Thyroid UK
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Sea kelp and levothyroxine

I'm just wondering if anyone knows whether it would be worthwhile taking sea kelp supplements as well as my thyroxine (150mg). I don't feel like the thyroxine is fully managing my symptoms, but my doctor won't increase the thyroxine as my bloods are within range, and I'm just wanting to see if there is anything I can do which might help. I take selenium, vitamin b complex and fish oils as well.

Any advice would be gratefully received..

8 Replies

Hi sally1246

It isn't advisable to add kelp (or iodine supplements) when taking levothyroxine.

If you can get a print-out of your blood test results, with the ranges and post them (on a new question if you don't have them to hand) members will respond.

Your doctor is wrong if he is keeping your TSH 'in range'. We feel best if our TSH is around 1 or below and some of us need a suppressed TSH. Don't let the doctor ruin your health. The object of thyroid hormone replacements is to erradicate symptoms and make us feel good. Tick off your symptoms on this link below:-

This link may be helpful too and ask your GP for a Free T3 test and if he (or the lab) wont do it, maybe get a private one and info is on


Hi, you'd be better off with an iodine supplement that contains the same ratio of iodine and iodide as Lugol's solution. There are several available to buy online.

Regards, Katy


Katy you should be aware that in most cases taking iodine is not advisable especially alongside Levo.


Sorry but that's mistaken - based on research that did not take account of selenium levels. I've been taking the correct form of iodine for over a year now with wonderful results. Iodine should always be taken alongside selenium and there are many of us taking both with our thyroid medication and doing very well.

You need to look beyond the headlines because iodine has been given a bad press - you can't patent iodine and when the drug companies tried to combine it with other ingredients to produce money-making medicines, they blamed the iodine for their failures. See the work of the late Guy Abraham.

There's a lady on the Stop the Thyroid Madness site who is writing a blog about her iodine journey.

Regards, Katy

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Avoid products such as kelp, as they may interfere with thyroid function & wellbeing. Kelp is derived from seaweed and is naturally high in iodine. Because of this it is sometimes marketed as a "thyroid booster" and can be purchased in dry preparations and tablets. As with iodine itself, it is of no health benefit to those with thyroid disease.


People with hypothyroidism should avoid preparations high in iodine as it can make the condition paradoxically worse. Additionally, in certain people it could provoke hyperthyroidism.

The British Thyroid Association has issued the following statement on the use of iodine supplements and we have advised our members accordingly

o The thyroid gland requires iodine for normal function. Adults need 150mcg of iodine per day.

o Typically we obtain the iodine we need from a normal healthy, balanced diet. Table & cooking salt in the UK contains little or no iodine. Too little iodine can result in thyroid swelling (a goitre). Goitre in the UK is not due to iodine deficiency Too much iodine can be dangerous and cause either under activity of the thyroid (hypothyroidism) or, in some cases over activity (hyperthyroidism).

o If you are taking thyroid hormone (eg. levothyroxine) for hypothyroidism or for a goitre (an enlarged thyroid gland) there is no need to supplement with iodine. It will do no good.

o Also, it can be harmful and dangerous to take iodine if you have an overactive thyroid, even if you are on standard anti thyroid drugs, as the extra iodine counteracts their effects.

o Should you take iodine supplements at any time? Only if it is recommended by your GP or hospital consultant."

We will agree to disagree :)


STTM 2 had an article suggesting iodine was good if hyper but not for hypo.


Hi Treepie, Iodine works for both. Until I reached sufficiency it was wonderful for my hypo symptoms. Then I was taking too much because the iodine started working to dampen down my thyroid levels. I reduced my dose drastically and I'm now fine on a low maintenance dose. If you look into the research and even 'how to' sites such as you'll find info on iodine working for both hyper and hypo.

Regards, Katy


Thanks Katy for the interesting website which I will explore when I have time.

As for iodine or anything else for that matter ,we are all different metabolically the general view is that it is damaging but if it works for you that's OK. I get a little in a multi vitamin which the producer said was not a problem because excess is excreted .But then he would say that.


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