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SYMPTOMS

Hair shedding

Everyday reasons for hair shedding, what to ask your doctor to check, and which nutrients have been studied.

Also described as: hair loss, hair fall, shedding, losing hair, losing my hair, thinning hair, hair thin, balding, bald spot

Common everyday causes

Shedding after a stress, illness or weight loss

A shock to the body (illness, surgery, crash diet, a baby, big stress) pushes many hairs into resting phase; they shed 2–3 months later and regrow over 6–9 months. No test for this itself; check ferritin and thyroid to rule out the others.

Low iron stores

Iron carries oxygen and powers energy production; stores (ferritin) run low well before anemia shows, especially with heavy periods or a plant-based diet. Ask for a ferritin test (with a complete blood count).

Stress load (your stress response on overdrive)

Ongoing stress keeps cortisol and adrenaline up: wired-but-tired, poor sleep, cravings, gut upset, shedding and lower libido. No routine test is reliable (a morning cortisol is only a snapshot).

An underactive thyroid

The thyroid sets your metabolic pace; when it slows, energy, mood, hair, skin and bowels slow too. It is common in women and after pregnancy, and it needs a doctor, not a supplement. Ask for TSH and free T4 (plus TPO antibodies).

Low zinc

Zinc runs immune cells, skin repair and hair growth. Plant-based diets, acid reducers and gut conditions lower it. Ask for a plasma zinc test.

Low vitamin D

Vitamin D supports muscles, bones, mood and immune defenses. Low levels are very common, especially in winter, with darker skin or little sun. Ask for a 25-hydroxy vitamin D test.

If you take certain medicines

GLP-1 medicine: eating less protein and nutrients

GLP-1 medicines cut appetite so much that protein and micronutrients often fall short; fast weight loss also triggers hair shedding. Ask for B12, ferritin and vitamin D tests; aim for 25–30 g of protein per meal.

What’s been studied

• Iron

  For low iron. Only with a lab result that shows it’s needed.

• Vitamin C

  For low iron. Only with a lab result that shows it’s needed.

• L-theanine

  For stress load.

• Rhodiola

  For stress load.

• Magnesium

  For stress load.

• Selenium

  For thyroid. Only with a lab result that shows it’s needed.

• Zinc

  For low zinc.

• Vitamin D3

  For low vitamin D.

• Vitamin K2

  For low vitamin D.

• Vitamin B12

  For GLP-1 medicine.

apiece asks a few quick questions about hair shedding in its quiz to tell these causes apart, and suggests only ingredients studied for the likely ones.

Questions

What can cause hair shedding?

Common everyday reasons include stress shedding, low iron, stress load, thyroid, low zinc. A doctor can help find which applies to you.

What tests can help explain hair shedding?

Ask your doctor about: No test for this itself; check ferritin and thyroid to rule out the others; a ferritin test (with a complete blood count); No routine test is reliable (a morning cortisol is only a snapshot); TSH and free T4 (plus TPO antibodies); a plasma zinc test; a 25-hydroxy vitamin D test.

Which supplements are studied for hair shedding?

Depending on the cause: Iron, Vitamin C, L-theanine, Rhodiola, Magnesium, Selenium, Zinc, Vitamin D3, Vitamin K2, Vitamin B12. Some only make sense with a lab result (for example iron only when ferritin is low).*

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This page is general information, not medical advice. Check with your doctor or pharmacist before starting a supplement, especially if you take medication, are pregnant or nursing, or have a health condition. Updated 2026-10-21.