Thyroid UK
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How long for eltroxin to work?

Hi all,

I have been on eltroxin 50mcg for five months. I felt an effect within days of taking it. My stamina improved and I felt I had come out of a coma. However the physical tiredness has lingered. I have aches and pains in my hands and feet on the last three months and am having lots of trouble with constipation. I also have carpal tunnel syndrone which improved initially but is now coming back. My gp said as I am in range now tsh from 5.6 to 2.4 that is all I need.Can it take this long to work?

7 Replies

This is a much-repeated story.

It appears that after a while, the 50 mcg you are taking reduces your own production of T4. So what starts as an addition of 50 mcg starts to become partly a replacement and partly an addition. So a higher dose is required.

I feel this is more or less what happened to me. Began on 25, then 50 followed by 75. Until very recently I have been taking 100 mcg a day. (Though have very recently been alternating 100 and 50 because I have been feeling slightly over-dosed.)

If your TSH is actually reflecting your thyroid levels, many suggest that it should be lower than 2.4. Certainly with your description of how you feel, there is room for an increase without thinking you would be over-dosed.

There is no reason on the planet to think that a dose, once set, should not be adjusted as and when required.

I hope you are aware of taking the levothyroxine well away from food, drink other than water, supplements and other medicines? Not doing so could also impact on your absorption and hence its effect.



Also meant to write:

Some benefit can be quick. Some will be slower. Some can take a very long time to come through.

I have often suggested that it might take as long to recover as well as you can as it took to go downhill. This is not meant to be disheartening - but rather to suggest that further improvement might still be possible even after a long time.



Thanks Rod. That is what I have been thinking but wonder of my gp will see it that way. I set my alarm an hour before wake up time to take the eltroxin on an empty stomach.


I would not wish to do that. One reason I take mine at bed-time! :-)

By the way, if you click on Reply to this your response will get indented under the post you are replying to. And the person will get an alert that you have replied!


My docs said it would take 6 months to kick in. After 6 months I was still struggling, they then told me it could take up to a year to properly work . When it finally started to work I felt like a fog had been lifted and had energy for the first time in years ! My reading is now at 19 which they say us 'in range' but I am feeling pretty bad again. When my reading was at 11 I started to feel better...I'm thinking of asking to try something else! I hope it works for you! I don't think people know how hard it is to be so tired all of the time (not to mention other symptoms)! Good luck. :)


Take control of your condition. Read up, go to the doctors armed to the teeth with information and say you would like to explore the option of increasing your doseage, decreasing your doseage, trying something else, whatever YOU feel is appropriate for you. Be proactive. It's what I have done recently and my doctor is being very supportive, well to a degree. I am a great believer in planting a seed!


There are many allopathic and non- to explore. (No need to subscribe to formidable textbook definitions!) Very few understand endocrinology (for eg) other than endos - and same with similar concerns; but you body usage - or abusage - is your intrinsic field to manage.


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