Thyroid UK
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When to take levothyroxine and taking before blood test

HI All. Im new here :-) and this a bit of an essay to bombard you with as I vent a little! My 13 year old daughter has been on levothyroxine since being diagnosed with hashimotos and hypothyroidism at aged 11. I always get a print of her tests and use these to monitor any changes such as emotional/weight etc. Intially we approached the dr as I knew something was wrong when she just kept gainIn g weight and having constant toilet troubles despite a very healthy lifestyle (both her dad and I are in the health and fitness industry) she has always eaten well and been active so we knew it just wasn't right. Turns out it wasn't and I'm thankful that I had a good gp that bothered to test her!. Despite her thyroxine dose of 100mcg her weight keeps increasing and she is now 3 stone over weight. she has tried everything gluten free. Dairy free. Low carb. High protein and we are now looking in to paleo. She is on a 1300 cal food intake a day and under a dietitian that i insisted upon so they could look at my months of food diaries I'd been keeping . She said she couldn't suggest anything else!. My daughter walks an hour 5 days a week and does sports 4 times a week. She has trouble sleeping at night and no energy in the morings at all, she has a blocked nose most of the tme and bad skin (although that could be her age) she has a degree of fatty liver caused by her weight and a degree of insulin resistance. She needs to lose weight as they keep saying. I'm looking in to asking her endo about possibly adding t3 to her levo as ive read a lot on this combo making people feel so much better, but I just know I will hit a brickwall (from reading others battles with the NHS). Also slightly worried that she may experience side effects that she may not understand like a racing heart, possible anxiety etc.

I've been fighting with them now for over a year as I noted when her tsh level was 0.49 she began losing weight had great energy and was so happy...Very slowly this changed again excessive Weight gain and her TSH was up to 3.0 but to the endos it was within range so she was fine. Last check was 1.71 and they sent me away. The top tsh range at my hospital is 5.0. Her tsh jumps around alot to the top end. She's never been back to that happy place of 0.49.

Researching on the net alot of people seem to have switched to taking their levothyroxine at night. I've started doing this this week. She eats by 6.30pm and takes meds at 10.30. Maybe that will help with energy levels as it has for others.

Has anyone else here made the switch?

Also she used to take her thyroxine at 8am and would have bloods at 9am we were told it made no difference if she took it or not so we just kept to her routine.

Any advice on this also...does it make a difference?

Due to see gp to check her vit d b12 full iron and thyroid levels again next week as it's been 6 months since last routine check. All these were normal ranges 6 months ago. But it worries me as she has gone from mid tsh range to way out the bracket within 3 months before. I only knew because id done private tests imbetween drs visits as id noted another change in her weight and wellbeing. The tsh results came back high so I yet again went back to the GP for them to retest and confirm they needed to increase dose again.

Something is definitely still wrong and I won't stop till I get her to full health.

Thank you so much for reading :-)

Any advice or recommendations very welcome.

A dseperate and frustrated mum! X

8 Replies

Taking her levothyroxine at night will avoid any fluctuations due to variable absorption due to food. Absorption can be slightly less at night but this will show up in the blood test and adjusted for. So, nighttime is better.

Taking levothyroxine on the day of the blood test will have an effect of a few percent on the result. However, you should leave at least a couple of hours before taking the blood otherwise it can give a misleading result. If the blood is being taken early morning I would take the levothyroxine afterwards.


Welcome to our forum and I am really sorry your daughter, at such a young age, has to cope with hypothyroidism.

First, weight gain is a clinical symptom of hypothyroidism and my personal view is that dieting isn't the way to go, if thyroid hormones are the root cause of weight gain. I shall give you a link about all of the clinical symptoms.

We read (if not hypo) that exercise etc to raise metabolism will help with weight loss plus dieting. Considering that hypothyroidism has lowered our metabolism so much that weight is gained (not by everyone but is a very common complain). We really don't want to lower it further by dieting. Also exercise can reduce our T3 which is the active hormone which is needed in our receptor cells for us to function.

New research has shown that a combination of T4/T3 is best for many people. T4 (levothyroxine) is inactive and its job is to convert to T3 but few doctors will test Free t4 and Free T3. T3 is the only active thyroid hormone but when people get to an optimal or combined dose they can have a symptom-free and healthy life.

Unfortunately, the modern method of diagnosing and treating may not be the best. Blood tests should only be a guide but I think symptoms should be a priority as that is what makes us feel unwell - clinical symptoms.

The BTA has decided to withdraw T3 from being prescribed due to the exhorbitant rise in price.

Blood tests should be the very earliest, fasting (she can drink water) and she should miss night dose before test and take it afterwards and also take her night dose as usual.

Also get B12, Vit D, iron, ferritin and folate tested and get a print-out of the results with the ranges and post for comments.


no idea who told you it was fine to take levothyroxine at 8am and be tested at 9 am

its precisely why she is still ill

its utterly vital that

blood tests are early morning

they are fasting and only water to drink

never never never take any thyroid meds in the previous 24 hours

in a correctly treated hypothyroid patient

TSH should be 1.0 or below

free t4 and free t3 should both be in balance and in the upper quadrant of their ranges

so t4 would be more like 19 or 20 and T3 around 5.8 or 6.0 on the usual ranges )

email for a copy of Dr Tofts PULSE article and use that as evidence for why your daighter is still ill

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Sorry to hear that your daughter is going through such a tough time.

Can you post her blood results on here as what the Drs tell you is normal and the reality are often very different.

Yes THS needs to be under 1 for us to feel well. At 3 I feel like I've been run over by a bus.

I'm guessing she is either undermedicated or not converting T4 to T3 which is hugely common and why a lot of us add T3 or switch to NDT (natural Dessicated thyroid)

T4 is a prohormone and T3 is the active hormone five times more active that T4.

Drs do two weeks training on the thyroid in med school so they have little or no idea!!

Things that have helped me;

NDT (has made me feel human and brought cholesterol right down)

Vit D needs to be 60

B12, over 600 some say between 900 & 1000 the Japanese start supplementing at 500 under 500 can start to cause neurological changes.

Test Folate and Ferritin, magnesium and selenium are good to know levels too. If she's having trouble sleeping that can often be magnesium but don't supplement without knowing levels.

Gluten and casein free is a must.

Gluten and Casein look like the thyroid to the body (molecular mimmickry) so when you eat and they get in to your bloodstream via your gut (leaky gut) your T cells are sent to attack as are foreign but then also attack your thyroid.

Turmeric (add black pepper as helps absorption) and cinnamon help inflammation. I pop in a smoothie every morning along with collagen powder as helps heal the gut.

Avoiding nightshades potato,tomato,aubergine...I feel like I'm recovering from flu with potato and my joints really hurt.

Are you in the UK?

Private testing may be an idea to get the full picture.

Bluehorizonmedicals or medicheck

Thyroid plus eleven, twelve or fifteen are all good comprehensive tests.

Dr Datis Khazzarian has brilliant books and a website.

Chris Kresser website for leaky gut.

Susan Blum Auto Immune Recovery Plan is highly recommend to sort out your daughters food sensitivities.

Good luck.


Unfortunately your background in health and fitness won't help your child at this point as the eating habits of a fit person or someone just overweight will not work for a hypo person. diagnosed at 11 and only 13 now and you've tried how many different "diets" 4?. thats hardly enough time to sort out if they help or not. I suggest you make sure she just eats clean, healthy meat and veg, stop the calorie counting and the 4 times a week exercise and once you have her next bloods done ( please follow the no meds, fasting advice given before meds) then please come back here with a full set of test results including ranges ( as doctors within range or normal levels mean nothing) only then can the people on here begin to help you to try get your daughter on the way to feeling better, there are so many factors to take into consideration that the information you have given isn't enough to help you properly, And its not always as simple as a medication increase sadly, its a bloody minefield with many twists and turns but hopefully the people on here will be able to guide you once they have the full facts and figures, please try not to stress too much or you too could become ill and thats the last thing you need, sending virtual hugs

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Hi thankyou so much for your reply. I'm so happy to have found this site. I realise that I may sound awful about her diet and exercise like I'm very regimeted But the gluten and diary was done together as an elimination experiment when working with a nurtitionist. We did it for about 7 months with no change to her symptoms and no reduction in antibodies although as you say that may not have been long enough and w. that were noticeable on the outside. She was tested for leaky gut on the nutritionist recommendation and a few other gut tests that showed no issues. The nutritionist said her video was low after seeing the dr result print out of 30. So we started on Vit D drops. I was kind of told off by her endo for going to a nutritionist and cutting out gluten etc. We started her bk on it slowly and she had no reaction same with dairy. We do eat as clean as possible and any carbs are low GI. Her exercise is stuff that she does in general routine so she walks to school and back and is active at school with sports that she choses a to do. At one point I thought maybe it wasn't enough and we started extra exercise sessions which didn't last long as I realised she couldn't cope. I will go back to the g/f and diary elimination. I'm also getting her tests done on 25th for all those important vit and minerals and thyroid. I will ask for t3 test to. If they won't I've been recommended a few specialists privately I just need to check they see children. I'll definitely post her results up and any advice on them would be fantastic. Thak you again for your support x

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Sorry...I am writing on my phone and hit send without checking for typos! Hope the last reply made sense! :-)

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OK things that work for me! Weight, you need a low Glycemic diet irrespective of the calories per day.

Sleeping problem, it's very common that hypothyroid people are low in zinc, zinc lowers cortisol, I take 30mg 3hrs before bed to be able to get to sleep.

If the TSH is yoyoing odds are the adrenals are involved as the thyroid compensates for flagging adrenals. If this is the case she needs amino acids as the adrenals thrive on them, plus get her GH (growth hormone) checked too. In my case when I introduced amino acids the fatigue significantly reduced the remaining ING fatigue I believe is due to the fact I've been inactive for 3-4yrs, need to get fitter again Oh the coming pain barriers 😢

Hope this helps,

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