How Biotin Impacts your Thyroid Hormone by Suzy... - Thyroid UK

Thyroid UK
101,261 members115,570 posts

How Biotin Impacts your Thyroid Hormone by Suzy Cohen Pharmacist

There was a medical conference held in San Diego California recently and a physician presented a case study about a woman who took a large amount of B vitamin called biotin. I’m sure you’ve heard of it, it’s the B vitamin that everyone takes to try to get thick hair and strong nails. Anyway, the 55 year old woman’s level of thyroid hormone spiked so high she experienced thyrotoxicosis (extremely high levels of thyroid hormone), yet she had no history of Graves’ disease, Hashimoto’s thyroiditis or thyroid disease of any sort.

The problem arose from the woman taking a high dose of biotin which she was using for multiple sclerosis (MS). They could not fully explain why the spike in thyroid levels had occurred, they think it might have something to do with assay interference, but regardless this case study poses an excellent warning to practitioners about the phenomenon. It’s not the first time biotin has come into the spotlight, there was a December 2012 article published in the scientific journal, Pathology which suggested a connection.

8 Replies

Whilst it is quite true that biotin. particularly some of the high or very high doses that have been used in recent years, can and do make tests come back indicating hyperthyroidism, the lack of understanding as to why is somewhat strange.

There are many papers. And it has been mentioned here (and over on pernicious anaemia society forum) for some time.

It is also a surprise that she suggests stopping 3 to 5 days before a blood draw. There might have been further research published, but last I read, time from high or very high dose had not been established.

False biochemical diagnosis of hyperthyroidism in streptavidin-biotin-based immunoassays: the problem of biotin intake and related interferences

The important thing is, of course, to keep awareness of this high. Make sure it cannot be brushed under the carpet and forgotten. :-)


Biotin by itself does not affect thyroid hormone levels in blood. What happens is that some, and by no means all, tests for FT4 and FT3 use a reaction between a protein called streptavidin and biotin to get a value for the hormone levels. Adding biotin interferes and will give spurious answers. Relatively few but commercially often usedt tests use this method and those that don't should give the right answer.


Thyroxin didn't help me at all. My T4 levels weren't all that bad and since the Thyroxin only gives T4 replacement it was of no use to me. I was very low on T3 which thyroxin did not replace. So I was no better taking it and felt very ill. I ended up taking natural pig hormone. Bovine hormone i.e. cow did not agree with me either. The pig is the best for me and it works...creating a balance in my body like no other medication. Thyroxin is synthetic T4 and if this is what you are low in then fine use it but if its T3 your lacking then leave it well alone since it will make no difference at all. Hope this helps.


Hi Mallard2059, Susie Cohen’s article is on Biotin formerly known as Vitamin H.

I’m pleased that you’ve also found the correct solution for your thyroid medication in the form of porcine T3. I’ve found a sweet spot with a T4/T3 combination. Addressing the underlying stealth infections to lessen the toxic burden and boost my immune system is my current work in progress.

Best Wishes


Hi mourneadventurer and others with graves, do you have a known infection either candida or EBV as examples, reason I mention this is mostly with autoimmune issues theres a critter involved, get rid of the critter and the thyroid will most likely correct itself as the reason for the problem is not there anymore


Thanks roadrunnergreg. I had done standard 3 day stool tests and vital key components were not picked up over 3 separate tests 6 months apart. Back in December I did a GI Map Test by Invivo which looks at the genetics and bingo I’ve got the root cause and they’ve been taking my immune system down. Now to reverse it keeping T3 and T4 in the zone.

Best Wishes


The Suzy Cohen article has been discussed here fairly recently :


Thanks Humanbean, I’m glad the article has provided a basis for discussion after I initially posted it 15 days ago. Makes the effort worthwhile!


You may also like...