What are Optimal levels for someone on T3 and T... - Thyroid UK

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What are Optimal levels for someone on T3 and T4 combination?

AlphaInsanity1 profile image

Hello - I have just had my results back from Medichecks. I am on 75mg of Levothyroxine and 5mcg of Liothyronine.

TSH 0.13 mlU/L (range:0.27 - 4.2)

Free T3 5.0 pmol/L (range: 3.1 - 6.8)

Free Thyroxine 16.1 pmol/L (range: 12 - 22)

I feel okay - but my memory/brain fog is horrendous and I still have thinning hair. Would these results be classified as 'optimal' levels?

I have been taking extra B12 and Vitamin D for 3 months now and they are back up to 'normal'

Vitamin B12 - 84pmol/L (range: 25.1 - 165)

Vitamin D - 180 mol/L (range: 50 - 200)

Folate 12.2ug/L

So I am not sure why I still don't feel myself? Or whether that is it now and I should take this as a win?

11 Replies

Optimal is a feeling, not a number. If you don't feel optimal, then you aren't. Blood tests are just a rough guide, not the be-all-and-end-all of thyroid treatment.

Having said that, what your labs are telling us is that your FT3 is still a bit low - plenty of room for an increase in T3. You may also need an increase in levo - some people do, some don't - but think about that at a later date. For now, concentrate on getting the FT3 a bit higher. :)

Thank you!

You're welcome. :)

SeasideSusie profile image


I agree with Greygoose, FT3 might be better higher, often on combination hormone replacement TSH is low or suppressed, FT3 in the upper part of it's range and FT4 wherever you need it.

I think you can reduce your Vit D supplement now to a maintenance dose, the recommended level is 100-150nmol/L so the top end of that range would be good.

I'd aim for a higher Active B12, as a level below 70 is suggestive of testing for B12 deficiency, a level over 100 would seem a good place to aim for.

Folate might be low, do you have a range, one range goes up to 60, another up to about 20 and another up to about 15. If your range just says >xx then well into double figures is considered about right, if there's a proper range then it's recommended to be at least half way through it.

SeasideSusie, can I ask why TSH is suppressed on T4/T3 combo meds? Want to get it straight in my own head as have an endo appointment on Thursday so need to be prepared!

Sorry to jump on someone else's thread, I did ask a question on Friday but sadly didn't get too many replies.

SeasideSusie profile image
SeasideSusieAdministrator in reply to Fluffysheep

T3 tends to lower or suppress TSH, it's what it does, sorry I don't know the science behind it.

No problem, and thank you for replying!

I think the folate range was from 2.9 - 14.5

I shall continue with the B12 supplements and reduce my Vit D supplement to a maintenance dose as you have suggested.

I shall now suggest upping my T3 as you have both suggested to my Doctor.....wish me luck! Thank you for the advice. It is always appreciated!


Your labs are good. FT3 is only half way through range & some need theirs higher. I don’t but I knew when optimal was reached because brain fog cleared.

Others have mentioned your folate but what about iron? Meds need adequate iron to work properly. Do you have a ferritin result to post?

Also another post has just reminded me of the importance of adequate carbs as assimilation of meds (conversion/utilisation) can only happen with adequate, balanced & useable insulin/glucose levels. Adrenals issues caused by low thyroid hormone can prevent this from happening but a good diet & adequate replacement meds will help improve med utilisation.

This is one of the major reasons why symptoms often lag behind good biochemistry. This need not be your win if you keep addressing possible issues that are preventing meds from giving you whole well-being, and it might just be time that you need.

SlowDragon profile image

Was this test done as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test

Last 2.5mcg T3 roughly 8-12 hours before test

Assuming yes....your results show you have room to increase T3

Look at adding 2nd 5mcg dose T3 roughly 12 hours after morning dose

No ferritin result?

Are you on strictly gluten free diet

Do you always get same brand levothyroxine at each prescription

Which brand?

Rather than just taking B12

supplementing a good quality daily vitamin B complex, one with folate in (not folic acid) may be beneficial.

This can help keep all B vitamins in balance and will help improve B12 levels too

Difference between folate and folic acid


B vitamins best taken after breakfast

Igennus Super B is good quality and cheap vitamin B complex. Contains folate. Full dose is two tablets per day. Many/most people may only need one tablet per day. Certainly only start on one per day (or even half tablet per day for first couple of weeks)

Or Thorne Basic B is another option that contain folate, but is large capsule

IMPORTANT......If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 7 days before ALL BLOOD TESTS , as biotin can falsely affect test results



SlowDragon profile image

Looking at previous post your hypothyroidism is autoimmune thyroid disease also called Hashimoto’s

Presumably you have had thyroid antibodies tested?

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


20% of Hashimoto's patients never have raised antibodies


Paul Robson on atrophied thyroid - especially if no TPO antibodies


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 with Hashimoto’s 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


The obtained results suggest that the gluten-free diet may bring clinical benefits to women with autoimmune thyroid disease


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


Despite the fact that 5-10% of patients have Celiac disease, in my experience and in the experience of many other physicians, at least 80% + of patients with Hashimoto's who go gluten-free notice a reduction in their symptoms almost immediately.

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