Most people don’t think of a beauty vitamin as something to mention before blood work. With biotin, you should. High doses can make certain lab tests read wrong, and the FDA has been warning about it since 2017.
Written by Vita Globe Editorial Team | Reviewed against FDA safety communications, NIH guidance and clinical research
Can biotin affect blood test results?
Yes. Many lab tests use biotin as part of their chemistry, and high levels of biotin in your blood can cause falsely high or falsely low results[1][2]. The FDA has specifically warned about troponin tests used to diagnose heart attacks, where biotin can cause a falsely low reading[1][3]. Thyroid tests are also commonly affected[4].
Caveat: Not every test or lab platform is affected, and tests that don’t use biotin chemistry weren’t affected in research[5]. Your lab knows which of its tests are vulnerable, which is why telling them matters.
Sources: FDA safety communication · Colon & Greene, 2018 · FDA troponin assay list · Kummer et al., NEJM 2016 · Verified 2026-09-27
IN THIS ARTICLE
Why does biotin interfere with lab tests?
Many blood tests called immunoassays use a pair of molecules, biotin and streptavidin, that bind very tightly. The test uses that bond to capture and measure things like hormones or heart proteins[2].
When your blood contains a lot of extra biotin from supplements, that free biotin can crowd into the test. Depending on how the test is designed, the result can come out falsely high or falsely low[2][5]. Normal amounts of biotin from food aren’t the concern; high-dose supplements are[6].
Which tests can biotin affect?
The list depends on the test maker and platform, but research and FDA reports have flagged[1][5][6]:
| Test | Why it matters |
|---|---|
| Troponin | Used to diagnose heart attacks. A falsely low result could mean a missed diagnosis. |
| Thyroid tests (TSH, free T4, T3) | Biotin can produce results that look like an overactive thyroid, including Graves’ disease. |
| Other hormones (PTH, prolactin) | Can be pushed falsely high or low. |
| NT-proBNP | A heart-failure marker. |
| 25-hydroxyvitamin D | The standard vitamin D blood test. |
In a JAMA study, six healthy adults took 10 mg (10,000 mcg) of biotin a day for a week. Interference showed up in 9 of 23 biotin-based tests and in none of the tests that didn’t use biotin[5].
What has the FDA said about biotin?
The FDA issued a safety communication in November 2017 and updated it in November 2019[1]. The key points:
- Biotin in dietary supplements, including multivitamins and products marketed for hair, skin and nails, can significantly interfere with some lab tests.
- Some supplements contain up to 650 times the recommended daily intake.
- The FDA remained particularly concerned about troponin tests, because falsely low results can lead to missed heart attack diagnoses. The NIH describes a patient who died after a troponin test gave a falsely low result because of biotin interference[6].
- Consumers should talk to their healthcare providers if they take or are considering biotin.
The FDA also maintains a list of troponin tests that remain subject to biotin interference[3].
Has this actually caused misdiagnoses?
Yes. A 2016 report in the New England Journal of Medicine described patients on high-dose biotin treatment whose thyroid test results mimicked Graves’ disease, an autoimmune thyroid condition[4]. The NIH notes that even a single 10 mg dose has interfered with thyroid tests given within 24 hours[6].
This is especially relevant if you’re taking biotin for hair. Hair shedding is often worked up with thyroid tests, exactly the kind biotin can distort. More on that in Does Biotin Help Hair Growth?
The honest summary
- High-dose biotin can make some lab tests read falsely high or low.
- Troponin (heart) and thyroid tests are the biggest concerns.
- Tell every clinician and lab about biotin, including biotin in multivitamins and hair, skin and nail blends.
- Ask how long to pause biotin before a scheduled test.
What should you do before blood work?
- Make a list of every supplement you take and check each label for biotin, including multivitamins and hair, skin and nail products.
- Tell the person ordering the test and the lab. The FDA advises providers to ask about biotin and pass that information to the lab[1].
- Ask about pausing. How long depends on your dose and the specific test. A 2023 dermatology review cited guidance of at least 8 hours for doses of 5,000–10,000 mcg, and up to 72 hours for very high therapeutic doses[7]. Follow your clinician’s advice.
- In an emergency, such as chest pain, don’t delay care to stop biotin. Just tell the team you take it.
Wondering whether your dose is high? See Is 5,000 mcg of Biotin Safe? and Can You Take Too Much Biotin?
Our option
Vita Globe Biotin 5,000mcg Gummies
Our biotin gummy is a high-dose product, so this article applies to it directly. 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
How long should I stop biotin before a blood test?
It depends on dose and the specific test, so ask your clinician or lab. One review cited at least 8 hours for 5,000–10,000 mcg and up to 72 hours for very high doses[7].
Does biotin affect thyroid tests?
It can. High-dose biotin has produced thyroid results that mimic Graves’ disease[4].
Can biotin affect a pregnancy test?
The FDA’s warning covers a range of biotin-based tests. Tell your provider if you take biotin before any lab test, and ask whether the test they use is affected[1].
Does the biotin in my multivitamin count?
Possibly. The FDA specifically names multivitamins and hair, skin and nail supplements as sources of biotin that can interfere[1]. Check the label amount.
Which troponin tests are affected?
The FDA publishes a list of troponin tests still subject to biotin interference[3]. Your lab can tell you which one it uses.
Sources
- 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).
- Colon PJ, Greene DN. Biotin interference in clinical immunoassays. J Appl Lab Med. 2018;2(6):941-951. doi:10.1373/jalm.2017.024257
- U.S. Food and Drug Administration. Biotin Interference with Troponin Lab Tests – Assays Subject to Biotin Interference. Updated June 21, 2022. fda.gov
- Kummer S, Hermsen D, Distelmaier F. Biotin treatment mimicking Graves’ disease. N Engl J Med. 2016;375(7):704-706. doi:10.1056/NEJMc1602096
- Li D, Radulescu A, Shrestha RT, et al. Association of biotin ingestion with performance of hormone and nonhormone assays in healthy adults. JAMA. 2017;318(12):1150-1160. doi:10.1001/jama.2017.13705
- Office of Dietary Supplements, National Institutes of Health. Biotin: Fact Sheet for Health Professionals. Updated January 10, 2022. ods.od.nih.gov
- 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
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.
