I have been wondering about Vit B and my thyroid tests. It seems that opinions vary on how long before a thyroid blood test you should stop B vits with Biotin, it seems to vary from 2-7 days. I read somewhere the Biotin can lower or raise FT3. If thats the case then stopping B vits at 2 days or 5 days or 7 days prior might/should presumably give different lab results? ie different at each of those ie 2 days/5days/7 days.
Perhaps more importantly if B Vits or Biotin affect the thyroid lab results (we seem to advocate on here that B vits are important) then are the labs going to be accurate if Biotin /B vits are stopt 5-7 days before because normally we take B vits every day so presumably the theoretical FT3 reading will be different if we take B vits on a normal day. I hope I expressed my puzzle accurately enough.
Has anyone put this to the test, ie take B vits even the morning of the test as normal or maybe 24 hrs before and do a blood test for FT3etc and then stop the B vits/Biotin and test again in say 7 days to compare?
Written by
ainslie
To view profiles and participate in discussions please or .
Has anyone put this to the test, ie take B vits even the morning of the test as normal or maybe 24 hrs before and do a blood test for FT3etc and then stop the B vits/Biotin and test again in say 7 days to compare?
I don't think that would give you any coherent answers because biotin may or may not give a false high FT3 - or it may or may not give a false low FT3 - or a false high/low TSH/FT4 or any other test you care to mention. It's effect is totally unpredictable but is only a problem with test that use biotin in the testing process. I don't think it's an experiment that any one individual could do with any success. It would have to be done in a laboratory, under controlled conditions.
Of course, it does depends how much biotin you're taking. The biotin you would find in your average B complex is said not to be enough to cause a problem.
But, then again, when you get down to it, how accurate are blood tests anyway? There's a huge margin of error.
It's more of an issue with people taking high doses of Biotin which the B complex's we suggest don't so a couple of days is fine, as for the skewed results that's due to it interfering with the test rather than the biotin in the blood making a big difference to daily levels
Not so in my case. I had an unexpected blood test when on Thornes Basic B complex which has biotin in it. My Ft3 and Ft 4 were through the roof. Made a massive difference. Hospital were not happy and sent a letter to my GP telling them I was over replaced on my thyroid meds. I complained and the test was repeated a week later having stopped the Thornes basic b complex and they came back with their usual ranges. My GP was aware of this issue as was my surgeon. Pre op weren't. My surgery went ahead as planned.
However an unpleasant nhs endo a year later quoted this high reading back at me a and we had a whole "conversation" about it.
If you Google it comes up as a known connection. It's not all the b vitamins its biotin. I've since had one Endocrinologist suggest I stop taking it for 3 weeks.
I do need a b vits supplement as I also need b12 jabs. Lately I've been exploring a less potent complex as have been gf for 2 years and am absorbing better.
So with Thorne containing 400mcg 2-5 days ought to have been enough like you say after a week everything was back to normal, if you were tested right after taking it then your levels would have been higher
They were high. The blood test was mid afternoon....un expected. If I recollect correctly my Ft 4 said 32 (range max was 21) can't remember ft3. I would definately not take any biotin for a week before a blood test. An endos recommrndation of 3 weeks isn't practical for me but interesting he thought that. Realky wanted me off biotin all together.
Of course everyone is different....
I thought Rotherhams Hospitals descriptions of the different assays and their effects of coping with biotin was really interesting.
Depends on how much biotin you are taking how long before test it’s recommended you stop taking it
If you’re taking vitamin B complex, we recommend stopping 3-5 days before and instead while not taking B complex ………a daily methyl folate instead and…..if B12 was low at previous test, also taking a daily B12
No methylfolate doesn't affect blood tests.....just biotin. Methylfomate daily to replace b complex whilst you stop it due to biotin content one week before blood test. (Or if u want to follow what an endo said to me 3 weeks stopping biotin!)
Biotin is in the b complex so needs the b complex needs to be stopped for one week because Biotin does affect blood test results. In the b complex is methylfolate. MethylFolate can drop quickly once supplementation is stopped via the b complex. So you take methylfolate whilst the b complex is stopped.
The same as in your own brand of b complex if you need it. If your fine without for a week thats fine. I become tired and weak but I also have high frequency b12 jabs (nhs prescribed) so likely the issue.
what is the problem if we are not getting Methylfolate for the week before the blood test (while stopping B complex) if it as you say doesnt affect blood tests, kinda confused there a bit
The methylfolate can leave the system quickly if u require methylfolate you can become depleted in your body if not taking methylfolate as part of the b complex for a week. It's nothing to do with the blood test per say.
Recommendations on here, have been to cease B Complex owing to the biotin content - and supplement instead with vit B 12 separately and Methyl folate separately. Folate will affect blood test results , as I understand it, as levels will drop and result will be lower - that would be the ‘effect’.
I saw a post on here a while back, asking if all supplements should cease before testing and I can understand the reasoning behind that - ie, do we want our results to reflect as to how we are without them, or do we want results to reflect as to how we are with them! Either would show what supplements we might need to adjust but the difference would be we might feel unwell and as an experiment, would it be worth it?
The 50 mcg D-biotin in your daily Solgar supplement is a small amount and less than the 1mg that requires stopping before using a thyroid test employing a biotin-streptavidin reaction.
High dose supplements may contain biotin amounts up to 20 mg (2000 mcg) and these require an abstinence for 3 days before the blood draw. Biotin is water soluble so leaves the body quickly.
I think that biotin has become a bit of a panic issue.
It is right that it is mentioned and discussed, but the effect on tests of the types of dose we'd get from a multivitamin or similar will almost invariably be insignificant.
Blood tests are problematic for a number of reasons, not least that we are all individuals with different optimums. I was (originally) diagnosed by Dr Peatfield, without the use of a blood test, but using morning temperature, achilles reaction, what he could see and what I could tell him and he has been proven right over the years. The TSH blood test is now considered the Holy Grail of thyroid testing, and it falls short. Thyroid disease is complex and nuanced, unfortunately.
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.
Stopping B vits before test
How accurate are Medichecks?
Vitamin B supplements
'Subclinical Hyperthyroidism' - with normal FT4 and Ft3? Don't Know What to Think...
