Reduced Levothyroxine Dose - Are my symptoms no... - Thyroid UK

Thyroid UK

120,899 members140,853 posts

Reduced Levothyroxine Dose - Are my symptoms normal?

TiredMummy profile image

Hello everyone,

Just looking for a little bit of assurance from someone that what I’m experiencing may be temporary & what I might be able to do about it.

I’ve been on 100mcg of Levothyroxine for well over a year (was on 75mcg prior to that) but, due to a recent blood test (I did it myself via Blue Horizons), my GP has reduced back down to 75mcg. The rationale when looking at my test results seems sound but I reduced the dose on Saturday morning (so today is day 3 on the reduced dose) & I feel very hypothyroid! I feel very dizzy, like I might faint, spacey, exhausted, sweaty, bit depressed and brain dead (I had to read sentences 4-5 times at work today for the info to sink in!).

Test results as follows:

TSH - 0.01 (0.27 - 4.20) - LOW

T4 total - 121.0 (66 - 181)

Free T4 - 31.10 (12.0 - 22.0) - HIGH

Free T3 - 4.59 (3.1 - 6.8)

Anti-Thyroidperoxidase abs - 153.0 (<34) - HIGH

Anti-Thyroglobulin Abs - 117 (<115) - HIGH

I’ve got an important meeting tomorrow morning & im thinking of cutting a 25mcg in half & taking half of that along with the 75mcg (87.5mcg in total as opposed to 75mcg). Basically I’m wondering if I should reduce the dose slightly less than 25mcg to start with (as my body is not coping with the 25mcg reduction)....or whether I should just tough it out & see where i am in a few weeks time? I wonder if this would be a bit gentler on my system?...Whatever approach I take, I will of course have my bloods done again in 6 weeks time.

Thanks for reading & any help, ideas or advice is very much appreciated!

21 Replies

Your symptoms are more than likely from low T3 - it was low before your doctor reduced your dose, it'll be even lower now. Although, to be honest, I wouldn't have expected you to feel the reduction so soon. Are you sure you don't have some sort of flu bug, or something?

Strange that high FT4... How long a gap did you leave between your last dose of levo and the blood draw? Looks as if you only left about 3 or 4 hours. If the FT3 were also high, I would say it's due to the Hash's rather than the levo, but your FT3 is quite low. Do you have a blood test from when you were on 75 mcg, for comparison?

I would love to know what your doctors reasons were for reducing your dose. :)

TiredMummy profile image
TiredMummy in reply to greygoose

Hi Greygoose & Slowdragon thanks so much for responding. Interesting that you think my T3 is low...? In the range, it looks ok to me so do you think it’s low in comparison to the amount of Free T4 or do you think the normal reference range the lab uses are low? I have a confirmed T3 conversion problem so I guess I shouldn’t be surprised but as I am showing some T3 (think it was around the 2 mark when I was on 75mcg).

Definitely don’t have a bug, I know this feeling well & it feels hypo. I’m just wondering if it’s temporray & I should battle though or up the medication back to 100mcg. I guess my doctor wanted to reduce it as he wants to protect me from side effects of too much thyroxine like osteoporosis..?

I took the Levothyroxine at 6am & had the blood test at 7:40am and it was fasted. I’m having a vitamin etc check soon so will see what that comes back as. I’m already gluten free & have been for years & currently trying grain free.

greygoose profile image
greygoose in reply to TiredMummy

So, you took your levo 1 1/2 hours before the blood draw? Well, that's why it's high, then. But, that wouldn't have affected your TSH.

If that's what your doctor is thinking, he's wrong. Thyroxine doesn't cause side effects like osteoporosis, even if it's high. It's more or less inactive, it's a storage hormone. But, you said 'The rationale when looking at my test results seems sound', so I thought he'd explained why he was reducing your dose.

TiredMummy profile image
TiredMummy in reply to greygoose

I think to be honest we agreed I should try reducing the dose because of the lab results. So based on my TSH you wouldn’t have lowered the dose in your opinion? My GP will have no problem letting me increase the dose back to 100mcg if I can explain why it shouldn’t I.e. if my TSH is fine & the free T4 is that high because of the blood draw timings? But is my TSH fine do you think?

greygoose profile image
greygoose in reply to TiredMummy

The TSH is not the most important number. The FT3 is, and that's too low to make you well. Very often, we have to have the TSH low in order to have enough T3 - or, more accurately, when we have enough T3, the TSH has to be low. Try and increase it, and the FT3 will drop and you will feel worse. And, as you said, the FT4 is so high because you took your levo too close to the blood draw, so all you tested was the dose you just took. Not the normal level of circulation T4. So, forget the TSH, there's nothing you can do about it, anyway, not if you want to be well.

TiredMummy profile image
TiredMummy in reply to greygoose

Ok, that makes sense to me. It was worth trying to reduce it but I can tell it is NOT working & from experience I can feel that this will only go one way if I continue on the lowered dose. I’ve been there before & it’s devastating to myself & my family! I will increase the dose back up to 100mcg & convince my doctor to change the dose back. Luckily I have a very nice doctor & don’t think getting it changed will be a problem. He let me have T3 on the NHS for example after seeing a private doctor. I didn’t get on with T3 at the time (it made me feel worse for some reason) but I may ask to re-try it in the near future to see if it now has a better effect.

SlowDragon profile image
SlowDragonAdministrator in reply to TiredMummy

For T3 to work vitamin levels must be optimal. It needs to be started extremely slowly and often needs to be taken in split doses through the day.

Have you had DIO2 gene test that you know you have conversion issues?

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l.

Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor

 please email Dionne at

Professor Toft recent article saying, T3 may be necessary for many otherwise we need high FT4 and suppressed TSH in order to have high enough FT3

Thank you Slowdragon I will email & show my GP. No, I haven’t had that genetic test but worked with a private doctor, Professor Schulte, & he told me I had a T3 conversion problem. It’s because of him that I tried T3 in the first place but as I said, I never got on with it. Interestingly, my attention is turning to gut (I’m on week 6 of the GAPS diet), vitamins & adrenals.....I will keep you posted but already feel a bit more human since taking 100mcg Levo at 5am this morning. I couldn’t wait any longer as my body felt so desperate for it! Hopefully I’ll function ok for my meeting today (it’s only with the CEO which is typical!) had bad insomnia last night thanks to the reduced Levo dose. You live and learn as they say! Thanks so much ladies for all you support it is HUGELY appreciated!!

Apologies, forgot to the genetic test a saliva test? It looks like this test might be worthwhile for would perhaps clarify things a bit.....

SlowDragon profile image
SlowDragonAdministrator in reply to TiredMummy

Yes it’s a spit test. Quite a lot of spit required. So allow time to fill the pot - 15-20mins

Post off and results take 2-3 weeks

You have to pay for counselling as well on any DNA test so that bumps price up a bit

But it definitely helped my argument to get my T3 on NHS

Though not all CCG’s honor it yet, it’s getting more accepted as time goes on

Your free T4 191% of the rage and your Free T3 is only 40.27% of the range. So ether you just took your levo a few hours before the test or you are really, really, really bad converter. Most people need free T3 to be at least 66% of range to feel well. So you need a higher dose of levo or some T3 added.

Thank you! Those percentages are incredibly helpful!

P.S. I stupidly took my Levo 1hour & 40 mins before the test. You live and learn!!

SlowDragon profile image

As greygoose says, your FT3 was already low. Your results show poor conversion

All thyroid tests should ideally be done as early as possible in morning and fasting. When on Levothyroxine, take last dose 24 hours prior to test, and take next dose straight after test. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, GP will be unaware)

Is this how you did the test?

You have Hashimoto's also called autoimmune thyroid disease diagnosed by high thyroid antibodies, low vitamins are extremely common

Have you had vitamin D, folate, ferritin and B12 tested at all? Add results and ranges if you have them

What supplements do you take?

Hashimoto's very often affects the gut and leads to low stomach acid and then low vitamin levels. Low vitamin levels affect Thyroid hormone working

Poor gut function can lead leaky gut (literally holes in gut wall) this can cause food intolerances. Most common by far is gluten.

According to Izabella Wentz the Thyroid Pharmacist approx 5% with Hashimoto's are coeliac, but over 80% find gluten free diet helps, sometimes significantly. Either due to direct gluten intolerance (no test available) or due to leaky gut and gluten causing molecular mimicry (see Amy Myers link)

Changing to a strictly gluten free diet may help reduce symptoms, help gut heal and slowly lower TPO antibodies

Ideally ask GP for coeliac blood test first

Thanks very much for all this helpful info Slowdragon. Greygoose has also highlighted the timing of the blood draw should have been a lot later after taking my Levothyroxine (took Leo at 6am & blood draw was only at 7:40am). I’m just wondering if you also think my TSH & free T4 is fine in light of this & you wouldn’t have recommended lowering my Levo dose!

SlowDragon profile image
SlowDragonAdministrator in reply to TiredMummy

All thyroid tests should ideally be done as early as possible in morning and fasting. When on Levothyroxine, take last dose 24 hours prior to test, and take next dose straight after test. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, GP will be unaware)

Many people have complex mix of issues.

Vitamin deficiencies

Gluten intolerance



All affect results

TSH is often suppressed. Most important to not take Levothyroxine before test to get accurate FT4 result

It could be a flu type bug, so difficult to identify properly in the context of long term condition and dose change. I’d try to keep on a stable dose whatever you decide.

TiredMummy profile image
TiredMummy in reply to Aurealis

Thanks Aurealis, yes I know what you mean in that this could be a bug or something but I really don’t think it is. I’ve felt like this before & it’s always when my dose is reduced. This never seems to work for me & I end up going back up to the original dose! It’s just a bit confusing when you hear one thing from doctors and another from patients when it comes to dosing advice!

Yes, think you have to listen to the advice but ultimately make up your own mind based on your instinct. I’d be poorly on levels suggested by some on this site, and I’m poorly if test results are in range. It’s all a big joke (not) really.

Hello everyone,

I just wanted to briefly update you on this. After following the very helpful advice from you guys, I went to my GP this morning armed with a print off of Professor Toft’s article. I explained how the results just showed the dose I had taken and how it demonstrated poor T3 conversion & he has agreed to increase my Levothyroxine from 100mcg to 125mcg initially. I will get my bloods re done in 6 weeks (remembering to get the bloods draw done first thing in the morning PRIOR to taking Levothyroxine!). We will then review & see if if we need to increase to 150mcg.

I was thinking (to keep costs down a bit) to get the first set of bloods done on the NHS (when I’ve been on 125mcg for 6 weeks) but the problem with this is it will only show the TSH & if I’m lucky the T4. I was just hoping I could decide at that point based on my symptoms if I needed to increase Levo to 150mcg and then do a private test after being on this for 6 weeks. Im just trying to avoid having to pay for two private tests but perhaps there is no other way....?

I forgot to add the obvious!.......the reason I am not pushing to get T3 as medication is because I have tried T3 quite a few times & I have never got on with it as it has always made me feel significantly worse. Having read Dr Toft’s article I’m beginning to wonder if that’s because my body wants to convert on its own but it just needs more T4 to do the job.

I see this next phase of upping T4 as part of my ongoing journey & I can always re-address if this plan doesn’t work. In which case I think I would take the genetic test Dr Toft refers to and if appropriate re-trial T3.

You may also like...