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Ingredient guide

Best time to take biotin

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

None of our sources sets a best time of day for biotin, and the body absorbs nearly all the free biotin in a supplement whenever it is taken. The timing that matters is around blood tests: one levothyroxine label says to stop biotin at least 2 days before thyroid testing.1,2

Key facts

  • Free biotin is absorbed almost completely, even at doses as high as 20 mg a day.1
  • Raw egg white is the one food our sources say blocks biotin: its avidin binds it, and cooking inactivates it.1
  • The amount of biotin that upsets a test differs from one test and manufacturer to another.3
  • Biotin clears from the blood fairly quickly, which is why pausing before a test can work.3

Morning or night

The NIH fact sheets and the studies on this page give no reason to prefer morning or evening. What they do establish is that the body takes up nearly all the free biotin in a supplement, so the hour you choose is unlikely to change how much you absorb.1

Choose a time you will remember. If your biotin comes inside a multivitamin or B complex, the directions on that product apply to the whole tablet, not to the biotin alone.4

With or without food

Our sources describe no difference between taking biotin with a meal or on an empty stomach. The one food that does matter is raw egg white, because its avidin binds biotin tightly. Cooked eggs are not a problem.1

Most biotin in food is bound to protein. Digestion releases it before the small intestine absorbs it.1

Timing around blood tests

A levothyroxine label tells people who take the medicine to stop biotin and biotin-containing supplements at least 2 days before thyroid blood tests.2

Biotin leaves the blood relatively quickly, so when a lab suspects interference it can test a fresh sample taken after a pause.3

For other tests our sources give no set waiting time, and the biotin level that causes trouble varies by test and by manufacturer. Ask the doctor who orders the test, or the lab, how long to pause, and say how much you take.3

  • Before a scheduled blood draw, tell the person ordering it that you take biotin5
  • If you are told to pause, count every product with biotin, including multivitamins and prenatal vitamins5
  • In an emergency, tell the care team you take biotin, because troponin tests used in heart emergencies can read falsely low1,6

Timing around medicines

If you take levothyroxine, its label addresses biotin because of thyroid testing. Ask your pharmacist how to fit biotin around your medicine and your test schedule rather than working it out alone.2

Questions people ask

Can I take biotin on an empty stomach?

Yes, as far as our sources show. Free biotin is absorbed almost completely, and no source describes a difference with or without food.1

When should I take a 10,000 mcg biotin supplement?

The time of day matters less than the dose. At 10 mg a day, studies have found lab test errors within a week, so plan around blood tests and tell your doctor and the lab that you take it.5,7

Should I stop biotin before a blood test?

Ask your doctor and the lab first. For thyroid tests, a levothyroxine label says to stop biotin at least 2 days before. For other tests, ask how long, because it depends on the test and on how much you take.2,3

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Sources

  1. National Institutes of Health, Office of Dietary Supplements. Biotin: Fact Sheet for Health Professionals. Updated January 10, 2022. Opened 2026-10-07.
  2. Levothyroxine sodium tablets: prescribing information (Cardinal Health 107, LLC). DailyMed, U.S. National Library of Medicine. Published September 24, 2026. Opened 2026-10-07.
  3. Li D, Ferguson A, Cervinski MA, Lynch KL, Kyle PB. AACC Guidance Document on Biotin Interference in Laboratory Tests. J Appl Lab Med. 2020;5(3):575-587. Opened 2026-10-07.
  4. National Institutes of Health, Office of Dietary Supplements. Biotin: Fact Sheet for Consumers. Updated January 15, 2021. Opened 2026-10-07.
  5. U.S. Food and Drug Administration. Testing for Biotin Interference in In Vitro Diagnostic Devices: Guidance for Industry. October 2020. Opened 2026-10-07.
  6. U.S. Food and Drug Administration. Biotin Interference with Troponin Lab Tests: Assays Subject to Biotin Interference. Content current as of June 21, 2022. Opened 2026-10-07.
  7. 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. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.