How long before you notice missed levothyroxine... - Thyroid UK

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How long before you notice missed levothyroxine doses?

Bearfam profile image

How long before you notice missed levothyroxine doses?

I've had some great advice in the past from this site and was hoping I might be able to get some insight. I have experience LD ongoing anxiety and depression I have felt over the past few weeks particularly low. Even though I take citalopram which normally works fairly well. I realised for around 1 to 2 weeks I'd forgotten to take my levothyroxine everyday . I've started taking it everyday and my mood is better. I was also feeling exhausted and feel slight less tired but still not 100%.I was just wondering what other people's experiences of missing doses are.

I take 100mg a day of levothyroxine.

9 Replies

I notice it at once and by the time I had missed a couple of weeks, I would be utterly unable to function despite what the endo tells me.

SlowDragon profile image

Get yourself a weekly pill dispenser

It will take minimum of 6-8 weeks for levels to settle

Recommend you then get FULL thyroid and vitamin testing

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also EXTREMELY important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies....or if under medicated

Ask GP to test vitamin levels

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Is this how you do your tests?

Private tests are available as NHS currently rarely tests Ft3 or thyroid antibodies or all relevant vitamins

List of private testing options

Medichecks Thyroid plus ultra vitamin

Medichecks often have special offers, if order on Thursdays

Thriva Thyroid plus vitamins

Blue Horizon Thyroid Premium Gold includes vitamins

helvella profile image

I have not forgotten my dose for a very long time. But last time I missed one dose, I knew very definitely the day after. (I take mine at bed-time. So within 24 hours it was abundantly clear.)

But we are all different.

Bearfam profile image
Bearfam in reply to helvella

Maybe it depends how underactive we are. If that is even a phrase? As I was just outside of normal TSH when diagnosed so maybe have a bit of functionality. But maybe someone who would have very high levels without meds feels the lack of med more profoundly? Also I'm so used to feeling sluggish I'm not sure I totally notice it for what it is. And low mood with everything that's happening in the world felt expected! It's certainly been a wake up to remember the meds but also pay attention to how feeling if I forget them. Thanks for your reply

I used to notice that if i forgot one a.m. dose, it invariably led to me forgetting the next days too, due to not being 'with it' the next morning.

Sometimes i would 'crash' mentally and physically at about 2 pm on the day i forgot. Eventually i learned to think 'did i take it this morning?' whenever i felt my brain going to sleep in the afternoons.

I only take Levo, so there is no logical reason for this to happen ,( as T4 lasts much longer than that in the blood). But it happens anyway in my case.

I've been on Levo for 17 yrs , so i am confident this is actually happening to me and not just'in my head'. But i have no scientific explanation for how it could be happening.

Bearfam profile image
Bearfam in reply to tattybogle

That's interesting I'm on once a day. Makes me feel less terrible about forgetting.

I went off levo for a few days once to see if it might be causing some other symptoms. I think within about 24-48 hours, I started to feel depleted but didn't make the connection immediately. Within, I don't know 3 or 4 days, I was really bad off -- exhausted, stressed, brain wouldn't work -- and finally realized it was because I was off levo. It was awful.

Thanks for the replies. I have a pill dispenser for my other medication which I take on an evening so it is not at the same time as the levothyroxine. I thought I could remember on pill on a morning but obviously not! So will be getting another one for AM. I don't think I didn't take it all in this period but only a few doses. I would take my pm meds and think oh I forgot the levothyroxine this morning then do the same thing!

Really interesting that people say missing doses does have an impact. I'm over due a review but with covid it's not essential to go into the GP surgery for a blood test. So I'm happy to wait. I think maybe my dose should be higher anyway so it's not like my dose fully removes all symptoms so I'm always a bit tired and this period was just a bit worse than normal. Rather than feeling great then feeling terrible, if you know what I mean?

It's so lovely to be able to get a bit of advice form people with similar experiences. Thanks xx

I never miss my doses because I set my wrist watch alarms to remind me.

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