Thyroid UK
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Does levothyroxine work?

Hi I have an underactive thyroid for about 16-17 years it started for no reason that I know have had various dosages of levothyroxine but have never really felt right. Recently I have felt really tired can't be bothered with anything, bad tempered, hot sweats, feeling dizzy and mood swings,I have been asked (in a nice way ) if I am ok as other people at work feel i am being funny or even rude to them. I am having a repeat blood test after 12 weeks which seems a bit odd as i usually only have a yearly one.I am not sure what the blood test reveal, can anyone help? if the levothyroxine is not working could this be the cause? I hope this is not seen as a moan and can I ask the GP for a note for work to explain why I am feeling this way. Thanks for any replies

6 Replies

Please don't feel that you are having a "moan". The potential for you to be overwhelmed by responses on this forum from people who know exactly how you feel is ENORMOUS!

Yes, levo does work for some people, but you have other options if it is not right for you. Have a look here on the main website:

Also do you have your latest test results and reference levels. Your doctor can provide these. Post them on here for us to have a look. There may be other tests that could be carried out too. Have a look here:

Jane x


Hi Thorn. Yes, levo does work for some people, but you have to be taking enough of it for it to make any difference. You don't say what dose you're on, but it might not be enough for you. The problem is that doctors are reluctant to give high enough doses because they go by the TSH test, which is deeply flawed.

Hugs, Grey


Great advice from Jane and Grey.

There are a couple of other things to think about too. It's very common to have "ok" levels of iron, but this is often not enough in reality. It would be good to get your serum iron and ferritin (stored iron) checked. Your iron needs to be a good level within the range, nowhere near the lower end of the range. Ferritin is best above 70 for women and higher for men. Iron is very important for your body to be able to use thyroid hormones as well as its other roles.

Many people with hypothyroidism are deficient in vitamins and minerals. As well as iron, vitamin B12, folate and vitamin D are other common ones. The NHS level of normal is too low for B12. In Japan, the minimum level is around 400 (200 for the NHS!) so it is wise to aim for at least that and preferably a bit higher. Vitamin D deficiency is very common in the UK so this should be tested. There reference ranges for this are ok. These deficiencies can also cause symptoms similar to hypothyroidism, as can iron deficiency even without anaemia.

Another thing is low cortisol. This is known as adrenals fatigue (rather than the serious condition called Addison's disease). Although the WHO recognises this as a big problem in the western world, the NHS doesn't recognise its existence. Your best bet would be to do a search for "adrenal fatigue". You will find many sites about this. Most of the treatment are self-help measures. It is only in more severe cases that prescription hydrocortisone is required.

I know many people who are very well on levothyroxine (unfortunately I am not one of them) but, as Jane says, there are other options if you find it doesn't work for you.

Carolyn x


Seems to work for me. :-)



Hello there,

I'm sorry you're feeling so bad lately. I hope you don't mind if I ask for some more information about you - it would allow us to give more informative replies :)

>Recently I have felt really tired can't be bothered with anything, bad tempered, hot sweats, feeling dizzy and mood swings.

How recently has this happened? You said you've been on levothyroxine for a long time. Has your dose been altered in the last few months? Also, may I ask whether you are male or female, your age (or approximate age if you prefer), whether you have a history of any other medical problems, and whether you are on other medication of any type, and if so, has that been changed recently? When you went for your blood test, do you know if your GP tested anything else or just your thyroid?

Please ignore any of my questions that you do not feel comfortable answering.

>I am not sure what the blood test reveal, can anyone help?

I expect your GP tested the level of a hormone called TSH, and possibly T4. These tests give an indication of whether (or not) your levothyroxine dose is appropriate to your needs. Based on this blood test and your symptoms, your levothyroxine dose may need to be adjusted. Your doctor must also consider other possible causes of your symptoms.


Personally, no, levo does not work. I think that some doctors are good at selling the myth that because its cheap it does the job. I am a volunteer across several charities and I must have met around 40 ish people who are hypo none of whom are well and still suffer symptoms. They rave however, about how wonderful their doctors are before telling me about their hair falling out in handfulls etc. It is a sad state of affairs that people are denied the compassion and correct medication to help them!!!


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