Thyroid UK
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L-carnitine for thyroid - HypER or HypO ?

Yesterday I purchased a few vitamins/supplements recommended on here for patients with Graves/Hyperthyroidism. Having just "googled" what L-Carnitine is, it's uses, side effects, interactions and warnings - it does state that it is known to help with some symptoms of an over active thyroid HypER (heartbeat, nervousness and weakness). However, it also states that it could make symptoms of an under active thyroid (HypO) worse ! To be honest I'm not 100% certain of what I am at the moment (apart from a basket case ;) ) I was diagnosed Graves/HypER, have been HypO and it has been suggested on the forum that I could have Graves and Hashimoto's running in tandem and I intend asking to be tested, however, my next appointment isn't until 30th December. Should I take the L-carnitine or not ?

Also, if I do have Hashimoto's too, what then? Are the meds the same meds, are the options the same as I have been given now i.e. Continue on the meds with titration or RAI or Surgery ? What next ?

Thank you in advance for advice


7 Replies


It's not uncommon for Graves patients to also have Hashimoto's antibodies but it's the Graves antibodies which will be most active causing hyperthyroidism. Autoimmune conditions aren't treated but the conditions caused are ie Graves hyperthyroidism is treated with Carbimazole, and Hashimoto's (without Graves) causes hypothyroidism which is treated with Levothyroxine.

Overmedication of Carbimazole lowers thyroid levels too much but that temporary hypothyroidism resolves when dose is reduced.

So, having established you are hyperthyroid, L-Carnitine may be helpful.


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.


Thank you for your response, once again very much appreciated. I am still finding the use of the medications and what they are actually do difficult to get my head around - if reducing the dose of Carbimazole resolves HypO, why did the Endo prescribe going back onto 100 micro grams Levothyroxine instead of reducing the dose of 40 mg Carbimazole ? (my GP stopped B & R to see how my thyroid reacted and within less than a week HypeR symptoms returned with a vengeance and I started back on 40 mg Carbimazole without first consulting my GP as I knew this would reduce the symptoms as it did when I was first diagnosed and was given this dose of Carb by my GP whilst waiting for my appointment to see the Endo).

I didn't used to be "slow on the uptake" of anything but these days..............oh boy......... :(


CC251254, 40mg Carbimazole will block your thyroid and cause hypothyroidism. 100mcg Levothyroxine will replace the low thyroid. That method is known as block and replace. Different endos have different protocols to treat hyperthyroidism. Some like to titrate Carbimazole while others prefer block and replace.

Low thyroid levels can cause slow thinking. It should improve when you are optimally dosed.


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 personally do not think you have both Graves and Hashi. I think the confusion may have arisen because the Carbimazole made you hypo, not Hashi.

It is so easy to go over with antithyroid medication and it is a juggling act to get the correct dose. It's bad enough with just Carb, but even worse, in my opinion, with two medications, as in B&R. And obviously, everyone is different and needs a different dose.

Carnitine is known to help with hyperthyroidism and they recommend around 3000mg daily. I took it in the early days, desperate to find something natural to help, it didnt work. I also tried Lemon Balm, Bugle and Motherwort, also known to help. But, I think, at the time I was hypo because of a too high dose of Carb and that's the reason they didnt help.

If I could go back and know the things I do now I would sort out my diet, go gluten free, maybe dairy free. I would also try the above natural alternatives first. If they didnt work I would have started on a lower dose of Carb and titrated quicker (I did it very slowly and gradually because I wanted to know how each dose affected me and had no idea how large or small a drop I needed to do)

My Endo wasnt really much help. All she wanted was to get me to have RAI or surgery then refer me back to my GP. I dont think she bargained on my determination not to have it that way! :)


Hi, many thanks for your response to my post, I am very grateful for any input.

My Endo isn't much help either, that said, I have only seen the same specialist twice in about 7 appointments. The last one I saw was foreign and could hardly understand anything he was saying apart from him suggesting I think seriously about RAI (so that I "WILL BE NORMAL AGAIN" (?? HypO isn't normal in my opinion). However, I AM realising that many Endos DO push patients into RAI or surgery because being HypO is easier for them to deal with (not the patient who is suffering from being HypO). When I see him again on 30th December, I will be pushing for another chance at B & R. In my opinion, my B & R was stopped by my GP at a stage when it should not have been as I was complaining of HypO symptoms at the time and my TSH was 5.15 with a range of 0.34 - 5.6 and I now understand that a TSH of above 3 is HypO. My T4 was 13.4 with a range of 7.5 - 21.1 and I now understand that the T4 should be in the upper quadrant of the range, so in my case 16 or 17 ? Since that time (July) my blood results for TSH and T4 have been "off the scale" for August and September with October being slightly better results.

I hadn't realised that the recommended dose for L Carnitine was so high - I only bought 500 mg ?

I have started to feel a little better this week than I have for quite some time but I'm thinking that may be the meds kicking in again now rather than the vitamins as I've only been taking those since Sunday.

I'd rather be pregnant and have to go through labour than have this disease, at least there is an end to labour AND a precious gift :)



I agree about the baby thing!! :)

The recommended dose of Carnitine is actually 2000 - 4000mg but I have read that too much can make your body 'odour' a bit fishy. I have commented on that on this forum and those on the supplement have said they didnt suffer that, so maybe a certain brand or it does something to certain people?

Sorry, without rereading not sure how your B&R was done. But, generally, you take the two medications for about 18mths. The Carbimazole dose stays the same and its the Levo that is adjusted.

One of the problems I had was the Endo would insist on going by levels only, as if I didnt know how I felt!! I got up to 125mcg of Levo and still felt hypo.

I prefered the titration. I felt it was more 'natural' , but looking back I should have started on 20mg instead of 40mg and reduced quicker.

Some members say that you should be tested every 2 -4 weeks but I did not feel the full difference of a dose change for 8 weeks (although there was a very small difference in the first week)

I also have to say that some sufferers do well after having RAI (but not if you have TED, which I do) or surgery - we dont always hear about the successes on this forum! But I will never have either done and would advise that lots of research is done before going down that road, as there is no way back.


My B & R lasted for approx 20 months starting with 40 mg Carbimazole and 75 micrograms Levo. After about 6 weeks the Levo was increased to 100 micrograms and that's where both meds stayed at for the next 18.5 months. When the Endo put me on B & R he said he told me that was his last appointment with him and he was "passing me back" to my Medical Practice and my GP would monitor the me (arrange for 6/8 weekly blood tests). I received NO 'phone calls, letters etc for appointments for blood tests/check ups whatsoever for that 18.5 month period that I was on B & R. I went to see my GP a couple of times because I wasn't feeling 100%, blood tests were done and of course was told that my blood results were in range. When I made an appointment to see my GP last July because I had a few HypO symptoms, she dismissed the symptoms I was feeling (feeling extremely cold and tired all the time, anxiety and breathlessness) because my blood results were in range and stopped the B & R medication completely. Within a week I was in a heap on the floor in town after suffering such a bad attack of HypeR, going so light headed because of the severe heart pounding/speed and couldn't breath !

Anyway, I am going to stick to my guns and go for another shot at B & R or titration at the end of December and hopefully from there to remission !

Are you now in remission ?


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