Thyroid UK

TSH over 100, undetectable T4 & T3

I am newly diagnosed and new to this forum. Just wanting to ask for any input concerning my levels. TSH was 103 (reference range 0.4-4.0) and free T4 was reported as "undetectable" <0.35 (reference range .8-1.9) with Total T3 reported at "undetectable" <40 (reference range 82-179). Saw endocrinologist immediately who diagnosed me as hypothyroid, and put me on 100 mg levrothyroxine. I have been on it for five weeks. Feeling better, but can't test again for another 3 weeks. She said to only have the TSH retested, but from what I read here, I should have other things tested as well. How long might it take to get me to the correct levels? And is there generally memory/cognitive improvement when all gets regulated? I am a 59-year-old female. Thanks for any input/suggestions.

11 Replies

Some patients do OK with just the TSH being tested but definitely not all. It will take about three months to get your dose reasonably close and then some more time before you fully recover. It's important to let your doctor know how you are doing. If you are not reasonably well in a few months time ask for a full thyroid panel, although you will probably have to get a private blood test as GPs are often unable to get them done.


Thanks for the reply. I was hoping by now I would be back to normal. Some symptoms are better, but not consistently. I'm most worried about my memory lapses and mild confusion. Is it typical for that to improve?


I agree with jimh111. I would wait a bit for things to settle down. Private blood tests are reasonably priced considering the peace of mind you get in return. My first and only private blood test showed T4 in the upper end of the healthy range and slightly low T3 so I am looking at treating this nutritionally then retesting to see if anything has changed.


Thanks for your reply. This is all new to me and to be told that my levels were "off the charts" is rather frightening. And disappointing it takes so long to re-test to see if the meds are kicking in.


If you are new there's a bunch of reading I would advise you to do. Specifically regarding your nutrient levels! Its really vital that they get tested so as to help give you insight into what your body is - or isn't - doing well (i.e. Converting your dose to the necessary T3). We often have absorption problems and gut issues so and this will show up in your lab results. And our ferritin, Folate, D3 and B12 nutrient levels are really important for thyroid function. Then your next labs need to be done after fasting (water OK) and 24 hours without Levo - this gives us our most accurate results. If you need private labs done you can order these via this Thyroid UK link.

And start out with these links to read up on nutrients and the need for optimal levels:


Thank you for this information and the links. Also good to know about no Levo before the next blood test. I was wondering about that.


Hi - you didn't become hypothyroid overnight and unfortunately there is no overnight solution either. You will see over and over again in this forum that dose increases can only be done every 6-8 weeks and only by a small amount each time - 25mcg. That is because thyroid hormones control the speed that everything in your body runs at, and to add too much too quickly would be a dangerous shock to the system. What happens when you increase a dose is that your body must convert the t4 you are taking - an inactive storage hormone- into t3 - an active hormone - and this predominantly happens in the liver. Once that process has started and the body realises that it has more t3 available, it starts to open up receptors on every cell in your body. When you are hypo these are put into a dormant state in an effort to conserve energy and make the most effective use of what you do have in a bid to protect essential systems like heart and breathing to keep you alive. It takes time for the body to gradually open these up, hence alleviating some of your symptoms.

It will get better and you will feel better, but it is a process and it does take time, sometimes many months, but it will happen. At your level, TSH only should be enough to indicate that things are going the right way. Once you get a good bit closer to the target of around 1 or less for TSH, then would be the time to use more measures as well to fine tune your dose.

In the interim there are things you can do to help yourself. You have been given many references above. Reading and learning so that we become familiar with and gain understanding of our own condition enables us to take control of our own health. This can be vital when we may well run up against doctors making bad decisions about our care through lack of knowledge of thyroid.

Hang on in there.

Good luck



Thank you!


One of the most common symptoms reported by people with hypothyroidism is 'brain fog', so you are not alone. Most people find things improve as their levels of thyroid hormones are improved.

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When you are trying to reduce TSH from very high levels (like your 100iu/mL) it's fine to just measure TSH. It is when you are getting to a TSH of 1.5 and under that you must measure other factors (like Free T3, Free T4, rT3, antibodies etc).

This is actually the crux of the misconception by the medical profession. The TSH-only measurement is perfectly fine over most of its scale - it's a good straight forward algorithm. However, you cannot apply that algorithm once you get to 1.5 and below! I do not know the nature of the curve (line?) below 1.5, but things go out of whack (a technical term) at the lower levels.

I think you will be fine for the next three weeks at 100mcg and then, according to your TSH level, you may be told to up your dose - and thereafter until you reach 1.5 iu/mL - and then..... keep reading this forum! But you will be happy to know that Levo does work for lots of people, I used to be one, and I hope you are one. Let us know how things go.


Thanks. That is what my endo said, so it's reassuring that she knows what she is doing.


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