Thyroid UK
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iodine in levo - enough?

I know iodine supplementation is controversial, but there seems to be lots of evidence linking low iodine and breast cancer. If someone wanted to supplement iodine with the aim of reducing their breast cancer risk, would the iodine in Levo will be enough? I believe it is very difficult to get an accurate test showing if you are low in iodine or not, but I'm happy to be corrected if anyone knows better.

4 Replies

Midnightblue, 65% of 100mcg Levothyroxine is iodine. That, plus iodine absorbed via diet is probably enough to meet or exceed your RDA.

Iodine is an indispensable component of the thyroid hormones, comprising 65% of T4‘s weight, and 58% of T3‘s.


Thank you clutter. I wonder then why there is an assossiation btw thyroid problems and breast cancer, if we are getting enoughiodine through the levo. It is a great worry to me.


Midnightblue, I think the association is with undiagnosed (untreated) hypothyroidism and breast cancer. If the hypothyroidism was due to lack of iodine, breast tissue will also be low in iodine.


That would be a serious relief.


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