I would appreciate your thoughts regarding biotin supplementation and how much time one should leave between a dose of biotin and a blood test measuring FT3, FT4 & TSH? I am really not sure, and getting conflicting info online. Some say 24h is okay, and other sources say anywhere between 3-7 days.
The last dose of biotin I took, was 150μg in my multivitamin. That was last night, which at this moment in time was around 24 hours ago. The blood test is due tomorrow morning, so when my blood is taken it will of been around 31-32 hours since I took the biotin. Would this be okay?
Thank YOU!
Written by
elliscp01
To view profiles and participate in discussions please or .
Morning, read somewhere to not take biotin at least 7days before thyroid blood tests, it can interfer with your results. This is what is says on my test results from lab.
*This assay may be affected in patients taking Biotin supplements.
It’s depends on if the testing process involved is using biotin-streptavidin reagent & your blood contains high enough levels of biotin.
A supplement containing 50ug likely won’t affect test, 150ug - which is typical level in for example a hair & nail supplements - might need 24 hours.
A max dose or high dose might need 3-5 days.
A multiple sclerosis patient who might be trialled or prescribed 600 mg would need to cease a week (or use a lab where biotin won’t interfere with test).
Being aware of the possibility biotin could affect test and leaving off dose before hand is a precaution, most cases a few days is all that’s required.
There is no official x dose of biotin = x days / hours of withdrawal. It’s guesswork, which is why there is a huge vary is suggested time.
Have you always taken this supplement and if yes did you stop it prior to any other thyroid test if so how long before previous blood test did you stop?
I have just had my blood test results back and biotin seems to have interfered with them. The problem is that I am not aware that I have ever taken any biotin. What is it in? I have checked my B12 and iron tablets and it doesnt seem to be in them. I don't think it is in Grossman's Cynomel or nutrigest either. As far as I am aware those are the only things I take. Any ideas anyone?
The issue with biotin was identified when some people with Multiple Sclerosis were trialling gigantic biotin doses to see if it helped. Some of their blood tests came out odd and the issue was shown to be biotin.
Ordinary dietary levels of biotin (that is, what is found in food) has no effect.
Most vitamin tablets which contain some biotin (also known as vitamin B7) have little more than would be expected in a good diet. But a few, especially the higher dose B-complex or single-ingredient biotin products, do have enough to affect tests.
I don't really understand why you think there was biotin interference if you don't take any obviously significant sources of biotin?
You'd be better writing a brand new post than adding to another thread.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Possible silly question about biotin
Advice on Blood Work Please 
T3 adjustment and blood work 
Need help with blood work
Stop t3 for blood work?
