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Thyroid UK
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Afternoon fatigue

I was wondering if anyone has any ideas of how I can adjust my medication to help with tiredness in the afternoon? I'm on 75mcg of thyroxine.

I was diagnosed with autoimmune thyroid problems about 2 years ago. I have my TFTs checked every 6 months minimum and my TSH is well suppressed. I've also had my T3 checked and that was fine so I don't seem to have any problems with converting.

In a morning I feel pretty okay but late afternoon and evenings are a write off.

Has anyone had this and have any tips on what to do to improve it?

17 Replies

Normal, fine or suppressed in one individual's opinion might sound right but not necessary mean they are optimal.

Can you post your actual results?


Thyroid Function


FREE THYROXINE 16.43 pmol/L 12.00 - 22.00

TOTAL THYROXINE(T4) 92.5 nmol/L 59.00 - 154.00

FREE T3 4.36 pmol/L 3.10 - 6.80


Oh dear 😱, those results are definitely not optimal especially for people with Hashimoto's (autoimmune hypothyroidism).

And whoever said your TSH is "well suppressed" is so wrong.

The proper treatment is where your TSH is 1 or below with FT4 & FT3 above mid to upper range altogether with vitamin and minerals in optimal ranges.

Make an appointment with a GP and request a 25 mcg dose increase. Then retest it after 6-8 weeks with another dose increase until you reach above levels.

Also post any vitamins/mineral levels if tested so people can comment further.

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Your TSH isn't suppressed at all. It's much too high. Who told you it was suppressed? Your FT4 is below mid-range, as is your FT3. Most people need them up near the top of the range to feel well. And your dose isn't much more than a starter dose. You are under-medicated. No wonder you get tired.

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Yes, you could definitely do with an increase. I've just had an increase of 25mcg on the back of a tsh that was 1.53. I've just had the retests and I'm still within range but now nicely under 1.

My endo has always tried to keep my tsh under 1 - this is the levels that those without thyroid issues would be so we should be at that too :-)



You could post your thyroid results for a second opinion as to whether you're optimally medicated?

Otherwise you can think about the following.

You can check your vit levels (folate, B12, Vit D, Iron/Ferritin). Being low in any of these will cause tiredness. Many of us us hypos are particularly prone to deficiencies and these are often missed or ignored by docs so post these results if you have them also.

You could also think about the times it is happening and see if anything relates - Blood sugars often take a dip at this time of day and they are easily tested at home at various points during the day with a diabetic finger prick test kit - it doesn't cost that much for a three day review kit. There are things you can do to help stabilise these levels if turn out to be the problem.

Do you eat enough calories to cover your bodies energy requirements.

Also does it happen more often after you eat or eat specific things. For instance, do you skip breakfast and only start to feel tired after lunch. If you eat anything that you are intolerant too, it will have this type of effect. I worked out that if I skipped lunch, it was less likely for this to happen to me - this was only an experiment for a day here or there - I certainly don't mean for you to start skipping meals lol!!

I also had a sleep disorder until I gave up gluten and was always tired but a little worse after eating and always falling asleep on my desk more at this time. I would sometimes wake up a little more around 10pm and after some time of eating any food.

If none of those pick up anything, then you could maybe check your cortisol levels throughout the day as these are always cyclical in nature too.

This is all I can think about at the mo but hope it helps :-)


75mcg is a starter dose and i very much doubt its what you need

Get hold of your results because clearly something is not right


Thanks everyone. I did have an increase of my dose a while back to try to boost my T4 number but my TSH went to <0.01 so I went back to 75mcg. Is there a way to try to increase my T4 and T3 if my TSH gets too low?


It really doesn't matter if your TSH drops (as long as your Free T4 and free t3 are under the top of the range), although many GPs seem to get upset about it. TSH is not a thyroid hormone, it is produced by the pituitray to make the thyrpid output more hormones. If you have enough hormones, the pituitary knows that more TSH isn't needed.



It is possible to adjust your dose by as little as about 4 micrograms a day! If you are on 75 a day now, and added 25 one day a week, that would be just under 4 micrograms a day. You could, obviously, do that day by day - for example, alternate days take 75 and 100.

If you are willing to split tablets you can even that out even more. And one make (Teva) even offer a 12.5 microgram tablet.

It is not clear if you switched from, say, a 50 plus a 25 to a single 100 microgram tablet? Or two 50s. Or a 50 and two 25s. Some people find that the precise combination of tablets makes a difference. Many people find switching makes has an impact.

You could also choose to take your levothyroxine at bed-time. Some people much prefer that and do better on it.


Thanks for this - I hadn't realised that the half life of levothyroxine is as long as that but I makes sense. I had jumped from 75mcg daily to 100mcg daily but I see I could do it much more incrementally. I can see I need to take a bit more ownership and negotiate my care a bit more.

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Oh and I am already gluten free and I try to avoid too much carb in case of reactive hypoglycaemia.


Ah okay, I see. That's good advice. Thanks.


I think you should test for iron. I also don't think you should change your dosage without a doctor.


No no I wouldn't do anything without my doctor on board. Another thing I don't know about is antibody levels. Do they mean anything? Can I lower them in any way? Do high levels mean worse symptoms? What is a high level?

Mine are

Thyroid Antibodies

THYROGLOBULIN ANTIBODY *476.100 IU/mL 0.00 - 115.00



StewardsEnquiry I think you can see from the ranges you've put after the results what a high level would be, and your results certainly count as high :)

High antibodies confirm autoimmune thyroid disease aka Hashimoto's which is where antibodies attack the thyroid and gradually destroy it. The fluctuations in antibodies cause fluctuations in symptoms and test results and these 'Hashi's flares' can mean you swing from feeling hypo to feeling hyper. The flares are temporary and then you'll swing back to hypo again.

You can help reduce the antibodies by adopting a strict gluten free diet which has helped many members here. Gluten contains gliadin which is a protein thought to trigger antibody attacks. Supplementing with selenium L-selenomethionine 200mcg daily can also help reduce antibodies, as can keeping TSH suppressed.

Most doctors know little or nothing about Hashi's and dismiss antibodies as unimportant. However, due to the fluctuations it can make you feel unwell and may even mean you need a temporary adjustment to your thyroid meds. Read and learn about Hashi's because you will need to help yourself here.






Hashi's and gut/absorption problems tend to go hand in hand and very often low nutrients are the result. Unless nutrient levels are optimal then thyroid hormone can't work. If you've had vitamins and minerals tested, please post the results, with reference ranges, for comment, say if you are supplementing, with what and the dose. If not done then ask your GP to test:

Vit D





Thanks by the way for everyone taking the time to reply. I really appreciate your advice.

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