# Biotin affecting thyroid test results



## Janey (Aug 12, 2017)

I recently learned that taking biotin supplements can affect thyroid test results causing both false positives and false negatives for both hypo and hyper. It's not because biotin affects the thyroid but because biotin is used in the processing of the lab samples and therefore having it in your system affects the processing.

The reason I'm asking is because my TSH was steadily rising and my FT4 was steadily declining. Because of my very low salt intake (thus low iodine intake) and symptoms my feeling is that I was headed towards hypo-t if not already there (but they weren't high enough for my doctor to think so). However my latest results from October show everything perfectly normal, so normal that even the most hypothyroid loving doctor wouldn't be able to find a thing wrong with them. I started biotin supplements a month or two before the latest testing (hoping to stop my shedding hair) so now I am wondering if that could have affected things giving me a false negative.

From reading it appears that large doses definitely affect results but I'm not able to find much about smaller doses (I'm taking 1000 mcgs a day). Does anyone know anything about this?

Thanks, Janey


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## creepingdeath (Apr 6, 2014)

If you live in the United States I doubt you have iodine deficiency.

I love salt and load it on everything and always did....but still got hypothyroidism.
If lack of iodine causes hypothyroidism, how come it won't fix it?


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## Janey (Aug 12, 2017)

Hi and thank you for responding. I think you may have misunderstood my question. I was asking if anyone knew about biotin affecting thyroid testing. Studies have shown that high levels of biotin supplements (10,000 mcgs) definitely affect testing causing both false negatives and positives for both hypo and hyper. Most people get and need about 30 mcgs a day. My supplement is 1,000 mcgs. I have not been able to find anything showing that this amount can or can't affect the thyroid testing and was wondering if anyone knew. My tests were seemingly heading towards hypo until my latest tests which were perfectly normal (and I had been taking biotin prior to the the latest testing).

I only mentioned about the iodine deficiency as that is what I believe may be causing me to have problems. Iodine deficiency certainly can occur in the US if one does not eat iodized salt or dairy products or seafood. Those are the three main sources of iodine in this country and my diet includes almost none of these. If my problem is an iodine deficiency, then yes, including more iodine in my diet probably will help, but again, that's not what I was asking. Iodine deficiency is just one cause of hypothyroidism. I wasn't implying that eating enough iodine will prevent thyroid problems.

Thanks, Janey


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## Lovlkn (Dec 20, 2009)

The only way to know for sure is to give up the biotin you are taking and retest in a few months.

Have you been testing antibody levels along the way? Antibody levels can impact lab results.


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## creepingdeath (Apr 6, 2014)

I did not misunderstand your question.
You have to be extremely deficient in iodine for many years to become hypothyroid from it.
And replacing it with proper eating with iodine enriched foods should rectify the problem.
Overt or autoimmune thyroid disease is not caused by iodine deficiency.
And iodine or biotin will not fix it.
Only the proper kind and amount of thyroid replacement therapy for your unique you will make you feel better.

Try eating food with iodine and see if you feel better.
Many more foods than you mentioned contain iodine.

If taking iodine does not work I would look for another reason for your symptoms.

GOOD LUCK


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## Janey (Aug 12, 2017)

Sorry for the confusion. My question is *not *about iodine (I only mentioned iodine in passing as that is why I think I have thyroid problems and in retrospect wish I didn't mention it at all).

My question is solely about biotin and how much supplements can affect the testing. Large amounts of biotin supplements do not affect the actual thyroid levels in the body but do affect the testing/results because biotin is used in procedures to test the blood. I was asking if anyone knows if smaller amounts of biotin supplements likewise can skew the results.

https://endocrinenews.endocrine.org/january-2016-thyroid-month-beware-of-biotin/


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## creepingdeath (Apr 6, 2014)

I'm sure almost everything you take or eat effects your thyroid along with having other health problems too. Getting pregnant or even the common cold will effect TSH......
I do understand your question.
You have symptoms and you think they are thyroid related but lab work and your doctor state otherwise.
So you are trying anything to feel better.

I was given synthetic T4 only med's when diagnosed.
This hormone made all my labs within the ranges and shrunk my extremely large goiter but caused my symptoms to increase 10 fold along with causing even more symptoms.
So I am stating to you that lab work and symptoms don't always correlate with each other.
But without any hormone TSH went into the hundreds but symptoms stayed the same.
So you can see how difficult it is to diagnose a thyroid problem.

Also doctors are very leery of people "women in general" looking for a quick way to lose weight.

If you truly believe you have thyroid issues you need to eliminate all other potential causes for your symptoms.
Then you need to be persistent and find a new doctor....

The good thing is if you truly do have thyroid issues your symptoms will only get worse as time goes by and you will start getting definite signs like a large goiter on both sides of your neck.

GOOD LUCK TO YOU......................................


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