Morning diarrhoea - I don't think I am over-medicated. Could it be sensitivity to the thyroxine or the fillers?

I was diagnosed hypothyroid April 2012 and started on 25mcg levothyroxine. Dosage gradually increased and have now been on 100mcg for just over two weeks. I've become aware that diarrhoea in the mornings has become a problem, to the extent that I am reluctant to go out in the mornings. By after lunch it has cleared up. I take my levothyroxine as soon as I wake up, wait 40 minutes before eating and drinking, but often need to go even before breakfast. I've been trying a gluten-free diet but only 4 days so far - doesn't seem to have made a difference. It has to be something to do with the levothyroxine. The obvious answer is that I am over-medicated but my pulse is normal, I don't feel any different and I haven't lost any weight. I've just ordered a test kit from Blue Horizon today so I have something else when I see my GP next week. In the meantime, any ideas?

27 Replies

Dairy allergy? My endo got me to give up all dairy... it worked immediately...

If you've been hypo for a bit and maybe have adrenal issues it can make you sensitive to any food stuff... the idea is to give up dairy and wheat for 10 days and then add them back in really really gently.. and maybe you can get your system to recover.. I didn't.. had an icecream on holiday and spent 3 days on the toilet!

However.... if you DO have a dairy intolerance.. the fillers in Levo and T3 will make you ill.. and you're better off with NDT.. though if you're in the UK.. you will have serious problems trying to get it...

Good luck

I've tried in the past giving up dairy products (for a different reason) but don't think I have a problem with them. It's mainly milk in tea anyway - I don't have a lot of cheese or yogurt. I see what you mean about the link between dairy intolerance and the lactose in the filler but I don't think it can be that as I have milk in tea later in the day but no diarrhoea.

Hi penstemon,

I had the same problem and I know the horrible feeling of being afraid to go out in the morning. Found a very low fibre diet helped but the issue didn't resolve until my levo. dose was reduced . Makes it seem certain that levo. is the problem. Hope you get sorted

Thanks. It helps in a way to know someone else has had the same thing. I am fairly certain the levo is the source of the problem because of the timing. I'm considering reducing my dose even before I see my GP.

I had the same problem for a long time. I'm hyper so I think initially my Endo expected me to have this symptom. However, I was still experiencing this when my medication had made me hypo, and my Endo was expecting the opposite. I had already tested negative for Coeliac, so he tested my adrenals, they were fine. It can also be a symptom of anaemia, and this is when he agreed to do the MMA test for me as my serum B12 was normal - my MMA was not normal and I was diagnosed B12 deficient. As it happens, my folate was below range, and my ferritin (iron) was low normal. As soon as I started B12 injections and folate supplement the morning diarrhoea stopped. It didn't totally resolve my stomach symptoms so I also gave up gluten. Both these things together have made a massive difference to me.

So I guess what I'm saying is you have to find out by trial and error what is causing your symptoms. If you think it's the Levo you could try taking it at a different time of the day and see if the stomach problems change time as well. If that doesn't help, then the gluten free diet might be the answer given some more time. If it doesn't, then as suggested above it could be dairy. But just make sure you're not anaemic - iron, B12 or folate. And see if you can get your adrenals checked.

Gosh, I hadn't even thought of B12 or ferritin. As you say, it's trial and error but it's really helpful to have input from other people to put a different perspective on it. I will carry on with the gluten-free diet and see what happens but will also ask GP about B12. I didn't think I had any other symptoms of anaemia. Thanks.


I have the same problem but my B12, iron and folate are good. I have tried the low gluten diet and it made a little difference but I have not thought about low fibre. I have infact increased fruit and vege and bought a very high fibre bread and my diarrhoea is worse, never made the connection( if there is a connection, this problem seem to be a tricky one as there can be so many causes)

The other thing that can upset your digestive system is candida overgrowth.


Yes, it's hard to get things right, isn't it? I suppose whatever change we make upsets something else. I know about candida so don't think it's that. Things slightly better today so perhaps it's the gluten.

And that's a good idea, to take the levo at a different time of day. I hadn't thought of that.

Research has found that night-time dosing is better than a.m. If you did take it at bedtime you would have to have eaten two hours before. This is an excerpt from the link below:-

You may want to talk to your practitioner about changing the time you take your levothyroxine (i.e., Synthroid, Levoxyl, Levothroid, Unithroid, Eltroxin) to bedtime, versus morning. And if you decide to change to taking your thyroid medication in the evening, be sure to have your thyroid levels evaluated -- six to eight weeks is a reasonable timeframe -- after you’ve made the switch. The blood test results, along with any improvements or worsening of symptoms, will help you and your doctor to determine if you need to adjust the dosage or timing of your medication.

Thanks - night-time would certainly be possible. I think I should give the gluten-free diet a few more days first, though, to see if that's a factor. Otherwise if I try two things at once and it clear up I won't know which one worked.

Yes, that's a sensible thing to do. I hope you find the solution soon.

Thanks. All these responses have been so helpful. When you're in the middle of something it helps to have input from someone else.

Have had this for years, but no levo and vegan (so no dairy). I think it might be adrenal/cortisol related.

That sounds awful if you've had this for years. It's so disabling. I hope you can find a solution. I'll bear the adrenal aspect in mind although I feel quite well (apart from the obvious!).

It used to be worse, so getting B12 right might have helped. It doesn't really bother me so much now as I just get up an hour earlier to allow for it.

I have had to cut back my dose of NDT in this hot weather as I was having a few symptoms of over medication (sadly not weight loss though :( ) Just wondering if the hot weather could be affecting you too? Xx

Unfortunately, I don't think so (it would be nice if it was because that would be simple). This diarrhoea thing has been there for quite a few months but I was sort of ignoring it - I thought it might just be something to do with my thyroid. I agree it's only recently it#s become a real problem but I'm afraid that started while the weather was still cold and grey.

Hi Penstemon, I have just read this thread and it sounds identical to my daughters problems ... did you ever get to the bottom of it?

Hello, I worked out in the end it was a combination of things. First, I think I was very slightly over-medicated as my GP had just increased my dose to 100 mcg per day from 100/75 mcg on alternate days, and the weather had got hotter so I perhaps didn't need the higher dose at that time. We've now agreed I will increase to 100 every day in September and probably lower it to 100/75 in March. The reason I think I was so sensitive to the increase was due to having not been treated for my underactive thyroid for so long - it seems to me that the longer you have needed treatment but not had it, the longer it will take for your body to adjust to the thyroxine. I had at that time been on thyroxine for about 18 months. Second, I think my vitamin D was low, as I tested it and it was definitely insufficient. I took the recommended dose of vit D for six months and tested again and am now fine, although I will check probably every 18 months or so. I think the low vitamin D meant my system was not working properly. I also changed to taking my levothyroxine at night instead of in the morning and found this suits me better. So any of those three things could be a factor in your daughter's case, or it could be something entirely different. I hope you manage to find a solution.

Thanks for taking the time to reply ... since messaging you we have had another doc visit and after nearly 2 years of constant diarrhoea my daughters doctor has now suddenly decided to take it seriously .... seems he wants to be sure it really is the levothyroxine causing it so has told her to stop taking the levo completely for the next 6 weeks! Sure enough here we are 6 days later and diarrhoea seems to have eased .... but now we are just waiting for all the hypo symptoms to come back!!. It seems a pretty drastic way to find out the cause of diarrhoea and I don't know what he plans to do if it is, as I have always suspected, a side effect of the levo. Her vit D was tested a month ago and was fine and she has always taken her meds at night anyway as I read its best not to take near food so this has always seemed best. Wish I could wave a magic wand and make the poor girl better again .... you all have my complete admiration for just keeping going day after day, it seems nobody really understands thyroid probs :(

I agree it's drastic just to stop the levo like that. There are other threads where people say they are sensitive to the fillers used in the levothyroxine so I hope your doctor doesn't decide it's the levothyroxine itself and stop her treatment. As you say, the result of stopping will be the return of symptoms.

Hi - I'm interested in knowing how this worked out for you. When i was taking Levothtroxine, loose stool was a daily occurrence. Turns out it has a carrying agent (filler) I'm allergic to. Now i take Armour. I'm better, but i am hyoer sensitive to certain foid ingredients, in particular soy. I hate to cook. I've had to learn how. Soy is in everything. I now bake my own bread, make my own ice cream (the fake stuff made from almind milk isn't bad) and eat Enjoy Life chocolate bits when I want chocolate. All American chocolate has soy lecithin in it which they don't list. Amy's so-called healthy meals don't list their soy, but except for tge Mac and Cheese, all their items have it. Kroger brand foods all have soy except frozen plain vegetables. At a restaurant i'm safe eating cottage cheese and fruit and a bowl of lettuce. Many fowl meats are tenderized with soy - i have to be careful at the supermarket. Canned tuna is now packed in soy oil.

Now it seems I'm unable to eat certain homemade cookies or candies (made by me) which puzzles me. I'm okay with Snickerdoodles, but cookies with Hershey's cacao powder seem to cause bowel problems, as does wine.

Armour is better but not perfect, for me. :-(

Hello. Glad you are doing better on Armour. In my case I found it was Actavis levothyroxine which was causing the trouble (I'm in UK but looks as if you are in US so presumably different brands). I now make sure I get Mercury Pharma levothyroxine and it seems to be all right. I don't know if it was one of the fillers in the Actavis or whether it was the absorption rate. As to sensitivity to certain foods, I am sure when your thyroid doesn't work properly it can cause these. I developed a sensitivity to chocolate around the time my thyroid went wrong. Not an essential food so not a big problem.

Hi just looking through posts as i am having morning bottom sickness soon after my levo and way before breakfast ,but 6 days ago i had food posioning so not sure if my tummy is still recovering ? and not sure if it helps but i had a different brand a few months ago and i had bad tummy every morning and the turned out to be Mercury Pharma brand it contains acacia powder that they use as a filler once i changed brand it went :) wish it was that simple this time ,hope your both sorted now ? xxxxxx

Mine is fine now, thanks. I'm now on 100 mcg per day with no problems. Just needed to take it slowly. Also the vitamin D. It does sound as if your problem may be the fillers so I hope you can find a solution.


I suffer from this. Actually I'm lucky if I am ever solid. I have been like this ever since I had my gall bladder out but it did get worse a few month back. I've been checked for infection and cealiac (can't spl it)

I also take my Levo at night and it makes no difference to me.

Doc said he is thinking about sending me to a specialist because of how often I'm in the loo.. sometimes it's the second I wake. Sometimes I go for a wee and it comes away from me..

I do know how you feel it's not nice. I also suffer from piles and I don't know why cos I'm never constipated.

Also must add I'm still not at my optmol levels.

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