Under active thyroid : Hi, I was diagnosed with... - Thyroid UK

Thyroid UK

119,354 members138,649 posts

Under active thyroid

MartinHayes67 profile image

Hi, I was diagnosed with under active thyroid 9years ago, am taking 175 levothyroxine, which seemed to sort it, but have been feeling tired, with no energy lately. Had a bloody check with Medicare , results below, any suggestions

12 Replies

Yes that’s the dose I’ve always been on, I am a builder and work is very physical so the tiredness is a big problem

SlowDragon profile image

Have you had change in brand of Levothyroxine recently?

Many people find different brands are not interchangeable

Your results show you are very under medicated

Also need vitamin D, folate, ferritin and B12 tested as these are often low when hypothyroid

Ask GP to test vitamins

You will need 25mcg dose increase in Levothyroxine and bloods retested 6-8 weeks later

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).

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.

Being male and very active job, you may need higher dose than average

Also what foods to avoid (note recommended to avoid calcium rich foods at least four hours away from Levo)


Always take Levo on empty stomach and then nothing apart from water for at least an hour after.

Many take Levothyroxine early morning, on waking, but it may be more convenient and possibly more effective taken at bedtime.


Other medication at least 2 hours away, some like iron, calcium, vitamin D or magnesium at least four hours away from Levothyroxine

Many people find Levothyroxine brands are not interchangeable.

Once you find a brand that suits you, best to make sure to only get that one at each prescription. Watch out for brand change when dose is increased or at repeat prescription.

Many patients do NOT get on well with Teva brand of Levothyroxine. Though it is the only one for lactose intolerant patients

Hi, thank-you for reply, I did bloody test early morning and was 24 hrs clear of previous tablets. I have had change in brand from the chemist, will keep an eye on that and have made doctors appointment. Thanks

shaws profile image
shawsAdministrator in reply to MartinHayes67

As you do very physical work I would assume you use up your T3 more quickly. You are obviously on too low a dose of levothyroxine as your TSH is much more than 1 - which is the aim (or lower) once we're diagnosed. Unfortunately doctors don't seem to know too much except to think that if results are somewhere in the ranges (i.e. they've been directed not to prescribe until TSH is 10 ) whilst in other countries it would be around 3, so if in the UK we're not diagnosed until TSH is 10, a TSH of 14 may appear o.k. to GP.

The aim of taking thyroid hormones is to relieve ALL of our clinical symptoms - again in these 'modern' times doctors appear to know none at all. Before blood tests we were diagnosed upon our clinical symptoms alone and prescribed NDT (natural dessicated thyroid hormones that contain all the hormones a healthy thyroid gland would do).

Levothyroxine is an inactive hormone also known as T4 and should convert to sufficient T3(that doesn't always happen and they rarely check FT3). T3 is the Active Thyroid Hormone and our heart and brain have the most T3 receptor cells and our body has millions. We need to be a good converter of levo into lio (liothyronine - T3).

Several research teams have proven that a combinationT4/T3 suits many and on a 3:1 or 4:1 basis.

I am not medically qualified but had to diagnose myself with hypo. I now source my own thyroid hormones.


The following may be helpful. It was by one of Thyroiduk's Advisers (deceased) who only took one blood test for the initial diagnosis and thereafter it was all about small increments until symptoms went. He'd never prescribe levo - only NDT or T3 (T3 for thyroid hormone resistant patients).


Your FT4 is at the bottom of the range when it should be nearer the top. FT3 could also be higher.

MartinHayes67 profile image
MartinHayes67 in reply to shaws

Thank you, will have a good read, another problem is that I can’t loose weight, real watch my diet, eat plenty of fruit, but struggle, on the go all day with physical job, trying swimming 2 miles a week , and walk the dog every day, only got to look at a cake and put weight on 😡

in reply to MartinHayes67

Cut down on the exercise until hormone replacement has increased and you feel better. You are using up all you active thyroid hormones and not able to replace. Also avoid dieting as this lowers active thyroid hormones. You might also want to ask your doctor to test folate, B12, vitamin D and ferritin as these need to be at a good level for you to benefit from thyroid hormones. Keep us updated with how you get on. It can take a while to get well with a few hurdles on the way sometimes. First off you need an increase of levo.

shaws profile image
shawsAdministrator in reply to MartinHayes67

When we're hypo, and due to our metabolism being lowered (hypo) we can gain weight even if we eat the same as before being diagnosed. Levothyroxine can cause weight gain because the dose may not be optimum and doesn't increase our metabolism. I know the following is mainly of women but men too can gain weight if not on an optimum dose or levo isn't working as it's supposed to do.


Exercising etc before we're on an optimum dose, lowers our hormone levels and weight increases.

Hey there MartinHayes67

Yes, ditto what has already been said. If vitamins and minerals aren't optimal thyroid hormone replacement will not be as effective - so we also need to know your ferritin, folate, and vitamins D and B12. along with their relevant ranges.

SlowDragon profile image
SlowDragonAdministrator in reply to MartinHayes67

Because you are under medicated, weight loss will be virtually impossible

TSH needs to be well under 1 for many

Most important results are FT3 and FT4

Getting vitamins tested and optimal by supplementing likely essential too

SlowDragon profile image
SlowDragonAdministrator in reply to MartinHayes67

If new brand was Teva, this upsets thousands of people

Just checked my 50 and 25 tablets are Teva

SlowDragon profile image
SlowDragonAdministrator in reply to MartinHayes67

So this could be the problem

What's your 100mcg brand?

See GP, or ring to request new prescription. Explain what's happened, give copy of test results to GP to add to your record....make sure to get note added to ALL future prescriptions "NO TEVA"

Bloods should be retested 6-8 weeks after ANY change in brand of Levothyroxine

Also put in yellow card for Teva


You will still need to ALWAYS check bag BEFORE leaving pharmacy......a note saying No Teva doesn't necessarily mean they won't still give it you ..unless you kick up a fuss and refuse it before leaving the building

Many people have to ring around several pharmacies to find brand they need

You may also like...