How do you know where your meant to be with you... - Thyroid UK

Thyroid UK

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How do you know where your meant to be with your levels?


Struggling to find out if I’m better with my T4 at 15 (10-25) or 25 can’t say there’s much difference where ever I am. Still having tiredness, short tempered, cold symptoms, dizzy. Gp just done bloods and every thing normal 🙄🙄🙄

12 Replies

Please get a print-out of your results from the surgery and do you do the following when getting a blood test:-

The earliest blood draw.

Fasting (you can drink water).

Allow a gap of 24 hours between last dose of levothyroxine and the test?

NHS don't usually do a Full Thyroid Function Test but it is more informative. A FTF test is:-

TSH, T4, T3, Free T4, Free T3 and thyroid antibodies.

You can get a home private blood test and quite a number of our members have done so. I shall give a link just in case you'd want to do this.

You should also ask GP to test B12, Vit D, iron, ferritin and folate. Everything has to be optimal.

The aim is a TSH of 1 or lower (GP should increase dose until this is achieved - except they seem unaware of this fact and assume 'somewhere' in range is fine. No it isn't.

I'm not medically qualified but had to diagnose myself as hypo thanks to TUK.

Carrie97 in reply to shaws

My T4 was 19 10-25 tsh 0.69 0.30-3.30.

shawsAdministrator in reply to Carrie97

Before the introduction of levothyroxine along with the blood tests, we were all diagnosed upon our clinical symptoms and given a trial of NDT (natural dessicated thyroid hormones - now removed through False Statements made about it - even though it was used since 1892 and is still today (usually by sourcing it oneself or getting a professional to prescribe).

The TSH result may cause the GP to adjust your dose, due to the low TSH. Most think that would mean you've gone hyPERthyroid. Clinical symptoms are more important than results as it is symptoms that cause us problems. Also more informative are the Free T4 and Free T3 and I'll give a link for information. We can be poor converters of T4 into T3. T4 is inactive and it has to convert to T3. T3 is the Active Thyroid Hormone needed in our millions of T3 receptor cells.

I didn't feel well at all on levothyroxine and I was diagnosed when TSH was 100. I improved when I was given a T4/T3 combination and then went onto T3 alone. If you're in the UK they no longer prescribe T3 due to cost (or the excellent excuse of cost).

You need a Full Thyroid Function Test which is:-

TSH, T4, T3, Free T4, Free T3 and thyroid antibodies.

All blood tests for thyroid hormones have to be at the earliest possible, fasting (you can drink water) and allow a gap of 24hours between last dose of levo and the test and take afterwards. This helps TSH to be at its highest and prevents doctor reducing dose.

Thyroid hormones are usually taken when we get up with one full glass of water and wait an hour before eating. Some prefer a bedtime dose, therefore stomach will have to be empty and it takes about 3 hours after meal before you take the tablet. Miss night dose if having a blood test next a.m. and take after test and night dose as usual.

It's not really about the FT4, anymore than it is the TSH. The important number is the FT3, and that depends on how well you convert. Your FT4 could be right up at 25, but your FT3 could be right down at the bottom of the range if you're not converting well. And, if you don't feel good with your FT4 at 25, then that's probably the case. :)

Carrie97 in reply to greygoose

I’ve had my T3 tested and there didn’t seem to be any conversion issues

greygoose in reply to Carrie97

So, what were the results of your FT3 and the FT4 tested at the same time? Why do you say there didn't seem to be any conversion issues?

Carrie97 in reply to greygoose

This was years ago and T4 was 16 and T3 4.8 (3.0-7.0) so both mid range at the time

greygoose in reply to Carrie97

Well, a lot could have changed in 'years'.

Carrie97, The result you quote shows being quite undermedicated. Most people will feel best with their freeT3 in the top third, and yours is below halfway.

If this is the argument that was made to you about those results, then it sounds very very convoluted to me:

1) FreeT4 and freeT3 were at similar points in the range and THEREFORE your conversion was good.

2) AND THEREFORE conversion will still be good at the higher dose most people need.

3) AND THEREFORE your conversion will still be optimal today.

There are a lot of logical leaps in that argument. I don't see any reason to believe that having okay conversion while on a low dose suggests your conversion will still be good once you start getting your dose to reasonable levels, so the argument falls down immediately. The only way to spot poor conversion in a blood test is to get freeT4 high in range and then see if freeT3 matches.

It's also very common to do fine on Levothyroxine for years and then at some point become unwell and need T3. I've seen at least one example where this was because conversion became atrocious.

It's simpler just to get the blood tests and make sure. If your doctor won't do you a full thyroid panel then go for the mailorder finger prick blood tests.

Also very important to look into vitamins. All these things need to be optimal for thyroid hormone to work properly, and being hypothyroid trashes vitamin levels.

Carna in reply to SilverAvocado

I was well on Levo for many years. Became unwell about 20 years in and switched to NDT and was so much better until my brand changed and I crashed. GP panicked as my TSH was very low and said I had to go back onto Levo. I was better initially but only because I was so bad when I went on it. GP refused to look at any other treatment. Finally saw a private endo who is prescribing me T3 as part of T4/T3 combination therapy and, at last, I am beginning to improve. My TSH remains at what my GP would class as too low and would want to reduce my medication.

I cannot thank the people on here enough for their help, wisdom and support and encouragement to go forward and get well again.


FT4 is 33% in range. Looking for FT4 to be at least in top 66% of range

6 months ago you posted these results

Extremely low FT3 - only 16% through range

Needs to be at least 50%

You have Hashimoto's

Low vitamin D, folate, ferritin and B12 are EXTREMELY common

When were these vitamins last tested and what supplements do you currently take?

Good vitamin levels help improve conversion rate

Hashimoto's 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

IBS and diarrhoea suggest coeliac or gluten intolerance

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

Thanks for your help. My dose is 200mcg isn’t that a lot? I’m 5ft 3 and have had hashi for 12 years

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