T4 conversion problem: A specialist has... - Thyroid UK

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T4 conversion problem

A specialist has recommended to take the following to try to help with conversion after blood tests showed as deficiency in magnesium and selenium.

i) Women’s multi essentials multivitamin – take one daily ii) T-convert, take 2 capsules daily

iii) 25-Vitamin D3, 5000 units once daily

iv) Magnesium glycinate one tablet three times a day and at bed time.

v) Similase one tablet immediately before all meals.

vi) Gall plus one tablet immediately before a meal.

vii) L-carnitine 500mg before each meal

A probiotic Proflora 50B

With all the other medication that she takes, this is just far too much from my mum to remember and do everyday! She is stressed about it - it is also so expensive.

Can anyone recommend a combined vitamin that would support her with these things that is just one tablet. Thank you.

12 Replies

Did you get her vitamin D, folate, ferritin and B12 tested?

Add results and ranges if you have them

Vitamin D, she could use vitamin D mouth spray at 3000iu strength

Getting a daily pill dispenser with multiple sections, fill it up once a week

Her magnesium level is likely low due to being on PPI (Lansoprazole or equivalent)

Only ever add one supplement at a time and wait at least ten days to assess results before adding another

Vitamin D is likely most important. Followed by magnesium. Usually people only take magnesium once daily

Vitamin D mouth spray can be used about an hour away from taking Levothyroxine

But magnesium and vitamin D capsules both need to be four hours away from taking Levothyroxine

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Thanks for your reply. She had full bloods done privately. Antibodies and all other bloods ok except magnesium & selenium.

High reverse T3. T4 & TSH.

He suggested a conversion problem & problem in her gut.

However they found a parasite and have prescribed an antibiotic for this hence the probiotic.

I was hoping to find a supplement that included selenium & magnesium in one tablet to make it less complicated to take with all her other meds.

I've emailed the consultant back asking for something simpler & less expensive. Was just wondering if anyone on here has experienced the same & could recommended a supplement for these two minerals.

Thank you.


I doubt you would find these two supplements in combined pill

Search on Amazon perhaps

Most people take selenium and magnesium separately.

You mum is legally entitled to printed copies of actual results on vitamin D, folate, ferritin and B12, TSH, FT3 and FT4

Low B12 is very common as we age and when hypothyroid


As suggested by SlowDragon a weekly pillbox -they come in various sizes - is ideal especially if the person may easily get confused if taking individually from containers.

I've got one myself and my husband also. It is very convenient. As husband takes more tablets than myself his daily container takes more tablets than mine.

It is especially useful if on some days there coud be an additional pill needed.

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What sort of "specialist" recommended all those supplements? Are they a qualified Dr? Are they wanting to sell all these supplements to her? Looking at the info about T Support, apparently it contains mukul myrrh extract (gum guggul), selenium, zinc, copper and magnesium; so she is getting selenium and magnesium in one tablet with that - but whether at the correct level is another thing, and whether she needs to be taking copper is another question, as is why is she also being recommended magnesium separately. You don't mention which multivitamin, so I don't know what is included in that, but it may be/likely is doubling up on some of what is in T Support, but in any case, multi-vits are advised against for a number of reasons. The Gall Plus includes all manner of things including bovine liver and pancreas and also B1, B2, B3, the latter which again, might also be included in the multi Vitamin.

When you write "High ReverseT3, T4 & TSH" do you mean each were high, but in any case what are the actual results and their reference ranges? Presuming T4 was actually FT4, unless the FT3 was also tested and found to be low, how did the specialist conclude there was a conversion problem? I'd suggest you post all the results in order that folks can comment directly on them, and identify what might be going on and/or which of all those things, might or might not be needed.


Thanks for your reply. The Dr is an endocrinologist recommended by her insurance company. He seems very interested in mum and keen to help.

We left the appointment thinking she needed an antibiotic & probiotic which I totally understand together with a Selenium & Magnesium supplement.

Mum takes thyroxine, warfarin, statins, sotalol and an antacid for Barrats oesophagus. Taking all the supplements that he suggested ( mentioned previously), several times a day on top of her other meds that just stressed mum out! very expensive and so many!

I don't understand the information in the letter but this is the bloods result info we were given to pass on to the GP in a letter asking for antibiotics to cure her of the parasite that was found in the stool test.

Thyroid replacement. Her TSH was 5.33 miu/L, fT4 21.9 pmol/L, fT3 3.7 pmol/L, reverse T3 37 ng/dl (10-24), TG and TPO antibodies were negative and whole blood selenium was 92.3 mcg/L (85-200). Thus, the high fT4 to fT3 ratio suggests together with the high reverse T3 that she has difficulty converting T4 to T3. Her selenium is low – normal and I therefore wondered in the first instance if this might be an important cause. I have recommended selenium supplementation to achieve a level no higher than 200 mcg/L as there is a Goldilocks phenomenon effect with selenium.

I have also recommended she increase the dose of Levo-Thyroxine to 75mcg once daily and recommended treatments to address the other abnormal findings – see below – which hopefully might have a beneficial effect for example, on absorbing Thyroxine. If, however, she is still symptomatic and has a high fT4 to fT3 ratio despite improvements elsewhere then we might need to consider the possibility that she genuinely cannot convert T4 to T3 and tackle the problem accordingly.

Micronutrient deficiencies. Red cell magnesium was reduced – 1.18 mmol/L (1.19-1.73), CK 71, Vitamin D 36 nmol/L. I have therefore recommended supplementation accordingly.

4. Lipid profile. TG was 0.8, TC 4.6, HDL 2.0, non-HDL 2.6.

I have contacted him asking if he can condense the supplements needed for her to make it easier and am waiting on a reply. I just wondered if any other people took both of these supplements to help conversion problems.

We are to repeat bloods and stool test in 8 weeks to see if she is converting better and if parasite has gone.

Do you think the parasite would stop the conversion? Mum was on 75mg for 30 years with no problems, a statin was introduced and sometime after which is probably coincidental, her levels starting going high and the GP was unable to control them that's why we got referred to endocrinologist.


I have the feeling that your mum's endo just wants to appear to be doing something, without really having thought the whole thing through! Totally impractical!

* Multi-vitamins are rarely a good idea, for anyone, but especially not for hypos. I don't know the contents of this particular one, but they usually contain cheap ingredients and things we shouldn't be taking, like calcium, iodine, copper. And, if they also contain iron, then you will absorb very little if anything, of anything! That's why we never recommend multis on here.

* Then, the T-convert contains more of the same: copper, zinc, selenium. She'll likely to over-dose on some of these things. And, I bet he hasn't tested her copper and selenium first. Hypos are often high in copper, so it should always be tested before taking any. Excess copper is a very unpleasant thing!

* Why the Similase? Does she have digestive problems? If so, there's better than this. This contains soy lecithin, and that's not good for hypos.

* Magnesium glycinate three times a day? There's already magnesium glycinate in the T-convert. So, how much does that add up to a day? What type of magnesium is in the multi? It all adds up. Plus, you need to leave a four hour gap between magnesium and thyroid hormone. So, how is she supposed to fit that in?

* Gall Plus? What's that supposed to do? It contains yet more soy lecithin.

I think this whole plan needs scrapping and rethinking. It's messy and unscientific. And, not certain to improve conversion at all. Depends on the problem: why isn't she converting? And, certainly more testing should be done before taking things like copper. I'd call that 'over-doctoring', myself.


More generally, I agree with GreyGoose re multivits. I have been on one for a whole year and my latest labs showed several deficiencies/suboptimal levels. So a waste of money IMHO.


Seen the results you've given above, and the TSH is much, much too high. So, she is under-medicated. But, can't comment on the FT4/3 because you haven't given a range.

The rT3 is probably high because her FT4 is high, but there are many reasons for high rT3, not all of them to do with thyroid. It shouldn't be her main preoccupation, anyway.

She should not be taking a statin. And that might have something to do with her problems. Her cholesterol is high because her FT3 is low. But, do have a look at this article out-lining all the reasons why she shouldn't be taking a statin:


I cannot understand why he is giving an antibiotic for the parasite. I didn't think that was the usual treatment. But, I doubt if it has anything to do with her conversion problem. Some people just cannot convert well.


Thousands of patients on here - the main vitamins that should be tested are Vitamin D, folate, ferritin and B12

Clearly her vitamin D needs improving. At 36nmol it's well below NHS minimum and she could (if she wanted) insist that GP prescribes 2 x 800iu vitamin D per day for 6 months free on the NHS.

Any vitamin D that is swallowed must be FOUR hours away from taking any Levothyroxine

Vitamin D mouth spray, can take about an hour away from Levothyroxine. NHS won't prescribe mouth spray (too expensive)

Local CCG guidelines clearly show what GP should prescribe to improve vitamin D


A GP will not prescribe any magnesium. There are many different options on magnesium. ALL magnesium needs to be four hours away from taking Levothyroxine

If your Mum tends to suffer from constipation, then Calm vitality magnesium powder is cheap and easy to use. Very good at improving constipation, but can cause opposite problem of diarrhoea if take too much

Ferritin, B12 and folate all need testing. Ask GP to do so

Or add results and ranges if you have them

Selenium, lots of different options. Combined with vitamin E may improve uptake and yeast free



Multivitamins are not usually recommended on here, as outlined so well by greygoose

Your mother may no longer need statins at all

High cholesterol is symptom of being under treated for hypothyroidism.

NHS clearly says that anyone with hypothyroidism should not be prescribed statins while Thyroid is NOT correctly treated.


If you have an underactive thyroid (hypothyroidism), treatment may be delayed until this problem is treated. This is because having an underactive thyroid can lead to an increased cholesterol level, and treating hypothyroidism may cause your cholesterol level to decrease, without the need for statins. Statins are also more likely to cause muscle damage in people with an underactive thyroid.

When on Levothyroxine TSH should be under 2 (many need TSH well under one)

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l.

Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor

 please email Dionne at



Hi SlowDragon, I have never before read of an interaction with swallowed Vitamin D and levothyroxine requiring a 4 hour separation of the two. Can you please pass on where you came across that info?

Also, I’m sorry to be the harbinger of bad news - meant to share this earlier as I’ve seen NC recommended previously as well - but Labdoor found Natural Calm to have relatively high levels of inorganic arsenic in their magnesium supplements review.

labdoor.com/rankings/magnes... This may not be of concern to all as the level was high relative to stricter proposed rather than current limits in California, and Labdoor uses a calculation rather than (apparently expensive) direct testing to determine inorganic vs organic arsenic. But especially for hypos, seems prudent to avoid heavy metals as much as possible. I don’t agree with exactly the way Labdoor ranks supplements overall but do think their testing is useful.


Whatever the list is whittled down to only introduce then one at a time and leave 2-3 weeks in between. That way if anything upsets the system then its far easier to work out which on it is.


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