Levo and iodine. Any experience of this combo?

Hi all. Anyone taking iodine with levo and what experience did you have? I'm struggling .... 50mcg almus levo gives me horrid side effects but 25 mcg mercury pharma I'm OK with (no side effects) but retain hypo symptoms. I tried alternating days of 25 and 50 but again side effects. My gp is lovely but says she's out of ideas and never had experience of someone reacting like me. Suggested I mess around myself with the 25mcg mercury pharma - alternating one and one and a half tablets. I saw a private gp a few weeks ago who suggested I take iodine to increase absorption so also thinking of doing that but I'm a bit scared it may make me Ill also. As noone seems to yet know why I can't take 50 without side effects I'm worried increasing absorption of 25 might have a similar effect so I'm really interested to hear anyone's experience of taking iodine especially anyone whose had side effects the on a higher dose.

My side effects initially were pricklyheat sensation, burning up, burning eyeballs, itchy, weak top left arm, stiff neck\shoulders. These side effects reduced generally although I kept the weakness in my left arm, got a feeling of burning in a ralgex sense on my right breast, loss of appetite and dry mouth. I also started to feel breathless and very unwell in myself. I dropped to 25 and all these effects seemed to go within 2 weeks. Gp then suggested alternating 25 and 50 which I did and within 24 hours started getting an ache in the side of my lower back which developed in a week to a feeling that I had a knife sticking in me (got worse in the evening and seemed to peak in pain terms around 3 am), ralgex breast returned, protruding sensation of eyes (which were also puffy), feeling very unwell in myself again, itching where the knife was and the front of my belly opposite where I felt the knife. Stopped the 50 and again the side effects the started to go or lessen within 24 hours.

The iodine route is just one thing I'm considering. About to do a separate post about splitting the dosage but do let me know other thoughts.

PS gp didn't really seem interested in discussing whether fillers were to blame but as most of the symptoms seem to be hyper like Im betting on the issue being struggling with the dose especially as I know I'm always sensitive to medicines.

Thanks for any help folks. Xx

26 Replies

Will your pharmacist not change your Almus levo for Mercury Pharma if you found that better.

Sometimes, it is the fillers/binders in some products which affect us badly.

I'd ask for Mercury Pharma only for a period to see if that's helpful. Also, another thing I've read that if you take one anti-histamine before 1 hour before your dose of levo and don't have any side-effects, it is the product which is affecting you and you should ask for a different make.

Yes I have a 3 month supply now of the 25 mcg mercury pharma which I'm going to play around with. Just trying to compose a list of ways to play, hopefully in a way that doesn't make me Ill again.

Steering clear of almus just in case it is the fillers


I didn't get all the symptoms you did, but I did have a rash and was very itchy around the throat, chest area when I was given a different make of Levo to my usual Activis once.

After reading the ingredients of both, Acacia powder filler seemed to me to be what I could have been allergic to.

Going back to Activis, it all cleared up. Now the pharmacist has it on record that I can only be given that one and she orders it especially.

Do you also take selenium?

No. Bloods showed I had ferritin levels on the floor and borderline vit d so I've been taking supplements for about a month. B12 was slightly high as was potassium but gp wasn't worried about b12 and said she'd routinely monitor potassium but she wasn't concerned about that either. Don't know that selenium has ever been tested though.

How much iodine are you taking? Are you deficient?

From everything I've read on the subject, Iodine should only be supplemented where there is a known deficiency. It is essential that selenium level is good before supplementing iodine, apparently 200mcg selenium per day is recommended, starting a month before taking any iodine, as iodine given where there is poor selenium status can worsen Hashimoto's.


Hmmm I'm glad I asked first (not for the first time I am very grateful to the folks on this site sharing their knowledge!). I'm not hashis. He suggested the iodine purely to increase absorption of levo based I think on my moaning of side effects. There was never any discussion about selenium...... nor was there any test for iodine deficiency. I think Im going to cross it off my list of options. Thanks Josie'smum. X

Selenium is essential in any case, I've read that 2-3 Brazil nuts a day is a good amount. If you are seeing a private doc, you could always ask them to test for iodine deficiency.

Only the nuts vary in selenium dependent upon where grown!

Yes, and how big they are and how much you crunch them up!

Why on earth would he think that iodine would increase the absorption of levo? I can't see the connection. That's not what iodine does.

Iodine is necessary in the production of thyroid hormone. One molecule of T4 contains 4 atoms of iodine. Therefore, if you are taking T4, you are already taking iodine. Has it helped your absoption? I Don't think so. However, the iodine that is released, when T4 is converted to T3, is recycled. So, adding more iodine to that could easily make you over-dosed on iodine. Which is not a good idea.

Have you had your cortisol levels measured? Low sodium and high potassium are indicators of adrenal insufficiency. If you don't have enough cortisol, you cannot tolerate a full dose of thyroid hormone.

Thanks. No I never had that tested.

Actully sorry I did. Sorry. Ages ago. It was 312 nmol\l. Ref range was 171-536 nmol\l. The lab results said 'this is a non diagnostic value. A short synacthen test would be needed to exclude hpa axis insufficiency' but I never had that test. Thoughts?

If it was ages ago (years?), then it needs to be redone. Physical signs would be tanning under your arms or other areas, hypoglycemia or low blood sugar, low blood pressure.

It was about 3 months ago (sorry that's ages to me as I feel like a pincushion from all the blood I've given and like a yo-yo to the docs). Blood pressure is normal, no tanning and I just got tested for diabetes so assuming glucose levels were ok (forgot to ask for copy of last results where I think they tested for more of less everything and it was only the potassium that was flagged as being a bit high). Thanks for the further info xx

Sorry not sure if you saw my reply as managed to do it to myself 😅. I did have the test.

Have you tried taking anti histamine along with the thyroid meds?


No but Shaw's suggested that also

I was veering toward it being the dose as most of the symptoms do seem sort of hyper symptoms but I will try the histamine and see if any help. Thanks. X

Do you have your thyroid blood results you can post? Just wondered out of interest.

Sure. The last test had done was when I'd had 7 weeks of levo hell on 50 mcg day. The results were as follows (test range in brackets)

Tsh 2.8 (.270-4.20)

T4 12.56 (12-22)

T3 3.6 (3.1-6.8)

Tpo negative

Also of note I hadn't taken the levo the morning of the test.


You are on a very low dose of T4 .

There is much dispute about iodine when hypothyroid.Some docs say should not take at all as a supplement ,a few say ok if with sufficient selenium.

Not clear when you were diagnosed but it took over a year before i started to feel just about OK and i still have some symptoms: cold feet and struggle up hills but age is a factor.

Bloods showed I had ferritin levels on the floor and borderline vit d so I've been taking supplements for about a month.

I think these two things are probably a big factor in your intolerance of thyroid meds. When I was low in iron thyroid meds made me feel hyperthyroid with fast heart rate, fluctuating BP, palpitations, anxiety...

Low or high cortisol will make tolerance a problem as well.

If your problems are very severe then you may need to stick to a low dose for a long time while you investigate and treat any low vitamins and minerals, and also investigate the possibility of low or high cortisol.

Interesting. I'd kept saying that I was concerned I would have low iron levels as I dont eat meat but noone thought it was relevant enough to discuss further . When my private blood test confirmed the low ferritin level (8.8 and test range 13-150) i took strong iron tablets. The last NHS test I had said haemoglobin was ok but they didn't check ferritin. When I asked my gp if she thought the low ferritin was a factor in the side effects she didn't look convinced and referenced the later haemoglobin test as being normal. She didn't have any other explanation to offer as to why I was struggling

You say you are supplementing vitamin D - is this just vitamin D on own, or does it have magnesium and K2 included.

When supplementing just vitamin D it can exacerbate possible low magnesium.

You need good level of magnesium for thyroxine to work too

Magnesium was in range (just) 0.74 (0.70-1.00) and it's just strong vit d tablets. 25 mg.

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