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Thyroid UK
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Newly diagnosed underactive thyroid

Hi. Just been diagnosed and had a reading of 18. I've been put on 100 micrograms of levothyroxine. Originally went as had an aura migraine and my eyelid has drooped. ( only get these migraine after playing hockey on a hot day. Put them down to dehydration. (Have suffered from both types of migraines over the years) usually back to normal after 40 mins but took 2 days to feel normal. Was told I would have more energy and lose weight. (Although I'm not really overweight) feeling spaced out and actually slept for 90 mins in the middle of the day! Wanting to know how other people are feeling/coping

15 Replies

Welcome to the forum, Bystander.

I expect 18 was your TSH result. 18 is high but 100mcg is a decent dose and should bring it down in 4-6 weeks.

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 and oestrogen.

It takes 7-10 days for Levothyroxine to be absorbed before it starts working and it will take up to six weeks to feel the full impact of the dose.

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.

Most people will find symptoms resolve after their TSH drops to around 1.0 with FT4 in the upper range but symptoms can lag a couple of months behind good biochemistry.



I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


Thank you very much for your reply. It was very helpful :-)


I was taking vitamin supplements with iron. Evening primrose oil and black cohosh thinking my mood swings and tiredness were to do with the menopause. I have stopped taking these and took my levothyroxine in the night as I'm feeling fairly spaced out.

I will try doing as you suggest now and take it in the morning. Do you suggest I stop all the supplements or just take them later in the day



Levothyroxine can be more effective when taken at night, there's no need to switch to taking it in the morning unless it suits you better.

You can continue taking supplements and iron if you take them away from Levothyroxine as I outlined above.

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Hi Cutter - I notice you say the optimal time is: 1 hour before food; 4 hours before calcium.

I take my levothyroxine as I wake up then try and postpone breakfast/caffeine for 30-60 minutes minimum (in line with pharmacy instructions) - but should I also be avoiding dairy (calcium) in the morning?

I see now why some people take it in the middle of the night!




Take Levothyroxine 4 hours away from calcium supplements. It's fine to have dairy 1 hour after taking Levothyroxine. You should avoid coffee for at least an hour after taking Levothyroxine as it can reduce absorption of Levothyroxine by up to 40%.

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Great - thanks for the clarity !


Thank you. Extremely helpful :-)


Many of us find taking Levo at bedtime, (or in middle of night) seems to work better. Or can just be easier, if also taking a lot of supplements in day time.

Important thing is to always take on empty stomach, just with water and nothing for at least an hour after.

Also much better to always stick to same brand of thyroxine. Pharmacies can try to palm you off with different brand every time, (or sometimes even in same bag!). Always check before you leave that it is same one as normal.




Long research article - final conclusion paragraph below

"In conclusion, bedtime intake of levothyroxine in our study significantly improved thyroid hormone levels. This may be explained by better gastrointestinal bioavailability at night or by less uptake interference by food or medications. As shown in this study, bedtime administration is more convenient for many patients. Clinicians should inform their patients about the possibility of taking levothyroxine at bedtime. A prolonged period of bedtime levothyroxine therapy may be required for a change in QOL to occur."

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Great. Thanks for advice. All replies with suggestions are greatly received :-)


Are there any major dos and donts......


Read as much as you can .....on here or elsewhere.

When you get bloods retested, be good idea to ask GP if they can test thyroid antibodies. There are two sorts TPO Ab and TG Ab. (Thyroid peroxidase and thyroglobulin) Both need checking, if either, or both are high this means autoimmune thyroid - called Hashimoto's the most common cause in UK of being hypo.

(NHS rarely checks TPO and almost never checks TG. NHS believes it is impossible to have negative TPO and raised TG. It's rare, but not impossible, there are a few members on here that have this.)

Make sure you always get the actual figures from tests (including ranges - figures in brackets). You are entitled to copies of your own results. Some surgeries make nominal charge for printing out.

Alternatively you can now ask for online access to your own medical records. Though not all surgeries can do this yet, or may not have blood test results available yet online.

When you get results suggest you make a new post on here and members can offer advice on any vitamin supplements needed

If you can not get GP to do these tests, then like many of us, you can get them done privately


Blue Horizon - Thyroid plus eleven tests all these.

This is an easy to do fingerprick test you do at home, post back and they email results to you couple of days later.

Usual advice on ALL thyroid tests, (home one or on NHS) is to do early in morning, ideally before 9am. No food or drink beforehand (other than water) If you are taking Levo, then don't take it in 24 hours before (take straight after). This way your tests are always consistent, and it will show highest TSH, and as this is mainly all the medics decide dose on, best idea is to keep result as high as possible

If you have Hashimoto's then you may find adopting 100% gluten free diet can help reduce symptoms, and lower antibodies too.

You do not need to have ANY obvious gut issues, to still have poor absorption or gluten intolerance

Best advice is to read as much as you can. Vitamin and minerals levels are very important, but standard NHS thinking, doesn't at the moment seem to recognise this.

You will see, time and time again on here lots of information and advice about importance of good levels of B12, folate, ferritin and vitamin D, leaky gut and gluten connection to autoimmune Hashimoto's too.


Thank you very much! It's so nice to know people out there who have experience of these conditions and are willing and able to give advice.

The one gut issue I do have is a lot of heartburn. Is this significant?


Yes, low stomach acid is very common. Apple cider vinegar (with mother) or Betaine HCL may help

Search "low stomach acid" on here you will find loads of posts on how to treat and how to test if low not high acid

(GP's very often just assume it's high acid and dole out PPI's - that is the last thing you need...would make it worse.....and then also reduces nutrient uptake from food even lower )

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Thank you. Very much appreciated advice


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