Thyroid UK
84,046 members99,034 posts

What is making everyone constipated???

Hi all, i've only just been diagnosed with hypothyroidism (only started meds 25g thyroxine 2 days ago) and am researching loads. I get constipated and bloated, tired and grumpy, have fluid retention and feel cold. I was hoping that once on a regular dose of thyroxine these symptoms would be reversed or what is the point in the medication. I'm confused as to why so many people are still constipated etc and taking lots of probiotics and other stuff. Do the meds not work? Do you have other illnesses as well as the hypo? I'm very confused right now.

17 Replies

Not sure how you have the impression everyone is constipated :-) I am not - but then maybe that is because I have Crohns and had loads of bowel removed. Constipation can be caused by LOW thyroid. Magnesium and VitC can alleviate the situation ....

Everyone is an individual so we all improve at a different rate. When you are optimally medicated you should feel better. Have you addressed the vitamins and minerals and had them tested ? Ferritin - B12 - VitD - Folate ? - all need to be optimal for you to feel well and for the Levo to work efficiently.

So keep on reading :-) Most of us are still learning after years of treatment - and that includes me !


I seem to come across endless posts about probiotics and i'm wondering if i need them, are the yakult drink thingies good enough or do i need to be buying stuff off the internet that i've never heard of and blending stuff lol. I was hoping that the symptoms i have will simply be reversed once i start the medication. I also take iron tablets and have VitB12 injections every eight weeks. I think i need slow down a bit and stop researching lol.


I think you need to research the Gut micro-biome - which is all about balancing the good and the bad bacteria. It is difficult to find the right pro-biotic for you - as again we are all individual. You could start with eating GOOD natural yogurt without added fruits and sugars and also certain foods like sauerkraut are good.

OK so you are taking Iron - was this prescribed by your GP ? It may not be the best type. Type Iron into the Search Box at the top of this page and read the experiences of others. You should take VitC I have read to aid absorption of Iron - but then again that is not ALL iron supps.

B12 injections - do you have Pernicous Anaemia ? I have read it is good to take a GOOD B Complex with B12 to keep all the B's in balance.

Low B12 and Low Thyroid often go hand in hand.

Levo/T4 is NOT a quick fix - so expecting 25mcg to reverse all your symptoms is an unreasonable expectation. It needs time and patience so keep on reading and learning.

Do you have Hashimotos ?


I do have pernicious anaemia, not been diagnosed with hashimotos, just underactive thyroid. I'm reading up on both at the moment. Will look into supplements and probiotics too. Thank you for your responses. I have a feeling this site is going to be very helpful. x x x x


Have you had your thyroid anti-bodies tested ? As PA is auto-immune then it is possible to have an auto-immune condition affecting the thyroid.

Thorne Research is a good B Complex - used by many here.

Have you had your VitD tested ??


No, i haven't had VitD tested or thyroid anti-bodies. I have pernicious anaemia and have injections of B12 and i am B rhesus negative blood group (don't know f thats relevant but i know it has something to do with antibodies lol)


So I would suggest that you have your VitD tested and the Thyroid Anti-bodies detailed above. Nothing to do with the Rhesus Factor. When you have one Auto-immune condition it is quite common to have another. I have Crohns and Hashimotos.


To begin with, levo is not 'meds' in the normal sense of the word. It is a hormone. It doesn't cure anything, it just replaces the hormone your gland can no longer make to keep you alive.

And, it's not just a regular dose of hormone that you need, it's an optimal dose. And a lot of people never manage to get on an optimal dose due to doctor ignorance. Plus, it can take a long time to find the right dose for you as an individual, because with hormones you have to start low and increase slowly, so as not to stress the body.

What you have to realise is that you have probably been hypo for a long time before you get diagnosed, for various reasons. One reason is that things happen so slowly with hormones, and the symptoms take a long time to make themselves noticable. Plus when the thyroid starts to fail, the adrenals take up the slack, which means an even longer time before you notice something is wrong. In that time, some permanent damage can be done. And even if there is no permanent damage, symptoms that have taken years to manifest themselves, can take an equally long time to resolve.

But, the main reason for taking the levo is that, without it, you will die.


So would you say its just a waiting game for now. A bit of trial and error with doses until it gets to the optimum dose? My Serum Free T4 level is 11.1 and my Serum TSH is 1.98. Currently on 25mg as a starting dose and have to have my bloods done in 8weeks. I guess this is normal for someone newly diagnosed.


More or less, yes. But, if you can get away with it, testing in 6 weeks would be better.

Yes, patience and trial and error, they are the key words. You cannot rush anything hormonal, or you will find yourself back at the beginning.

Of course, 25 mcg is not going to make you any better, and could even make you worse! Your doctor would have been kinder to start you on 50 mcg - unless you're about 90 and have a heart condition - in which case, they probably wouldn't bother to treat you at all! But, all things pass, and soon you will find yourself on 50, and then 75, and hopefully continue to increase until all your symptoms are gone.

In the meantime, learn about your disease, read and research and talk to people and ask questions. After all, somebody's got to know what they're doing - and it certainly won't be your doctor!

Oh! And by the way, when giving results, always, always give the range. The numbers on their own - apart from the TSH - mean nothing. :)


One of the effects of hypothyroidism is that the body "dries out". So people have dry eyes, mouths, lungs etc. They also have reduced stomach acid, which I think of as part of the "drying out".

With reduced stomach acid the stomach is unable to kill off pathogens as well as it should do, food doesn't get broken down properly so nutrients can't be extracted well and nutritional deficiencies develop. Also, low stomach acid causes heartburn, indigestion, acid reflux.

With all of the above happening the gut bacteria in the digestive system alter, gut damage can occur.

Hypothyroidism can take decades to be diagnosed in some cases. It would be impossible to fix all the damage that hypothyroidism does to the gut. All we can do is eat sensibly, supplement where necessary, keep our fingers crossed, and hope for the best.


Get your blood test first thing in the morning, and don't take your Levothyroxine for 24 hours before the test. That way you are less likely to end up under-medicated.

It's quite normal to feel no better, or slightly worse on a low dose of Levothyroxine as your thyroid, which has been struggling, takes the opportunity to have a bit of a rest. When you are on a high enough dose you will stop feeling cold and probably be less constipated too. 25mcg is a teeny dose. Most people end up on something like 100-200mcg if their thyroid has stopped working altogether, sometimes more.


Gut motility slows with hypo. Everything slows, so that's not surprising. V common symptom and perhaps those who don't have it have a second condition. Can take ages for treatment to fix, and some find it only goes with some added t3. Can take a year to improve.

You should get your antibodies tested for hashis.


>Do you have other illnesses as well as the hypo?

I was taking Nifedipine for high blood pressure, and hadn't realized it was responsible for worsening my constipation!

1 like

Make sure you always take your Levo on an empty stomach and no food or drink (other than water) for at least an hour after.

Many take on waking, but lots of us take at bedtime, can be more convenient.

There is some recent research suggesting taking at bedtime may be more effective.

Don't expect a quick fix. Stick at a dose, don't skip doses (get a weekly pill dispenser to help remind you). As others have said 25mcg is tiny dose, but we have to step up slowly or body can't cope with the change.

Increases are usually in 25mcg steps. With blood test repeated 6-8 weeks after each increase.

Lastly always stick to same brand of Levo different brands give different effects for apparently the same dose

Long research article - final conclusion paragraph below

"In conclusion, bedtime intake of levothyroxine in our study significantly improved thyroid hormone levels. This may be explained by better gastrointestinal bioavailability at night or by less uptake interference by food or medications. As shown in this study, bedtime administration is more convenient for many patients. Clinicians should inform their patients about the possibility of taking levothyroxine at bedtime. A prolonged period of bedtime levothyroxine therapy may be required for a change in QOL to occur."

1 like

Don't forget some iron supplements can contribute to constipation. However I find that magnesium supplements get things moving again! Also, as others have said it's early days, you are on a low dose of Levo, so it will take time for things to improve.


Everyone will react differently to levo. When my new GP put me back on it last year some of the symptoms improved within two days (double vision), but others took longer, and some (digestion) took months and an increased dose. I was started on 25mcg but have now been increased to 100 mcg. As has been mentioned here, my doctor said I may well need a higher dose but I had to start off low and increase gradually as going straight in at 100 could be dangerous and needed confirming by blood tests as well as by how I feel. He also said it would take at least twelve months, probably longer, for my body to repair all the damage done after my previous GP took me off the levo when he said I "was cured and didn't need it any more". A dicey thyroid can affect everything. I went from running a marathon (not very fast as there were a couple of mountains to climb, a tarn to wade and rock face to descend) to taking half an hour to get down the stairs in a morning due to the pain in my Achilles, I had double vision, I oscillated between constipation and, erm, the opposite, my short term memory was atrocious and so on.The list of symptoms is almost endless. It will take a while but you will recover in time.


You may also like...