Thyroid UK
82,694 members97,731 posts

Start T3 self medication or treat B12 vit D and Zinc deficiencies first ?

Hi, any views comments welcome. A brief history....i began to feel increasingly awful, usual stuff at first, shoulder and joint pain, fatigue, brain fog and depressed moods. Then it changed, and unusually for me I developed symptoms of IBS, acid reflux, even bile issues. Got very interested in the amazing information here and followed many links. I've been Hashimoto'd for about 10 years and been surviving (just) on a daily dose of 150 levoxythyroxine once weight had stabilized. With my recent troubles I knew I would hit the same brick wall as everyone else ... but I live in France and got hold of some cynomel. Having just tested blood I can see my T4 is over top end of range and my T3 at the very bottom of range. TSH is low at 0.2 but ideally the aim is 0.5. I am deficient in Vit D, B12 and zinc. From what I can tell ferritin and folate are in the top of the range. I am involved in an ongoing dialogue with GP, who fair enough has admitted she doesn't know enough to support me onto T4 + T3 medication so has put me on hold while she consults my ex endo. I can guess what will come back as my endo was entirely unable to acknowledge ANY negative symptoms once my TSH was below 1. So here's my dilemma, do I halve my Levo and substitute say a quarter of Cynomel to start with and see how I go...knowing I will alienate both doctor and endo, and probably find it difficult to rely on their help for blood test prescriptions thereafter, or do I treat the deficiencies first, starting with B12 and stick with the Levo hoping that a better level of vital vitamins and trace elements will start to improve my conversion from T4 to T3 ? For me the quick fix that the cynomel offers is hard to resist as I am feeling very bad particularly in the mornings. The suggestion I've seen here is that a bit of T3 can make you feel better in a matter of days. I've ordered all the supplements but they won't arrive until middle of next week and I assume a couple of weeks of high doses will be required before any improvement is felt. Does treating the deficiencies first make more sense as it leaves me with the T3 self medicating option if I still need it. Would like to know what anyone thinks especially if they have experience of dealing with poor conversion rates.

12 Replies

A quick reply to start with. A nutritional doctor told me that if you sort out your deficiencies then any medical problem will present itself more clearly.

Supplements can take time to have an effect. Best to start them one at a time, a week or so apart, so that if any disagree with you you can tell which one it is. Personally I wouldn't take high doses to start with, as you want your body to get used to your regular dose. You will also have to sort out when to take them, as some need to be taken well away from thyroid meds. Zinc is supposed to be best taken at bedtime. If you make a new post with a list of your supplements you can ask what time of day is best for taking them.

I can't see that a little cynomel will be a problem.

All the best.


Many thanks for your thoughts. I was going to start on 5000 of the B12 along with B complex as I understand they are better taken together and then reduce to a forever dose of 1000.

So I'm waiting for a delivery of the following:

Selenium 200 mg

Zinc 30 mg (with copper but not sure the dose)

Vit D3 5000 iU (not sure what iU is)

K2 100 micro grams

B12 5000 mg

Like you suggest I may take a quarter 25 cynomel just before bed having dropped my Levo from 150 to 125.

Iron is a bit difficult for me to interpret as the french blood test include Fer (iron) and I am 34.4 (range 5.83 - 34.5), transferrine 2.51 (2.00 - 3.60), but something called coefficient of saturation Fer / CTST is not good at 55% range (15 - 35). Ferritin is 76 (15 - 150).


Personally I would sort the nutrient deficiencies first. Don't start supplements all at once, add one at a time and allow about 10 days before adding another so you can assess reaction.

When supplementing B12 it's recommended to also take B complex as well to keep the B's in balance.


sort out your B12 and D - deficiencies have a huge overlap with symptoms of thyorid problems.

The acid reflux may be a reflection of low stomach acidity as symptoms of low stomach acidity are almost the same as high stomach acidity.

likely to be an absorption problem - and would be good to check that - PA is the most common absorption problem. low stomach acidity - which may or may not be the result of PA is another cause of absorption problems.. Unortunately the test for PA - IFA - is a bit unrelaiable tending to give false negatives about 50% of the time so a negative result won't rule it out as a possibility.

In France you can get B12 injections from the pharmacy - which is good news for you - but suggest you do this in conjunction with your GP ... as it would be good to keep an eye on your folate levels and also good to check for any signs of macrocytosis. Other mineral levels can also be affected when you start to treatment for B12 ... and although you can't overdose on B12 you can overdose on many other vitamins and minerals.

and suggest that you take a look at the PAS forum for advice and support re B12 deficiency

1 like

Some interesting ideas, thanks. Have posted my iron and ferritin levels above...these would suggest I'm not anaemic, is that right ? I have to figure out what they call the folate test as I can't see anything which quite matches. Also my cholesterol level is suggesting high risk of cardiovascular <1.00 mines 0.47 g/L. Also what is macrocytosis?


iron based anaemia is about iron levels. there are other forms of anaemia - such as the macrocytosis (larger and rounder red blood cells) caused by folate and B12 deficiency. Iron isn't necessarily affected by macrocytosis.

1 like

I'm assuming the Cynomel you have comes in a 25mcg pill.

Based on patient experience, T3 is roughly three times as potent as T4, so 25mcg T3 is roughly as potent as 75mcg Levo (T4).

Be aware that doctors think T3 is more powerful than patients do, and they think T3 is 4 times, 5 times, 10 times, or even 14 times as powerful as T4. (Depending on whose opinion you are reading.)

If you were to halve your Levo and only add 1/4 of a pill of T3 as you suggest, you would be very under-medicated.

I would suggest reducing dose to 125mcg Levo and adding in 1/4 of a pill of T3 taken first thing in the morning for a few days, and if there are no adverse effects then add in another 1/4 tablet to be taken later in the day.

Since 1/2 a pill of T3 is equivalent to 37.5mcg T4, then your 125mcg dose of Levo may be too high, and you might have to reduce to 112.5mcg T4.

If the only thing you want to do is to add a little bit of T3, but continue with T4 as your main thyroid hormone, then reducing your T4 a bit and taking 1/2 tablet T3 may be all you want to do.

Just remember that 150mcg T4 is roughly equivalent to 50mcg T3. So if you continued switching from T4 to T3 until you were taking T3-only then you might expect to end up on a dose of 50mcg (2 tablets) per day.

Once you add T3 to your dose of thyroid meds your TSH is likely to end up lower than it was on T4 only. Your doctor might not be happy about this. Be prepared!


This is really helpful, thanks. I had read something somewhere about taking T4 and T3 in a ratio of 20:1 and your suggestion of 125 T4 and a quarter tab of 25 T3 is exactly that. What if the TSH does go lower than 0.2, what are the implications for Hashi patients ? I'm assuming anything I do 'off piste' including the supplements is going to annoy her. My only worries were that if I take supplements to aid conversion AND take a quarter tab of T3 am I not going to find I've way too much T3 ?


Well, from the patient point of view, as long as Free T4 and Free T3 stay in range, then a low TSH should not be an issue.

1) There are no guarantees that improving nutrient levels will help conversion at all.

2) Improving nutrient levels should improve how you feel, and should be done anyway, whether you convert well or badly.

3) When TSH is very low it reduces conversion from T4 to T3. A high TSH increases conversion. So, a balance has to be struck to get the best conversion possible while still taking enough thyroid hormones to help you feel well.

From a doctor point of view, Free T4 is not very important and will only be tested if TSH is out of range, and Free T3 is completely irrelevant. The only thing that really matters to them is TSH and they don't like it to be low in range or under the range.

But you should read this link :

The full paper referred to can be found here :

You are going to have to insist that you feel well and have no over-medication symptoms if you want your doctor to keep on treating you. Just... be prepared for any kind of reaction and stand your ground.


Interesting stuff. I'm a bit disappointed that getting deficiencies sorted won't improve conversion but I guess it will improve general state of well being. The article suggested TSH 0.2 was mildly suppressed. I had been thinking it was very suppressed !

Can you clarify your last statement...what do you mean about insisting I feel well....normally I only visit her when I don't feel well or I need a renewal of my prescription. I'm going to have to eventually find a way of telling her I'm taking a bit of under the counter T3. Is that what you mean ? Once I've taken things into my own hands I'm responsible for how I feel, not her !


I'm a bit disappointed that getting deficiencies sorted won't improve conversion but I guess it will improve general state of well being.

It might improve conversion, but there are no guarantees. Until you fix your nutrients you won't know whether or not it has benefited you. But it is worth doing anyway.

You are going to have to insist that you feel well and have no over-medication symptoms if you want your doctor to keep on treating you. Just... be prepared for any kind of reaction and stand your ground.

It was badly worded wasn't it!?! Oops. Sorry!

The problem some people have is that they get their meds working well for them. Then a doctor does testing and says, you're over-medicated, drop your dose now! If the patient complies they could feel worse quite quickly, and this is what you want to avoid.

Obviously if you don't feel well then that is a difficult kettle of fish, and you might find that doing what the doctor/endo wants i.e. reducing dose helps a lot, a little, or not at all.

1 like

You've been really helpful, thanks a lot.


You may also like...