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Thyroid UK
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Ten days into low level thyroxine and nothing

Hi all, I may be expecting a miracle but have been taking 25 mg for underactive thyroid hashimotos now for two weeks and don't feel any different. My last TSH was 7 which was eight weeks prior to starting thyroxine finally so not sure if it may be too low a dose. Would appreciate others' experiences on time it takes to notice a difference? Have repeat bloods in four weeks to check but ??

Many thanks

4 Replies

Unfortunately, it is a slow process. 50mcg is usually the starting dose unless we are very frail with a heart disease. It takes about six to eight weeks to build up in your system and an increase of 25mcg thereafter around every six weeks until you feel well. Not until your TSH pleases the doctor.

It has taken us years to become hypothyroid so it stands to reason it has to be a gradual increase.

Levothyroxine should be taken first thing with one full glass of water (usually when we awake). Others may take a bedtime dose as long as they've last eaten about 2.5 to 3 hours previously.

When having a blood test next day you have to allow a 24 hours gap between last dose and test which should also be fasting (you can drink water). If taking a night dose, miss this and take after test and night dose as usual.

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It's too early to expect any improvement. It takes 7-10 days for the 25mcg Levothyroxine to be absorbed before it starts working and up to six weeks to feel the full impact of the dose. 25mcg probably isn't sufficient dose but thyroid replacement has to be introduced gradually. If your blood test shows your TSH is still high your dose will be increased.

The goal of Levothyroxine is to restore the patient to euthyroid status. For most patients that will be when TSH is 0.4 - 1.0 with FT4 in the upper range. FT4 needs to be in the upper range in order that sufficient T3 is converted. Read Treatment Options in thyroiduk.org.uk/tuk/about_...

For maximum absorption Levothyroxine should be taken with water 1 hour before, or 2 hours after, food and drink, 2 hours away from other medication and supplements, and 4 hours away from calcium, iron, vitamin D supplements, magnesium and oestrogen.

You should have a follow up thyroid test 6-8 weeks after starting Levothyroxine. Arrange an early morning and fasting (water only) blood draw when TSH is highest, and take Levothyroxine after your blood draw.


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Hi. I have just finished 4 weeks on 50mg and can't say as I notice any difference yet so like the others say it can take a while.

My next Endo appointment isn't due for about another 8-10 weeks still and I have been told to get my next tests done when the appointment letter arrives so I won't know what effect it has had on my numbers for a while either.

I feel your frustration too but I am starting to come to terms with the wait.


Thanks for all your responses as ever ...... this is such a great resource for us beginners...... good to hear not to expect a lightbulb moment and it takes work!


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