Why is my hair falling out?
By Vita · fact-checked against NIH ODS
Vita is Vitaminico's AI nutrition coach. The nutrients below are mapped from the Vitaminico check, and every dose is checked against the NIH Office of Dietary Supplements; these pages have not yet been reviewed by our registered dietitians.
Sudden hair shedding is a symptom, not a diagnosis — low iron, vitamin D, zinc or protein are common contributors, but a blood test is the only way to know.
Likely nutrient gaps
These are the nutrients most often worth looking at first for this — not a diagnosis, just where the Vitaminico check starts. Read any one to see what it does, the best foods, and how much is too much.
Iron
8 mg/dayLow iron stores are the most consistently reported nutritional link to diffuse shedding (telogen effluvium), especially in women, those with heavy periods, and vegetarians/vegans. Ferritin can be low even when hemoglobin is normal, so a low blood count isn't required. Reviews suggest keeping ferritin above roughly 30-40 ng/mL, though the deficiency-without-anemia link is still debated.
Zinc
11 mg/dayDocumented cases show shedding reversing after supplementation in people who are genuinely zinc-deficient. Evidence is inconsistent and routine screening isn't recommended — and importantly, TOO MUCH zinc can itself cause hair loss and block copper, so this is a test-then-treat nutrient, not a blind supplement.
Vitamin D
15 mcg/dayLow vitamin D is associated with several shedding patterns, including telogen effluvium and alopecia areata; in one study alopecia areata patients averaged 17.9 ng/mL versus 30.7 ng/mL in controls. Deficiency is very common, so it's worth checking, but the evidence is associational, not proof that supplements regrow hair.
What to eat
Food first is the safest place to start. Build your plate around a few of these everyday sources of the nutrients above:
- Iron-rich foods paired with vitamin C: lean red meat or a small amount of liver, or for plant eaters lentils/beans/tofu eaten WITH bell peppers, citrus, or strawberries (vitamin C boosts absorption of plant iron)
- Zinc sources: oysters, beef, pumpkin seeds, chickpeas, cashews
- Protein at every meal: eggs, fish, Greek yogurt, tofu, beans, chicken — aim for a palm-sized portion to give hair its building blocks
- Vitamin D from oily fish (salmon, sardines, mackerel), egg yolks, and fortified milk/plant milks; sensible sun exposure also helps
- Omega-3 fats and overall nutrient density: sardines, salmon, walnuts, flax
- A generally varied, adequate-calorie diet — recovery from crash-diet shedding usually needs eating ENOUGH, not just a single 'hair' food
How to confirm it (ask your clinician)
You cannot confirm the cause from symptoms alone — hair shedding has many non-nutritional causes (thyroid disease, genetic/hormonal androgenetic alopecia, autoimmune alopecia areata, postpartum shedding, recent illness or high fever, rapid weight loss, and medications). See a GP or dermatologist and ask for blood work: ferritin plus a full blood count (iron), 25-hydroxy vitamin D, zinc, thyroid (TSH), and B12. Only supplement a nutrient that a test shows is low, and only under guidance — excess selenium, vitamin A, zinc, and vitamin E can THEMSELVES cause hair loss, so more is not better. A food/supplement app can flag likely gaps to discuss, but it cannot diagnose.
Not sure which gap is yours?
The free 2-minute Vitaminico check reads your symptoms across 9 body systems and names your most likely gap — food-first, no pills pushed.
FAQ
Is my hair loss definitely caused by a vitamin deficiency?
No. Shedding is a symptom, not a diagnosis. Common non-nutritional causes include thyroid problems, genetic/hormonal pattern hair loss, autoimmune alopecia areata, childbirth, a recent illness or fever, stress, rapid weight loss, and certain medications. Nutrition is one possible contributor among many — which is why testing matters before you blame (or treat) a deficiency.
Will taking biotin regrow my hair?
Almost certainly not, unless you have a genuine biotin deficiency — which is rare because a normal diet and gut bacteria supply plenty. Reviews found no evidence that biotin helps hair in people who aren't deficient, despite it being the most heavily marketed hair supplement. It can also skew blood test results (the FDA has documented a missed heart-attack diagnosis from biotin interference), so mention any biotin use to your doctor.
Which blood tests should I ask for?
Ferritin plus a full blood count, 25-hydroxy vitamin D, zinc, thyroid-stimulating hormone (TSH), and vitamin B12. For hair, many clinicians aim to keep ferritin above roughly 30-40 ng/mL. Vitamin C is worth eating alongside iron because it improves absorption, but it doesn't usually need testing.
Can taking too many supplements make hair loss worse?
Yes. Excess selenium (over about 400 mcg/day), too much vitamin A (hypervitaminosis A), over-supplementing zinc, and high-dose vitamin E can all trigger or worsen shedding. This is why you should correct a measured deficiency rather than megadose 'hair vitamins' blindly.
I'm vegetarian or vegan — am I at higher risk?
For iron and zinc, yes. Plant (non-heme) iron is absorbed less efficiently, and dietary iron needs are estimated to be about 1.8x higher for those who don't eat meat. Pair iron-rich plants with a vitamin C source, and keep an eye on zinc, B12, and total protein.
Vitaminico for iPhone
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Educational, not medical advice. This page does not diagnose a deficiency or any condition. Symptoms can have many causes, nutritional and otherwise — only a clinician and, where needed, a blood test can confirm a real gap. Talk to your doctor before starting any high-dose supplement.