Biotin and blood tests: what to tell your doctor
High-dose biotin is common in hair, skin and nails supplements. It can also skew some laboratory tests, so your doctor and lab need to know you take it.
Many lab tests use a biotin-based chemistry. Biotin in your blood from a supplement can make some results read falsely high or low. Tell your doctor and the lab you take biotin before any blood test, and follow their instructions about pausing it.
Why biotin affects lab results
Many immunoassays, the tests used to measure hormones and other markers, use biotin and streptavidin to capture what they measure. When blood contains a lot of biotin from a supplement, it can compete in that reaction. Depending on how the test is built, results may come out falsely high or falsely low.
Which tests can be affected
Tests that regulators and labs have flagged include some thyroid tests (TSH, T3, T4), troponin (used when a heart attack is suspected), and some reproductive hormone and vitamin D assays. Not every lab uses biotin-sensitive methods, which is why the lab is the best source of advice.
What to do before a blood test
- Tell your doctor and the collection centre that you take biotin, and at what dose.
- Ask whether you should pause it and for how long. Labs often suggest pausing high-dose biotin for a few days, but the right interval depends on the test and your dose.
- Never stop a medicine or change a prescribed treatment based on a supplement without advice.
Biotin in Glow Maxx
Glow Maxx and Glow Maxx (No Added Iodine) each contain 5000 mcg of biotin per capsule, and both labels carry a biotin blood-test warning.
The TGA has advised that biotin can interfere with some laboratory tests and recommends telling your health professional if you take it.
The FDA has issued a safety communication that biotin can interfere with certain lab tests, including troponin, and asks people to tell their doctor about biotin use.
Questions, answered
How long before a blood test should I stop biotin?
Does 5000 mcg of biotin affect tests?
Is my result wrong if I took biotin?
* 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. Information on this page is general and isn't medical advice. Talk to your doctor or pharmacist about your own situation.