Levothyroxine side effects : I’ve recently been... - Thyroid UK

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Levothyroxine side effects

Coriander000 profile image

I’ve recently been prescribed Levothyroxine for under active thyroid and I’m experiencing over heating. I’m constantly too hot ( my norm is always cold) - could this be a side-effect of the medication?

16 Replies

Just a personal thing, I started using this useless thing in Apr 2014 with 25mcg and increased dosage as prescribed by useless GPs to 75mcg until Dec 2016. In December one day I decided that it is of no use, my heavy head feeling is not going anywhere. I stopped it in Dec 2016. Yesterday did my periodic TSH test and result is 2.627. Levo is just a marketing stunt with those corrupt and incompetent GPs involved.

SlowDragon profile image
SlowDragonAdministrator in reply to BB0IAIHE

Just because you seem to manage without Levothyroxine, doesn't mean others can.

Perhaps you had temporary thyroiditis

BB0IAIHE profile image
BB0IAIHE in reply to SlowDragon

yes could be, but I am better off them than using that useless medicine. GPs dont believe in temporary thyroiditis,Every time I went to a GP and then only answer was "Levo is life long, you cant stop taking it". When I was on Levo my reading was always between 5-7. After 2 years of stopping it see the TSH now. I believe real research by honest people is required. All the GPs I met were useless.

BB0IAIHE profile image
BB0IAIHE in reply to BB0IAIHE

I believe instead of looking for synthetic thyroid medicine, we should concentrate on vitamins, minerals etc which supports functioning of the thyroid gland. Levo is synthetic.

MissGrace profile image
MissGrace in reply to BB0IAIHE

I’m glad you are well and this worked for you.

Such advice could be deadly for some people on here who produce none of their own thyroxine, have had their thyroid removed etc. You can take as many vitamins and minerals to support the functioning of the thyroid gland as you like - but if it is being destroyed by hashimotos and has shrivelled to a useless lump or been removed by surgery, it won’t make you well!

There are many reasons for being hypo, some do reverse and are blips, some don’t and require lifelong thyroxine replacement in some form or other. 🤸🏿‍♀️🥛

NWA6 profile image
NWA6 in reply to BB0IAIHE

That’s brilliant BB0IAIHE! I’m so pleased for you that you have found an answer that works for you. You must have a lot of knowledge about vitamins and minerals ect. I think it’s fascinating that you’ve taken this route and you feel active and well. Did you have Autoimmune? Did/do you have a full thyroid testing?

It’s not a route that I would choose, I’d been very unwell but I do think that diet and supplements play a huge part in thyroid health and to support the synthetic hormones I have to take. In fact I was quite anti supplements for most of my life. I’d have scoffed at people taking daily vitamins ect I felt that people should have better diets. But now that I’m older and the way our food is farmed/manufactured I know that that’s not the case anymore and my condition means I’m not as adept at taking in those vitamibs and minerals. It’s a minefield to try and research and be one more knowledgable.

Hay2016 profile image
Hay2016 in reply to BB0IAIHE

Unfortunately no amount of vitamins will help some of us with no thyroid as we depend on hormone substitutes be it synthetic or not.

Glad you found a solution.

BB0IAIHE profile image
BB0IAIHE in reply to Hay2016

Well my point was just to create a perspective. I did rely on synthetic thyroxine for 2 years. I believe there is more to this problem of hypothyroidism than just thyroid gland secreting the hormones properly. I didnt find a solution thru vitamin supplementation , I still have that heavy head. Studying the supplement side of thyroid function may actually be a solution for many.

greygoose profile image
greygoose in reply to BB0IAIHE

Creating a perspective doesn't normally involve slamming a product and calling it useless. It may not have helped you, but that doesn't make it useless for everyone. There could be a lot of reasons why it didn't help you, how many have you investigated? For a start, maybe you just never took enough of it. And, if you were just going by your TSH, then you don't have the full picture. So, all told, your perspective seems to be full of holes, doesn't it. :)

MaisieGray profile image
MaisieGray in reply to BB0IAIHE

Writing "Levo is just a marketing stunt with those corrupt and incompetent GPs involved" is not offering a perspective, but is a rather ridiculous assertion. What marketing stunt is it exactly? Levothyroxine is as cheap as drugs come, in fact the NHS reimburses pharmacists as little as £1.55 for 28 tablets of 25 mcg T4, so exactly what corruption are the GPs involved in, relating to the prescribing of Levo?

SlowDragon profile image

Yes this could be cause

Standard starter dose is 50mcg Levothyroxine? Is this how much you were prescribed?

Do you have blood test results and ranges from before starting on Levothyroxine?

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested.

Also important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if Thyroid antibodies are raised

Different brands of Levothyroxine can cause different side effects often due to fillers in tablets. Teva brand upsets many people.

I realise I have a lot to-learn as I’m a newbie - thank you for responding.

SlowDragon profile image
SlowDragonAdministrator in reply to Coriander000

Bloods should be retested 6-8 weeks after each dose increase

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also extremely important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if Thyroid antibodies are raised

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and fasting. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Last Levothyroxine dose should be 24 hours prior to test, (taking delayed dose immediately after blood draw).

Ask GP to test vitamins and antibodies if not been done

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or all vitamins


Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

Medichecks currently have an offer on until end of May - 20% off


If antibodies are high this is Hashimoto's, (also known by medics here in UK more commonly as autoimmune thyroid disease).

About 90% of all hypothyroidism in Uk is due to Hashimoto's.

Low vitamins are especially common with Hashimoto's. Food intolerances are very common too, especially gluten. So it's important to get TPO and TG thyroid antibodies tested at least once .

Link about thyroid blood tests


Link about antibodies and Hashimoto's



List of hypothyroid symptoms


The aim of Levothyroxine is to increase the dose slowly in 25mcg steps upwards until TSH is under 2 (many need TSH under one) and FT4 in top third of range and FT3 at least half way in range

All four vitamins need to be regularly tested and frequently need supplementing to maintain optimal levels

NHS guidelines on Levothyroxine including that most patients need somewhere between 100mcg and 200mcg Levothyroxine. Also what foods to avoid (note recommended to avoid calcium rich foods at least four hours away from Levo)


NICE guidelines


The initial recommended dose is:

For most people: 50–100 micrograms once daily, preferably taken at least 30 minutes before breakfast, caffeine-containing liquids (such as coffee or tea), or other drugs.

This should be adjusted in increments of 25–50 micrograms every 3–4 weeks according to response. The usual maintenance dose is 100–200 micrograms once daily.

Levothyroxine does seem to speed up our system ,which when you can hardly get up the stairs is something you want.In doing so it could be causing you to heat up. In my case it exposed angina when I was going up a very steep hill.The doc said I had irregular veins!

hello. I was hunting the web about this. I.m on 25mg Levothyroxin and have been for 4 months. Mostly in lockdown. So have never had a blood test since.

Im so hot and clammy most of the time. Not pouring with sweat but like a film. My hands really hot. They used to be cold or even pins and needles.

I sleep with no blanket or pj.

Feel like Ive been run over by a truck in the morning. So tired and head fussy. Plus drink loads in the evening.

Advice please. X

Lora7again profile image
Lora7again in reply to Hotandhot

25mcg is a very low dose and you might need an increase. When I took Levothyroxine I felt worse before I felt better because your pituitary gland senses there is thyroxine in your system and stops stimulating your thyroid gland. Once I got to 100mcg I started to improve and then I increased it to 125mcg. When I was on no treatment and had very low T4 and T3 I would have night sweats and I would have to get up and change the bed and my night clothes.

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