Thyroid UK
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Nature-Throid and Supplements Interaction

Hi Everyone,

I hope someone out there can clarify as I am a little confused! I am now finally on NDT; half a grain in the am and half in the afternoon. I know not to eat for 2 hours either side but what about supplements? I am on a long list of supplements and I am worried they will interfere with the NDT.

I know not to take magnesium, calcium and Iron 4 hours either side but what about the following;

Selenium 200 mcg

B-12 5000 mg


D3 5,000 iu

Kelp (Iodine)

Cod Liver Oil 1000 mg

Zinc 25 mg

Thank you!!

23 Replies

Forgot to mention Ashwagandha as well



Iron, calcium and vitamin D should be taken 4 hours away from thyroid meds. Other supplements should be taken two hours away. Magnesium can be a relaxant so can be taken at bedtime.

Kelp contains a lot of iodine which you shouldn't need when you are taking thyroid meds. Too much iodine isn't good for hypothyroid and Hashimoto's patients and can raise TSH and trigger Hashi flares.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


I've also read that zinc is absorbed better at bedtime.


yes, i've been told this also, thank you!


Hi Clutter,

Thank you for your reply. I was told by my Dr. to take Kelp specifically for the Iodine?


Did your doctor test your iodine before telling you to take iodine? If not, then he doesn't know what he's talking about.

There are a lot of doctors who think that all you need to do for a thyroid problem is throw iodine at it. Nothing could be further from the truth.

Excess iodine can cause all sorts of problems - including causing hypothyroidism. True, you need iodine to make thyroid hormone, but if half your factory has burnt down, shovelling in more raw goods isn't going to increase production, is it.

Besides, if you are taking thyroid hormone, you are taking iodine, because every molecule of T4 contains 4 atoms of iodine, which are removed, one by one, and recycled.

Do you know if you have Hashis? If so, taking iodine could make things worse. And won't help because your gland - factory - is slowly being destroyed, and therefore cannot make more hormone. So, taking iodine is really a bad idea.


Yes, I'm having trouble typing on this site as well. So no worries about the typos. Thanks so much for your reply, I thought that was the case, he suggesting Iodine for a small goiter. Is that still a bad idea?

Thanks again!


Well, yes, because the goitre is your thyroid, and the iodine goes straight there - and won't necessarily get rid of the goitre. What you need is an optimal dose of thyroid hormones and a complete thyroid panel :






and iodine if he wants you to keep taking it. :)


Hey Greygoose,

Thanks so much for all your help! My most recent labs are:

Free T4 (Blood Spot)* 1.2 ng/dL

Free T3 (Blood Spot) 2.8 pg/mL

TSH (Blood Spot) 1.2 μU/mL

TPOab (Blood Spot)* 92 IU/mL

DHEAS (Blood Spot) 153 μg/dL

I can't see anything about Iodine, so I'll stop taking that for now.


I'm afraid the numbers are meaningless without the ranges. :(



DHEAS (Blood Spot) 153 μg/dL 40-290

SHBG (Blood Spot) 30 nmol/L 15-120

Free T4 (Blood Spot)* 1.2 ng/dL 0.7-2.5

Free T3 (Blood Spot) 2.8 pg/mL 2.5-6.5

TSH (Blood Spot) 1.2 μU/mL 0.5-3.0

TPOab (Blood Spot)* 92 IU/mL 0-150 (70-150 borderline)


Oh, they do make me cross with their 'borderline'. Makes no sense with antibodies, because they fluctuate so much. And you don't know if that's the highest they're going to get or the lowest, or somewhere inbetween. I think the best you can say is 'don't know'.

Your TSH is okish, but your FT3 is much too low. So, you're going to need several increases before you feel any better, or before it has any effect on the goitre.

That is going to suppress your TSH, but it really doesn't matter. You don't need it anymore because you're taking T3 ready-made, as it were.

Don't bother about the FT4, either. That is going to be low when taking any form of T3 because the body doesn't need to hang on to as much. Hope your doctor knows all that! :)


Greygoose, thank you! I have only just seen this. Had a bit of a fog brain on for the last week! I was started on 32.5mg of Nature-throid twice a day for the first two weeks, but I don't feel much of a difference. :( I think it might need to up the dose!


Yes, I expect you will. But, not until you've been on it for at least two weeks. :)


:) ok Thank you!

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Greygoose, sorry for all the questions, but I cannot figure out how to 'read' my own blood tests. What do the ranges mean? Or does anyone have a link to info on this?

Thank you thank you!! x


Have a look at this thread, it might answer your questions :

1 like

Thank you!!!!




I am also taking Progesterone so I am not sure if I can take magnesium and Zink in the eve?


I take magnesium at bedtime, also progesterone. Why wouldn't you think it can be taken at night together Rhsana?


Because it made me nauseous, I now use the cream instrad

1 like

Oh dear!


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