Levothyroxine Dosage Adjustment: Will someone... - Thyroid UK

Thyroid UK

118,518 members137,442 posts

Levothyroxine Dosage Adjustment

Biloxi profile image

Will someone please help me figure out how to adjust my levothyroxine dosage?

I'm currently taking 100mcg, and I keep having heart palpitations. 88mcg was too little for me (TSH was around 8 on a 2-6 scale), that's why I'm on 100mcg. I don't want to go in to get tested, I'd rather the virus calm down some!

How would I do it?

Cut one in half one day a week, skip a day,...?

Your advice is greatly appreciated!!!

43 Replies

You can get heart palpitations because you are not taking enough levothyroxine too.

It is difficult to judge on TSH alone.

Biloxi profile image
Biloxi in reply to Lalatoot

I moved up to 125 mcg and it got worse. When I moved back to 100mcg, it stopped for about 2 months or so. It's been coming back intermittently, but now everyday.

It happens when I'm standing, sitting, laying down, breathing in, after eating, walking, and I think I feel it when jogging but I'm not sure. Do you think it could be the manufacturer? I'd go with name brand, but it's 10x more than I pay for generic.

Lalatoot profile image
Lalatoot in reply to Biloxi

You really need to know your ft4 and Ft3 levels to be able to judge.

dblsr profile image
dblsr in reply to Biloxi

Wow I could have written your post my doctor decided to put me on 88 micrograms and then every Sunday take take 1 and 1/2 pills I am feeling really good right now I have had no palpitations I will getting my blood work done again in July but I think I am on exactly what I need to be on right now I hope you can get yours figured out. My body had exactly the same reaction to the 100 micrograms, and on 88 micrograms my TSH was 8 so the doctor wanted to put me back on 100 I refused to do that so we are working on taking just that little bit more.

How long have you give the 100 dose? I had palpitations at the beginning of all of my doses..they have gone away now I’m settled on 100 tho

Biloxi profile image
Biloxi in reply to HashisKate

With me, it stops when I change, then starts up again! So weird.

Do you take it on schedule everyday? Like, for example, 7am no matter what?

Sometimes I take it at 6am, sometimes 6:30am, sometimes 7am.

HashisKate profile image
HashisKate in reply to Biloxi

No I don’t. I take it went I wake 6-7am can be anytime in between that hour. Used to take it even earlier when I was working as I can’t bare getting out of bed unless I can have a coffee, and as we all know you must leave an hours gap! I have never noticed any ill effects taking it a little bit earlier / later. I do however intermittently suffer with bouts of palpitations. I have done since I was a teenager (I’m now 35). Aside from upping my dose and experiencing them then for a week or two, I don’t think the intermittent ones are related to my thyroid. Sorry I can’t help more x

Biloxi profile image
Biloxi in reply to HashisKate

That helps, thank you! I'm not alone and it seems somewhat normal. It just feels scary sometimes.

HashisKate profile image
HashisKate in reply to Biloxi

It’s definitely worth investigating. I am confident because I had it invested by cardiology when I was 19 😊 x

flo72003 profile image
flo72003 in reply to Biloxi

Maybe you can try to take it in the evening. Or split the dosage between morning and evening. Just make sure , that you take it at least 2 hours after you have your dinner.

You really need your bloods testing again to know whether you are under or over-medicated - free T3 and free T4 as well as TSH - but in the meantime, there are various options ... you could take some levo in the morning and some in the evening, so you weren't "flooding" your body all in one go; or split a tablet and take a bit less one or two days a week. I wouldn't recommend taking nothing on a given day.

Biloxi profile image
Biloxi in reply to fuchsia-pink

That's a good idea, thanks!!!

SlowDragon profile image

Post from 3 months ago


Did you get full testing of thyroid and vitamins

Palpitations can be due to being under medicated or low vitamin levels

Biloxi profile image
Biloxi in reply to SlowDragon

She did T3 and T4 and those are normal every time I get tested. I haven't gotten vitamins since my annual physical last June, and they were normal then.

SlowDragon profile image
SlowDragonAdministrator in reply to Biloxi

What’s the actual results and ranges on vitamins?

Biloxi profile image
Biloxi in reply to SlowDragon

Well, this is what I found for vitamins: May 2019

B-12 349 (232-1245)

D 36.6 (30-100)

Thyroid tests: January 2020

(Last test on 112mcg after this I went back to 100 mcg)

TSH .1 (.34-5.6)

T4 FREE 1.17 (.6-1.6)

T3 FREE 3.05 (2.5-3.9)

I thought I had more info, but this is what I found...

SlowDragon profile image
SlowDragonAdministrator in reply to Biloxi

So B12 is low ...often anything under 500 can cause symptoms

Folate...very rarely tested in USA

Vitamin D is pretty good

Do you supplement?

36.6 ng/ml is 91nmol.


No ferritin or iron tests?

SlowDragon you said the Vitamin D looked pretty good. But not compared to it's own ranges. It's right towards the bottom surely?

SlowDragon profile image
SlowDragonAdministrator in reply to FancyPants54

This is USA units ...ng/ml

36.6 nag/ml is 91nmol

But it was still at the bottom of the reference range?

SlowDragon profile image
SlowDragonAdministrator in reply to Biloxi

Ft4 is 57% through range

Ft3 is 39.5% through range

So you likely need dose increase in levothyroxine

Most people on levothyroxine would find both of these are too low

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


SlowDragon profile image
SlowDragonAdministrator in reply to Biloxi

Low iron and or low magnesium can all cause palpitations

Are you supplementing vitamin D...we often need magnesium too






Iron deficiency


What’s your diet like?



Whole food?

Do you have Hashimoto’s?

SlowDragon profile image
SlowDragonAdministrator in reply to Biloxi

Normal means nothing...you need to know exactly where within range

Eg Ft4, if range is 12 - 22 ......on levothyroxine we need Ft4 at least over 60-70% through range, some need Ft4 even higher

Ft3 at least over 50% through range

Helpful calculator for working out percentage through range


Biloxi profile image
Biloxi in reply to SlowDragon

Thank you for your help and all this information! I'll look into supplementing vitamins. I used to take a multi vitamin, but stopped because I didn't think it was doing anything. Well, maybe it was! I'll be in contact with my doc tomorrow about this.

SlowDragon profile image
SlowDragonAdministrator in reply to Biloxi

Don’t take a multivitamin

Test and supplement as required

SlowDragon profile image
SlowDragonAdministrator in reply to Biloxi

Read Greygoose last reply on Multivitamins here


Improving nutrients improves conversion


SlowDragon profile image

Looking at previous posts you have Lupus ...so hypothyroid will be Hashimoto’s (autoimmune)


Do you have Lupus, Rheumatoid Arthritis, Hashimoto’s, Multiple Sclerosis, or any other autoimmune disease? If so, I can say without a doubt that gluten sparked the flame of your disease, and continuing to eat it is simply adding fuel to the fire.

Hashimoto's frequently 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 intolerance. Second most common is lactose intolerance

According to Izabella Wentz the Thyroid Pharmacist approx 5% with Hashimoto's are coeliac, but over 80% find strictly gluten free diet reduces symptoms, sometimes significantly. Either due to 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

While still eating high gluten diet ask GP for coeliac blood test, or buy test online BEFORE trying strictly gluten free diet

Assuming test is negative you can immediately go on strictly gluten free diet

If coeliac test is positive you will need to remain on high gluten diet until endoscopy, with maximum 6 weeks wait, officially

Trying strictly gluten free diet for 3-6 months

If no noticeable improvement, reintroduce gluten and see if symptoms get worse






Masurati temperatura bazala cu un termometru digital dimineata cand va treziti fara sa va dati jos din pat .Daca aveti sub 37 grade inseamna ca hormonii tiroidieni sunt insuficienti si trebuie marita doza, daca aveti 37 grade e bine ,daca e peste trebuie redusa doza pana cand obtineti o temperatura de 37 grade.Sper sa fie de foloc!

Hi I take 75g one day and 50g the next seems to work fine without any palpitations...

So I take 3 one day 2 the next been doing this for 2 months..

Hi I takes 75mg a day but rheumatologist felt I need to increase but 100 was too much so I now take 75 one day and 100 the next

My doctor increased my bisoprolol to slow my heart down. I am on 150mcg of levothyrooxin but also have permanent AF

If you are a woman over the age of 35-40, you need to consider that palpitations can also be caused, regularly, by perimenopause an then menopause itself. You may need some oestrogen supplementation to stop them, although your thyroid TSH result would indicate a dose increase might help. Use a pill cutter and cut your tablets up so that you can give yourself a small daily increase. I know a lot take their thyroxine alternating dose with day, but my body doesn't like that and needs me to take the same dose every day.

You asked if it matters if you take it at 6am or 7am. I don't think so. I vary mine by several hours on a regular basis and never notice it. If I wake for the loo in the early hours I take it then so I can have a drink as soon as I get up. Sometimes I won't wake until late. It varies in the "hours" category for me, not just half an hour.

I am trying to balance my levothyroxine and increase from 100 to 125. I am having a difficult time, and I think it's just trial and error. If you are sensitive to drugs you may have to go up and down a very small amount. I went up to 112 every day and started to get palpitations, anxiety and felt very 'speedy' and a bit out of breath. I then went 112 to 100 every other day, and that is slightly too much too. I now take 106 (like a crumb!) every other day and am working up to 112, which I think will be about right. No one can tell you how to do this, it is a very individual thing, and sometimes I cut down to 80mg if it goes too 'high'. However, increasing my dose has halved my fibromyalgia pain, and my gastro and fatigue symptoms are gone. Some people even do 100 mg for 5 days then 125 on the 6th. Try a few different things, and good luck.

Hi, i have the same problem, . I also get a lot of twitching, headaches and nausea. Twice i have seen a neurologist who has told me to reduce doseage myself when i have symptoms as the thyroid is very sensitive and changes.

My Gp however, did not agree and said i should stay on the same dose. 🤔 I find just taking half a tablet less helps a lot of the time.

But it would be nice to have a definitive answer.

It seems you’re seeking a response based on maths. I haven’t the attention span to read all of these responses, but here’s the computation.

1 Assuming the half life of LT4 is nine days, over a period of nine days taking 100 mcg, you’ve consumed 900 mcg.

2 Your instinct and very good reasoning says you need 88 per day. Over a period of nine days, you want to consume 792 mcg. Rounding up, that’s 800 mcg.

Assuming you have 100 mcg tablets, you want to spread 800 out over nine days. Here’s a pictorial representation:

100. 100 50 100. 100. 50 100 100 50

Every third day take half a tablet. A little bit gets lost in splitting tablets so it’s probably quite close to 792 in nine days 🙃

Good luck!

Biloxi profile image
Biloxi in reply to RockyPath

Thank you! I'd heard of people doing something like this, but just didn't know how to change it up. I do have 100mcg tablets, so simply cutting in half and trying this method out is easily doable.

Hi. I alternate dosages. I take 112 for 4 days and 125 for 3. I find 112 is not quite enough but staying on 125 gives me palpitations especially after eating. I’ve had a complete thyroidectomy.

I spread it out through the week. So basically my dosage is 112 but Sunday Tuesday and Friday I take 125. Seems to work for me.

You all have given such helpful advice, and have given me alot of ideas. I'll definately be trying out these methods of alternating/ splitting doses. I really appreciate all of you! Hope everyone has a great day and stay healthy 💖

I am so sorry your not feeling well . Palpitations can really make one very uncomfortable and somewhat concerned. From my own experience I can tell you that it's very important to know your FT-3, FT4, TSH, Iron/ferritin levels . They are very telling . Low Iron levels can cause palpitations and anxiety .In addition I found that Celtic Sea Salt helped/helps with adrenal /electrolytes and may cause palpitations too if low.

If you found that 100mcg T4 was to high for you and causes you palpitations and 88mcg dose too low you might want to try alternating between the two doses . You might just do well with an in-between dose that way.

It might be possible that you don't convert well your T4 to T3 well and your a bit low on your T3 . The heart has T3 receptor sights and if it's not getting enough it can cause palpitations.

It's very important that we know as thyroid patients our lab results to be able to see what needs to be tweaked for our more *Optimal* thyroid levels.

Meantime you might want to add some Magnesium , fish oil, to help you with the palpitations.

Wishing you Fast Resolutions and *Optimal* Being.

Testing is probably your only answer

So many possibilities,T4 itself doesn't do much it's how, when,and if its converted into T3.(liver and digestive function).palpitations might not be connected to thyroid sometimes,could be electrolytes

Hiya. I have been having a lot of heart palpitations. I had them for several hours a day but they seemed to have calmed down now. I talked to my doctor about upping my dose of levothyroxine even though I was in the 'normal' range and I now take 75 one day and 100 the next.

You may also like...