds a few more: an accident, a nutritional deficiency such as low iron, an unusual diet, some medicines, thyroid problems, jet lag from overseas travel, and some scalp conditions.

Telogen effluvium and GLP-1 medicines

Shedding after starting a GLP-1 medicine like Ozempic, Wegovy or Zepbound is a common worry. The AAD says dermatologists believe this hair loss is caused by the sudden weight loss people go through on these drugs, which fits the telogen effluvium pattern. It also says researchers need more information to know for sure, and that eating less may leave your body short on the protein and nutrients hair needs.

AAD dermatologists suggest that people prone to hair loss lose weight slowly on these medicines. Our GLP-1 hair loss guide covers the timing in more detail.

When shedding is tied to eating less or losing weight quickly, steady meals are part of the picture. Olive is a health companion that checks in with you every day, looks at what you eat, and helps you build small habits that actually hold. It doesn't diagnose or treat anything, so hair loss itself is a question for a dermatologist.

How long it lasts

The timeline is predictable, which is reassuring:

For new parents, the AAD says shedding often starts about two months after giving birth and peaks about four months after.

If the stressor doesn't go away, the AAD says shedding can last longer. DermNet describes a chronic form that tends to affect otherwise healthy women ages 30 to 60, sometimes with no clear trigger.

Is it shedding or hair loss?

The AAD draws a line between the two:

• Shedding (telogen effluvium): Hair falls out after a stressor, and it grows back once the body readjusts.
• Hair loss (anagen effluvium): Something stops the hair from growing. Causes include hereditary hair loss, an overactive immune system, some drugs and treatments, tight hairstyles and harsh hair products. Hair won't grow until the cause stops.

Cleveland Clinic notes that telogen effluvium sometimes looks like male or female pattern hair loss, but it's sudden and heavy, while pattern hair loss is a slow thinning. DermNet adds that repeated bouts of telogen effluvium can sometimes turn into female pattern hair loss, which is one reason to get a diagnosis if it keeps happening.

What helps

Telogen effluvium usually corrects itself. DermNet calls it "self-correcting" and says regrowth usually happens once the trigger is gone. Cleveland Clinic says most cases resolve without treatment within six to eight months after the cause is addressed.

That doesn't mean you have to do nothing. DermNet and Cleveland Clinic suggest:

• Find and address the trigger. If it's an illness, recovery comes first. If it's fast weight loss, a slower pace may help.
• Eat enough. DermNet recommends a nutritious diet with plenty of protein, fruit and vegetables.
• Get checked for underlying causes. DermNet says to correct any problems with thyroid function, iron, vitamin B12 or folic acid. These need blood tests, so ask your doctor rather than guessing with supplements.
• Handle hair gently. DermNet advises avoiding over-vigorous combing and brushing. Our guide to shampoo for thinning hair covers a gentle wash routine.
• Ask about treatment if it's affecting you. Telogen effluvium often needs no treatment, but Cleveland Clinic lists over-the-counter minoxidil applied to the scalp among common options, and says hairstyles, wigs or weaves can help hide thinning while it grows back. Ask a dermatologist whether treatment makes sense for you.

DermNet also says the emotional side of hair loss shouldn't be ignored. Shedding can be upsetting even when it's temporary.

When to see a dermatologist

See a board-certified dermatologist if:

• Shedding goes on longer than the usual few months, or keeps coming back.
• Hair is falling out in patches, or your part is widening.
• Your scalp is itchy, scaly, red or painful.
• You can't link the shedding to any trigger.
• You think a medicine, a thyroid problem or low iron could be involved.

Frequently asked questions

What causes telogen effluvium?

A shock to the body, such as a high fever, surgery, childbirth, major stress, stopping birth control pills or losing 20 pounds or more. It pushes many growing hairs into their resting phase at once.

How long does telogen effluvium last?

Cleveland Clinic says the shedding usually lasts three to six months. The AAD says hair tends to regain its normal fullness within six to nine months.

Does hair grow back after telogen effluvium?

Yes, in most cases. DermNet describes it as a non-scarring type of hair loss, and regrowth usually follows once the trigger is gone. Recovery may be incomplete in some cases, so see a dermatologist if it isn't.

Can telogen effluvium cause baldness?

No. Cleveland Clinic says it usually doesn't affect the hairline or cause total baldness.

Can a GLP-1 cause telogen effluvium?

The AAD says dermatologists believe hair loss on GLP-1 drugs is caused by the sudden weight loss, which is a known trigger for telogen effluvium. Researchers are still studying it.

Should I take supplements for telogen effluvium?

Ask your doctor first. DermNet says to correct a deficiency in iron, vitamin B12 or folic acid if you have one, which takes a blood test to find.

Steady habits while your hair recovers

Shedding settles as your body readjusts, and steady meals help that along. Olive checks in with you every day and notices what's keeping your body stuck.

If steady habits haven't moved stubborn weight, Olive's Protocol is one option to look into. Prescriptions are only written after a medical consultation with a licensed provider. Not everyone qualifies.

See how Olive works →

This guide is general information, not medical advice. Talk with a board-certified dermatologist about your own hair, and don't start, stop or change any medicine or supplement without your doctor.