Thyroid UK
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Taking T4 but is it time for T3

Taking T4 but is it time for T3

I have had problems over the last year with fluctuating thyroid hormones, a very difficult 6 months with what was eventually diagnosed as reactive arthritis following food poisoning but most recently just not feeling very well. I have made every attempt to ensure that B12, ferritin, Vit D are all in reference range but have attached my latest thyroid results.

I have Hashimotos and am prescribed 125 levothyroxine daily but suffered last week with eptopic beats, problems sleeping and generally get rubbish. I did the blue horizon test - decided against a visit to unsympathetic GP who would only test TSH - and on the basis of this result increase T4 which would tip me over the edge....

I don't think I am converting very well is it time to introduce T3? can this high level of T4 cause me problems - I feel weary but at the same time struggle to sleep, pounding heart, irritable and everything feels an effort.

Interpretations and thoughts welcome

12 Replies

Before you add T3 your doctor hasn't increased levothyroxine to bring your TSH to 1 or lower. He, it seems to me, has been happy to keep your TSH towards the top of the range when it should be the bottom.

Make another appointment and email and ask for a copy of Dr Toft's Pulse Online article. Highlight question 6 and tell your doctor you want an increase and that you want your TSH to be around 1 or lower. Point out what Dr Toft says. Some doctors pay no attention and if yours doesn't I'd source my own T4 or add some T3.

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Thanks, my result 3 months ago was TSH of 1.6... GP's were happy when my TSH was 5.3 despite taking medication because I was in reference range grrrrrrrr - I will get no joy and they will ignore these blue horizon results. Question is as my T4 level is already high would increase in dose just push up my T4 level and do little to improve T3?


I'm assuming you had a fasting blood test at the earliest possible and didn't take levo for about 24 hours before the blood test? That you also left approx 24 hours gap between your last dose of levo and the blood test?


Yes - last dose Sunday 6 a.m. BH blood test Monday at 9 a.m.


As you have Hashimoto's then you may find adopting 100% gluten free diet can really really help reduce symptoms, and lower antibodies too. Selenium supplements can help reduce antibodies and improve T4 to T3 too.

You do not need to have ANY obvious gut issues, to still have poor nutrient absorption or low stomach acid or gluten intolerance

Best advice is to read as much as you can. Vitamin and minerals levels are very important, but standard NHS thinking, doesn't at the moment seem to recognise this. You will see, time and time again on here lots of information and advice about importance of good levels of B12, folate, ferritin and vitamin D, low stomach acid, leaky gut and gluten connection to autoimmune Hashimoto's (& Grave's) too.

What are your vitamin D levels? Most of us need it around 100

Long research article - final conclusion paragraph below

"In conclusion, bedtime intake of levothyroxine in our study significantly improved thyroid hormone levels. This may be explained by better gastrointestinal bioavailability at night or by less uptake interference by food or medications. As shown in this study, bedtime administration is more convenient for many patients. Clinicians should inform their patients about the possibility of taking levothyroxine at bedtime. A prolonged period of bedtime levothyroxine therapy may be required for a change in QOL to occur."


You're right, it is time to add some T3 because you aren't converting very well at all. And adding more T4 might lower your TSH, but it is unlikely to raise your T3 very much. And if you have to too much unconverted T4 hanging around, you risk producing excess rT3.

Have you had your vit D, vit B12, folate and ferritin tested? Because these all need to be optimal before you start T3.


Totally agree with Greygoose.

This is what I'm currently experiencing. With all that unconverted T4 sloshing around I think you are getting the odd hyper symptom caused by a high level of T4 in your blood...ectopics, difficulty falling asleep. BUT.......

You are still experiencing hypo Dymptoms because your FT3 level is low.

I would suggest that it's time to lower your T4 and add some T3. You clearly have a conversion problem.

could you go and see an endo?

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Your free T4 looks extremely high!! I'm pretty sure that you are supposed to be in the middle of that range, and certainly not near the top of that range. Your free T3 looks like it could be increase. That hormone is supposed to be near the top of that range. Check out Might be good to stop synthetic thyroid t4 only medication and try Natural Dessicated Thyroid medication. Take care!


I agree that you're probably not converting to T3 properly. Have your reverse T3 checked. T4 can convert to it instead of T3. My TSH used to always be perfect, around 1.0, but my RT3, which doesn't really do anything, was astronomical due to stress. I went on a T3 only regimen, no T4, and felt great, and my RT3 went down to a low number over a year or so. Your doctor will freak out, because your TSH will be suppressed, mine's been around .01, but if your body has enough T3, it doesn't need T4 to convert, so TSH goes low. There is god info supporting this if you look (and for you to share with your ignorant GP).

Over time, I was put on combo T3/T4, but my doctor took me back off T4 and I'm just on T3 now. You might also try natural thyroid hormone - I can't, due to allergens.

Getting gluten and other food allergens out of your life is a good strategy, as well as reducing inflammation. Ensuring you have enough iodine and selenium is important, too.

If you go the T3 route, you'll want to start low, and likely take it in 2 doses a day as it has a shorter half life than T4. I started on 10 mcg a day, but lately have been as high as 100 mcg due to mitochondrial dysfunction, so it's important to find the dose right for you. And go by your symptoms, not what the labs say.

Good luck!


Hi learner,

Can I just ask, do you feel well now on just T3 and how many times a day do you take it?



I was on 37mcg once daily for 4 years. I have other things going on with my health now, so at the moment, I'm taking 25mcg at 10am and 2pm, for a total of 50.

I tried taking T4 and T3 a few months ago, but my doctor didn't think I was benefiting, so I'm just on T3.

My daughter was on T3 once daily, switched to Armour and switched back to 25mcg T3 once daily. The doctor just added a little T4.

Our doctors are listening to our symptoms and adjusting as we need it.

All the best to you in your journey. 😃


I think that it probably is the way to go - just at the moment we are in the middle of tests for my husband which is causing me some stress I'm sure and I've been interested to see that stress causes inflamation. Quite definitely last year the inflamation caused by reactive arthritis was enough to make me very poorly on the thyroid front. It is so sad that the faith I had in the GP was totally destroyed by the very poor response I had then. Diagnosed eventually due to my own research and paying to see a rheumatologist - everything is looked at in isolation and impossible to condense into an appointment. The thyroid induced palpitations I think they want to see as A fib and is very easy to see how you end up on medication that's not needed because of the narrow outlook (lack of knowledge) at the GP practice.

I am keen to start T3 but want to get through these tests for my husband - I'm supplementing on various fronts D3, B12, folate and hopefully we'll get ourselves well - is odd isn't it they are happy to let my TSH at 5.6 carry on despite taking 125 thyroxine but no doubt if I present at less than 1 alarm bells will sound 😕


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