Biotin deficiency gets blamed for a lot of hair and nail problems. In reality, it’s uncommon in people eating a normal diet. When it does happen, though, it has a recognizable pattern.
Written by Vita Globe Editorial Team | Reviewed against NIH guidance and peer-reviewed research
What are the signs of biotin deficiency?
Signs usually appear gradually and can include thinning hair (sometimes progressing to loss of all body hair), a scaly red rash around the eyes, nose and mouth, brittle nails, and neurological symptoms such as depression, lethargy and tingling[1]. It’s uncommon in people who eat a varied diet, but higher-risk groups include people with biotinidase deficiency, chronic alcohol exposure, pregnancy, and long-term anticonvulsant use[1].
Caveat: These signs overlap with many other conditions. Thinning hair or brittle nails alone don’t mean you’re low in biotin.
Sources: NIH ODS · Verified 2026-09-27
IN THIS ARTICLE
What are the signs of low biotin?
The NIH lists these signs, which tend to develop gradually[1]:
| Area | Signs |
|---|---|
| Hair | Thinning hair, which can progress to loss of all body hair |
| Skin and eyes | Scaly, red rash around body openings such as the eyes, nose and mouth; conjunctivitis |
| Nails | Brittle nails |
| Nervous system | Depression, lethargy, hallucinations, and numbness and tingling in the hands and feet |
| Other | Skin infections, seizures, and acid buildup in the blood and urine (ketolactic acidosis and aciduria) |
These happen because biotin is needed for five carboxylase enzymes that help process fats, carbohydrates and amino acids. Because those enzymes are involved throughout metabolism, that helps explain why deficiency can affect so many parts of the body at once[2].
Who is most at risk of biotin deficiency?
Most people get enough biotin from food: average Western intakes are estimated at 35–70 mcg a day against an adult adequate intake of 30 mcg[1]. The NIH highlights these higher-risk groups[1]:
- Biotinidase deficiency. A rare inherited disorder in which the body can’t recycle biotin properly. Newborns in the U.S. and many other countries are screened for it.
- Chronic alcohol exposure. Alcohol inhibits biotin absorption.
- Pregnancy and breastfeeding. At least a third of pregnant women develop marginal biotin deficiency despite normal intakes.
- Long-term anticonvulsant use. Some seizure medications lower biotin levels.
Two other situations come up. Eating lots of raw egg whites over time can cause deficiency, because a protein in raw whites (avidin) binds biotin. Cooking inactivates it[1]. And a 2023 dermatology review notes biotin depletion can occur with prolonged oral antibiotics and with isotretinoin[3].
Is my hair loss a sign of biotin deficiency?
Maybe, but probably not on its own. In one study of 541 women who came to a clinic complaining of hair loss, 38% had low serum biotin[4]. That’s a notable number, but it describes a selected group, not the general population, and the author cautioned against giving biotin to everyone without first checking levels and ruling out other causes[4].
Hair shedding has many common causes, including iron deficiency, thyroid issues, hormonal changes, stress and illness. For what biotin can and can’t do for hair, see Does Biotin Help Hair Growth?
The honest summary
- Biotin deficiency is uncommon in people who eat a varied diet.
- Classic signs: thinning hair, a scaly red rash around the face, brittle nails and neurological symptoms.
- Higher-risk groups include people who are pregnant, drink heavily, take certain anticonvulsants or have biotinidase deficiency.
- Don’t self-diagnose from hair or nails alone. See a clinician.
How is biotin deficiency diagnosed?
It’s trickier than a single blood test. According to the NIH, blood levels of biotin aren’t good indicators of marginal deficiency. Low urinary biotin excretion and high urinary levels of a compound called 3-hydroxyisovaleric acid are better markers[1]. In practice, clinicians look at symptoms, risk factors and response to treatment, and may order specific tests.
One irony: if you’re already taking a high-dose biotin supplement, it can interfere with many other lab tests, including thyroid tests often ordered to investigate hair loss. The FDA has warned about this, including for troponin heart tests[5]. Read Biotin and Lab Tests before your appointment.
What should you do if you think you’re low?
- Talk to a clinician, especially if you’re pregnant, have a condition or take medications that affect biotin.
- Eat biotin-rich foods such as cooked eggs, salmon, beef liver, sunflower seeds and sweet potatoes[1].
- Don’t megadose on a hunch. More isn’t necessarily better, and your clinician can advise on dose; see How Much Biotin Should You Take?
For a broader look at what biotin does in the body, see What Is Biotin Good For?
Our option
Vita Globe Biotin 5,000mcg Gummies
If your clinician suggests a biotin supplement, our standalone gummy is one option. A two-gummy serving provides 5,000 mcg of biotin in a strawberry-flavored gummy that is vegan, gluten-free and non-GMO, 40 gummies per bottle. Like every Vita Globe product, it is tested by an independent third-party lab. If you have blood work coming up, tell your clinician and the lab that you take it.
Frequently asked questions
What happens when your biotin is low?
Hair thinning, a scaly red rash around the eyes, nose and mouth, brittle nails and neurological symptoms can develop over time[1].
How common is biotin deficiency?
Uncommon in people eating a varied diet, since typical intakes exceed the adequate intake[1].
Can a blood test show biotin deficiency?
Blood biotin isn’t a good indicator of marginal deficiency; urine-based markers are more informative, per the NIH[1].
Does pregnancy cause biotin deficiency?
At least a third of pregnant women develop marginal biotin deficiency despite normal intakes, per the NIH[1]. Talk to your prenatal care provider.
Do raw eggs cause biotin deficiency?
Eating lots of raw egg whites over time can, because avidin binds biotin. Cooking inactivates avidin[1].
Sources
- Office of Dietary Supplements, National Institutes of Health. Biotin: Fact Sheet for Health Professionals. Updated January 10, 2022. ods.od.nih.gov
- Zempleni J, Wijeratne SSK, Hassan YI. Biotin. BioFactors. 2009;35(1):36-46. doi:10.1002/biof.8
- Farris PK, Engelman D, Day D, Hazan A, Raymond I. Natural hair supplements: trends and myths untangled. J Clin Aesthet Dermatol. 2023;16(1 Suppl 1):S4-S11. jcadonline.com
- Trüeb RM. Serum biotin levels in women complaining of hair loss. Int J Trichology. 2016;8(2):73-77. doi:10.4103/0974-7753.188040
- U.S. Food and Drug Administration. UPDATE: The FDA Warns that Biotin May Interfere with Lab Tests: FDA Safety Communication. November 5, 2019 (original communication November 28, 2017).
About the Vita Globe Editorial Team
The Vita Globe Editorial Team researches and writes our wellness content, working from peer-reviewed research, systematic reviews and guidance from bodies such as the NIH and the FDA. We cite our sources inline and update articles when the evidence changes.
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 article is for informational purposes only and is not a substitute for medical advice. Talk to your healthcare provider before starting any new supplement, particularly if you are pregnant, nursing, taking medication, or caring for a child.
