Thyroid UK
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TSH higher after starting levo!

I was dx with hashi in march, TSH at the time was 5ish...started 25mg Levo which brought TSH down to 3-ish in May (FT3 and FT4 were at about 50-55% of the range at the time).

Just got my latest test results today and my TSH is BACK up to 5ish! How is that possible when i am regularly taking the levo?

Doc now wants to double the dose to 50mg. We also want to try to get pregnant and he says I need to wait till the levels come down.

Am quite disappointed as it seems the med is not working and god knows how long I will have to wait before levels come down enough for me to try to conceive :(

5 Replies

The reason is that 25mcg is a ludicrously small dose for most people.

Levo has the effect of reducing the TSH VERY fast. It's good at doing that. That is because the Pituitary Gland, which is where the Thyroid Stimulating Hormone (TSH) is produced, is very, very sensitive to increases in blood levels of thyroid hormones, so it quickly reduces the TSH.

This means that your thyroid will reduce production of natural hormones in response to the TSH drop, resulting in your overall levels of circulating thyroid hormones going down.

For this reason, in a young healthy person, 25mcg of Levo will never be enough. You need an increase as soon as possible.

The meds ARE working, but your own thyroid hormone levels are dropping. This continues to happen until you reach your optimum level and you become stable.


25mcg is such a low dose to be negligible. 50mcg is usually a starting dose and after six weeks get another blood test and most probably another rise.

It is important that your thyroid gland hormones a tip-top and you will have to make sure during pregnancy that you are sufficiently medicated. We all have to read and learn unfortunately in order to keep/get well.

If you fill in a little of your medical history in your Profile, it will give members an idea, i.e. when diagnosed etc. etc. This is a link for information but links within may not work as Dr Lowe died last year.

Always get your blood tests for your thyroid gland as early as possible (TSH is higher then). Don't take levothyroxine until after your blood test. (If you've eaten you must leave 2 hours either side of the medication).

Take meds with one glass of water and wait about 1 hour before eating.

If you take supplements or other medication take about 4 hours apart from levo. Usually supplements have to be taken with food.

Always ask for a print-out of your blood test results from the surgery, we are entitled, for your own records and make sure they have the ranges alongside the results. You can then post them if you have a query for comments.


thanks so much marram and shaws for your replies. I will start the 50mcg tomorrow and pray that my levels have improved enough in six weeks (which is my next blood test) for us to start trying for a baby (am 32 so don't really have a lot to time to wait around... :) ).

For reference my latest results are as follows:

TSH : 5.02 (range .35-4.94)....was 3.2 in May

Ft4: 11.58 (range 9-19)....was 14.87 in May

Ft3: 3.65 (range 2.63-5.7)....was 3.96 in May

Thyroglubin antibody 11 (range <4.1)

TPO: 754 (range <5.6)

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Brenda, TSH needs to be in the low normal range 0.4-2.0 otherwise conception can be difficult and the risk of miscarriage and abnormal foetal development is increased.

50mcg is still a low dose and will probably need increasing to 75mcg/100mcg before your TSH is reduced sufficiently.

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look at this article brendala- about hypothyroid pregnancy and autism/ developmental disorder link . important to feel well first- hope it helps.


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