Under active thyroid and levothyroxine - Thyroid UK

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Under active thyroid and levothyroxine

Mjpp84 profile image

Hi all, I have been diagnosed with an under active thyroid for a couple years. I am a 34 yr old male, currently taking 125-150mg levothyroxine, alternating 125/150 weekly. Symptoms lately have been pretty bad - tiredness, fatigue, muscle aches and pains, slowness of thought. Most recent TSH test was 1.3 well into normal range. Any help and advice would be greatly appreciated, many thanks

12 Replies

Your TSH may now be well into range, but that means it's reached the point where it doesn't tell you very much about your thyroid status. Your thyroid hormones could still be low, even though the TSH isn't too bad. You absolutely need your FT4 and FT3 tested to know where you are.

Do you really mean that you take 125 mcg levo one week, and 150 mcg the next? I've never heard of that before, and can't really see the point. You might just as well alternate days, it would add up to the same thing, and might be gentler on your system. And, I would think you probably need 150 mcg every day. Your TSH could easily be a bit lower without panicking your GP. I, for one, wouldn't want my TSH that high.

Have you had your vit D, vit B12, folate and ferritin tested? How about antibodies?

SlowDragon profile image

Welcome to the forum

Just testing TSH is completely inadequate

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 you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies

Do you know if you have had thyroid antibodies tested?

Ask GP to test vitamin levels (and thyroid antibodies if not been tested)

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

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

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Is this how you do your tests?

What vitamin supplements are you currently taking?

If any

Private tests are available as NHS currently rarely tests Ft3 or thyroid antibodies or all relevant vitamins

List of private testing options


Medichecks Thyroid plus ultra vitamin


Medichecks often have special offers, if order on Thursdays

Thriva Thyroid plus vitamins


Blue Horizon Thyroid Premium Gold includes vitamins


If TPO or TG thyroid antibodies are high this is usually due to Hashimoto’s (commonly known in UK as autoimmune thyroid disease).

About 90% of all primary hypothyroidism in Uk is due to Hashimoto’s. Low vitamin levels are particularly common with Hashimoto’s. Gluten intolerance is often a hidden issue to.

Link about thyroid blood tests


Link about Hashimoto’s


List of hypothyroid symptoms


Getting vitamin levels optimal often improves symptoms

Essential to always test Ft4 and Ft3

Mjpp84 profile image
Mjpp84 in reply to SlowDragon

Thanks for the tips, there is a lot of good detail and information here, although sometimes the science is overwhelming. When I first got diagnosed 2 yrs ago TSH was at 19. August last year TSH was 1.7, FT4 26.3 and FT3 4.9. Testosterone normal at 24.1 nmols/L, iron profile normal, ferritin normal at 114, ESR normal at 2, short synacthen test done September last year normal baseline cortisol 311 30 min cortisol 462. Other tests e.g. B vitamin normal from what can remember, the above tests were done through an endocrinologist. I’m not currently taking any supplements or vitamins. Do you have any further thoughts ? The symptoms at the moment are difficult to deal with.

SlowDragon profile image
SlowDragonAdministrator in reply to Mjpp84

So tests from August last year are now old and out of date

But can you add the ranges on Ft4 and Ft3 results

Strongly recommend getting FULL thyroid and vitamin testing Either via GP or privately

ALWAYS get bloods tested as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test

Is that how you did last test?

Have you had thyroid antibodies tested?

Essential to test vitamin D

Add actual results and ranges on B12 and folate if you have them

What’s your diet like?

Vegetarian or vegan?

Mjpp84 profile image
Mjpp84 in reply to SlowDragon

These are the results I have noted although I will request other details from my GP. I’m thinking of going down the private testing route. I haven’t been so strict on blood test timings from what can remember. I take thyroxine on waking roughly 6-6.30 every morning with water and leave it c. 45 mins to an hr plus before caffeine or breakfast. In terms of caffeine, I have c. 2 coffees and 2 teas a day, and generally drink good amounts of water. Diet is pretty normal and includes dairy, wheat, meat and moderate alcohol with quite a lot of fruit and veg. Have wondered about the effect of making diet changes but not sure where to start. Symptoms are worsened the next day following any moderate exercise or activity. I try and keep myself fit when I can but this is challenging (c. 6ft, 11st, healthy BMI). Do you have any thoughts on diet ?

Mjpp84 profile image
Mjpp84 in reply to Mjpp84

Or taking additional supplements or vitamins ?

SlowDragon profile image
SlowDragonAdministrator in reply to Mjpp84

Well if cause of your hypothyroidism is autoimmune thyroid disease (Hashimoto’s) then hidden food intolerances are extremely common

(Over 80% Hashimoto’s patients find strictly gluten free diet helps or is essential. About 60-70% lactose can be an issue)

That’s why it’s so important to get thyroid antibodies tested

If antibodies are both negative then an ultrasound scan of thyroid can be helpful

Vitamins...test first ...then only supplement what’s needed

Mjpp84 profile image
Mjpp84 in reply to SlowDragon

It sounds like I might need to get some more tests done although I have had quite a few regular tests done and don’t seem to be near an answer for the moment or near to a cure. I’m tempted to go gluten and dairy free to see if this has an impact.

SlowDragon profile image
SlowDragonAdministrator in reply to Mjpp84

Really want to Test antibodies first

And definitely get coeliac blood test before trying strictly gluten free diet

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. Dairy is second most common.

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

While still eating high gluten diet ask GP for coeliac blood test first or buy test online for under £20, just to rule it out first

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

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

Trying gluten free diet for 3-6 months. If no noticeable improvement then reintroduce gluten and see if symptoms get worse






Non Coeliac Gluten sensitivity (NCGS) and autoimmune disease


The predominance of Hashimoto thyroiditis represents an interesting finding, since it has been indirectly confirmed by an Italian study, showing that autoimmune thyroid disease is a risk factor for the evolution towards NCGS in a group of patients with minimal duodenal inflammation. On these bases, an autoimmune stigma in NCGS is strongly supported


In summary, whereas it is not yet clear whether a gluten free diet can prevent autoimmune diseases, it is worth mentioning that HT patients with or without CD benefit from a diet low in gluten as far as the progression and the potential disease complications are concerned

SlowDragon profile image
SlowDragonAdministrator in reply to Mjpp84

Without ranges on Ft4 and Ft3 it’s impossible to say wether they are good or bad

Ft3 looks like might be on low Side

Mjpp84 profile image
Mjpp84 in reply to SlowDragon

If FT3 is low what would the remedy look like ?

SlowDragon profile image
SlowDragonAdministrator in reply to Mjpp84

Getting vitamin levels optimal often improves conversion of Ft4 to Ft3

Did you take levothyroxine before this test?

Or was last dose 24 hours before

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