Thyroid UK
87,812 members102,501 posts

Are vits B6 & B3 best avoided?

I had been using these vits for help pmt and mood etc but recently found out that both have a 'negative effect on thyroid function.the B6apparently decreasesTSH and B3decreases thyroid binding protein(which is only a potential problem if u r not on T4med)and results in a decrease of total(but not free)thyroxine.I am not on T4 med so maybe its best avoid high doses of B3?(what doesthyroid binding protein do exactly;i cant remember ?)

2 Replies

The binding proteins hold onto the thyroid hormone so that it can be safely transported around your bloodstream. (When thyroid hormone is bound to a protein, it is inactive.)

The thyroid hormone+binding protein acts as a reservoir for thyroid hormone.

That is, we see Free T4 numbers all the time. If Free T4 dips, then it can be made up very quickly by unbinding a little bit of the T4 that is whooshing around but bound.

Changes to amounts of binding protein can have some impact. If the amount goes up, then that can cause a short-term drop in Free T4. If the amount of binding protein goes down, that can cause a short-term rise in Free T4.

Lots of things affect binding protein levels. That is why the Total T4 is very largely unimportant - because it reflects the amount of binding protein.

In addition to Thyroid Binding Globulin (the main binding protein) we also have Albumen and Transthyretin which also act similarly.


1 like

Thanks for reply;u r brainy!so it doesnt sound like i should worry too much about adverse effects of supplementingB3,guess.not sure about what way b6 reduces tsh,but doesnt sound good.Merry Xmas!


You may also like...