Hi, I was diagnosed with hypothyroidism 9 months ago and still trying to get my Levo dose right. I recently heard that I shouldn’t take Levo for 2 days prior to my blood test. My test is on Friday (2 days time) so should I not take Levo today and tomorrow until after the test at 2pm?
Thanks so much!
Welcome to the forum SleepingDisco.
'I recently heard that I shouldn’t take Levo for 2 days prior to my blood test.'
That is very defintely incorrect. Two days without medication is too long and will give a false reading.
What time of day do you usually take your levothyroxine?
thanks so much for taking the time to reply to my post. I usually take it between 6-7am. Based on all the replies I’ll definitely keep taking it, but hold off on test day until after my bloods have been taken (2pm)
And then make sure I book future tests for as early in the day as poss.
I’ve read some interesting articles about taking Levo in the evening and that it doesn’t make much difference to do so - do you know much about this?
Thanks again
Some people find taking levo at bedtime works better for them. Others don't. 
It can be convenient to take it at night, for example if you have other medications that need to be taken in the morning.
It is often suggested that bed-time dosing results in slightly better absorption. It also seems slightly closer to the pattern healthy people have.
I have always taken my levothyroxine at bed-time.
For that reason, I cannot compare with taking in the morning.
Before diagnosis, my sleep was badly disturbed. Typically, I would fall asleep fairly easily. Then wake up after something like half an hour to two hours. Once woken I'd be unable to get back to sleep - often till dawn, or at all.
Once I started on levothyroxine, my sleep slowly improved. By the time I was taking an adequate dose, bad nights were unusual - just an occasional night where I might wake up for a while. Now, after years, I sleep very easily and deeply and rarely wake at all. If I do, I get back to sleep quickly.
We have some who prefer it; we have others who prefer other times. See our poll:
healthunlocked.com/thyroidu...
Some papers which discuss taking levothyroxine at different times - such as bed-time.
Levothyroxine Replacement and Ramadan Fasting
pubmed.ncbi.nlm.nih.gov/237...
Effect of L-Thyroxine Administration Before Breakfast vs at Bedtime on Hypothyroidism: A Meta-Analysis
pubmed.ncbi.nlm.nih.gov/320...
Morning vs. Bedtime Levothyroxine Administration: What Is the Ideal Choice for Children?
pubmed.ncbi.nlm.nih.gov/303...
A Crossover Study Evaluating Effect of Timing of Levothyroxine on Thyroid Hormone Status in Patients of Hypothyroidism
pubmed.ncbi.nlm.nih.gov/313...
Effect of Timing of Levothyroxine Administration on the Treatment of Hypothyroidism: A Three-Period Crossover Randomized Study
pubmed.ncbi.nlm.nih.gov/300...
Alternative Schedules of Levothyroxine Administration
pubmed.ncbi.nlm.nih.gov/256...
Thyroid Diseases and Ramadan
pubmed.ncbi.nlm.nih.gov/228...
Pharmacotherapy: Hypothyroidism-Should Levothyroxine Be Taken at Bedtime?
pubmed.ncbi.nlm.nih.gov/213...
Effects of Evening vs Morning Levothyroxine Intake: A Randomized Double-Blind Crossover Trial
pubmed.ncbi.nlm.nih.gov/211...
Timing of Levothyroxine Administration Affects Serum Thyrotropin Concentration
pubmed.ncbi.nlm.nih.gov/195...
Effects of Evening vs Morning Thyroxine Ingestion on Serum Thyroid Hormone Profiles in Hypothyroid Patients
pubmed.ncbi.nlm.nih.gov/172...
Previous posts:
Levothyroxine - Switching to night
healthunlocked.com/thyroidu...
Levothyroxine Medication Query
healthunlocked.com/thyroidu...
Wow, so much info - this is great, thank you!
I'm still getting my head around it all. I battled with my GP to increase my dose as I still had loads of symptoms on the 50mg and then 75mg doses I was initially and then prescribed. I've been allowed to try 100mg for 3 months - hence me wanting to get the blood test right on Friday as I'm worried he'll make me drop back down if the numbers aren't 'right'. He said there's a big risk of osteoporosis if I over-medicate on levo..
But I definitely feel a bit better on 100mg; the weight gain has eased a bit (although not reversing yet!) (I put on a 1.5 stone with untreated thyroid, and have never had to really worry about weight gain before).
Just the tinnitus now - it's so bad atm! Constant ringing in both ears - drives me mad!
Thanks again for your help
Glad if it does help.
Tinnitus - yes. I have that regardless!
(You are expressing doses in mg - milligrams - they should be in mcg - micrograms. One thousandth as much! Helps to be right when talking to medics.)
it does indeed, thank you. And yes, I’ve heard (!) tinnitus is something that we just have to get on with unfortunately, regardless of Levo levels etc. 😩
No that is wrong.
Most want to measure FT4 when it is at its lowest daily level. If you take 1 dose daily ie every 24 hours then your low point will be at the 24 hour mark just before you take your next dose and it starts to build up again in your blood.
So you take your last dose of levo 24hours before your blood test if that is what you want to do.
The peak level of t4 in the blood comes 2 to 4 hours after you take a dose of levo. So it is best to avoid a blood test during peak time as it is unrepresentative of blood levels the rest of the day.
It is up to you to find what timings suit you, then stick with the same protocol for all your blood tests so you compare like for like.
Tsh is higher early morning so you will see advised here to get earliest blood test possible. However some surgeries dont do early morning thyroid tests. Also for some folks tsh is no longer important so we don't bother about having bloods done first thing. My blood tests are always around 2pm for example. I also split my daily levo dose. My longest gap in my daily 2 dose routine is 16hours so I leave a 16 hour gap between my last dose of levo and the blood test.
thanks for taking the time to reply to my post. Some really interesting info here. I always have my blood tests done at 2pm, but wonder if I should switch this to early am from now on…
Thanks again
If your doctor judges your dose by looking at your tsh rather than looking at ft4 and ft3 levels then you want to get the highest tsh you can. So early morning and only water to drink as some food and drink might lower tsh slightly. If like me the dr ignores the tsh then you can have later blood tests.
we would ALWAYS recommend getting thyroid levels tested early morning around 9am …..and last dose levothyroxine 24 hours before test
TSH has pronounced circadian rhythm and drops to its lowest point in day after lunch
Suggest you rebook test for an early morning appointment
How much levothyroxine are you currently taking
Do you always get same brand levothyroxine at each prescription
ESSENTIAL to test vitamin D, folate, ferritin and B12
Plus thyroid antibodies for autoimmune thyroid disease
About 90% of primary hypothyroidism is autoimmune thyroid disease, usually diagnosed by high thyroid antibodies
Autoimmune thyroid disease with goitre is Hashimoto’s
Autoimmune thyroid disease without goitre is Ord’s thyroiditis.
Both are autoimmune and generally called Hashimoto’s.
Low vitamin levels are extremely common when hypothyroid, especially with autoimmune thyroid disease (Hashimoto’s or Ord’s thyroiditis)
20% of autoimmune thyroid patients never have high thyroid antibodies and ultrasound scan of thyroid can get diagnosis
In U.K. medics hardly ever refer to autoimmune thyroid disease as Hashimoto’s (or Ord’s thyroiditis)
Recommended on here that all thyroid blood tests early morning, ideally just before 9am and last dose levothyroxine 24 hours before test
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
Private tests are available as NHS currently rarely tests Ft3 or all relevant vitamins
List of private testing options and money off codes
thyroiduk.org/getting-a-dia...
Medichecks Thyroid plus antibodies and vitamins
medichecks.com/products/adv...
Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins
bluehorizonbloodtests.co.uk...
If you can get GP to test vitamins and antibodies then cheapest option for just TSH, FT4 and FT3
£29 (via NHS private service ) and 10% off down to £26.10 if go on thyroid uk for code
thyroiduk.org/getting-a-dia...
NHS easy postal kit vitamin D test £29 via
Only do private testing early Monday or Tuesday morning. Watch out for postal strikes, probably want to pay for guaranteed 24 hours delivery
Link about thyroid blood tests
thyroiduk.org/getting-a-dia...
Link about Hashimoto’s
thyroiduk.org/hypothyroid-b...
Symptoms of hypothyroidism
thyroiduk.org/wp-content/up...
But if you dose levo more than once a day a 24 hour gap will give a false low because you never normally have a 24 hour gap between doses.
levothyroxine last at least 7 days in cells….but test looks at Levo in blood…..So your looking for 24 hour gap between last dose levothyroxine and blood test
Delaying an evening dose levothyroxine until morning 7-8 hours later than normal won’t affect TSH
And if normally split dose ….half morning and half bedtime it will make even less difference
Blood Test. I take Levo at night.
blood tests post or pre Levo?
Do I listen to endo telling me I have to take levo and liothyronine 3 hrs before blood test?
Should I take my Levo at night when having blood tests the next day?
Take levo before or after blood test?
