Starter dose made no difference!: I have taken a... - Thyroid UK

Thyroid UK
110,080 members127,944 posts

Starter dose made no difference!


I have taken a peek at my blood test results online (can't get Dr appt to discuss 'til 9th Jan). They seem to imply that my starter dose of 25mcg Levothyroxine has made no (or barely any) difference. Is this normal? Is it just a slow process of upping the dose 'til it starts to improve? Seems like it's going to take forever to feel better at this rate! Here's my history to give a better picture:

14 Apr TSH 8.4 (0.27 - 4.2) antibodies 96 (<34)

25 Aug TSH 5.8 antibodies 106

16 Sep TSH 5.6 antibodies 106

16 Dec TSH 5 (this one is 3 months after starting on Levo)

n.b. these results were all taken after food, and the last one I did take my Levo as usual, as I can't get early morning appointments (I know some people recommend early morn, no food or meds, but I believe it doesn't make much of a diff to TSH results, and Dr didn't test FT4).

I also noted an abnormal result next to full blood count (mean cell haemoglobin concentration 32.8 (33.5 - 37). Does that mean I'm anaemic too?!

Interested to get opinions before I go speak to the Dr. Thanks!

18 Replies

A few comments :

1) Your starting dose of Levo was very small. Unless you have major heart problems or are elderly then you should have started on a dose of 50mcg.

2) Blood tests should be done every 6 weeks, not every 3 months. After each blood test, dose should be raised by 25mcg Levo until symptoms have gone and blood tests are okay. As you say, the process is slow enough as it is without doubling the time between blood tests.

Blood tests are recommended to be done early and while fasting for several reasons.

a) Doctors use TSH (a pituitary hormone) to determine dose rather than measuring thyroid hormones directly. This leaves many people under-medicated and continuing to suffer symptoms. So getting the highest possible TSH in your blood tests is in your best interests.

b) TSH levels have a circadian rhythm with levels being highest in the middle of the night and being lowest in the middle of the afternoon. To get the highest levels possible during surgery hours it is best to get blood taken as early as possible.

Look at the graphs on page 2 :

c) There have been claims that TSH is lowered by eating, so getting tested while fasting is often recommended. From my personal point of view the evidence I've seen for this is extremely poor. I do fast for blood tests however, but not because of any suggested effect on TSH. I fast because it maximises the comparability of my test results from one test to the next.

d) It is also recommended that Levo should not be taken for 24 hours before testing. Some doctors/labs, under some circumstances, will test Free T4 as well as TSH. To stop Free T4 from being really high (and thus increasing the chance of a reduction in dose), Levo must not be taken too close to taking a blood sample. As I understand it, after 24 hours Levo will have been metabolised enough for it not to be swishing about in your blood stream in large amounts and will have entered the peripheral tissues. And let's face it, that is where it does its main job, it doesn't do a lot in your blood stream.

greygoose in reply to humanbean

I think we have seen proof on here, of the differences between fasting and non-fasting TSH results. I do believe it makes a difference.

humanbean in reply to greygoose

The paper I've seen quoted that claims fasting gives a higher TSH is this one :

Do you know how they proved that TSH is higher when fasting?

They took blood samples between 7.30am and 8.30am on patients who had fasted overnight. Then they gave them breakfast and measured their TSH again between 10.30am and 11.00am. And lo and behold the patients' TSH had dropped. The researchers attributed this drop in TSH to eating. But it is already known that TSH alters with time of day, and in fact reduces as the day goes on. The eating may have had nothing to do with the results they got.

This is basically a problem known as confounding. The testing methods they used can't separate out the effects of time of day and food intake, so their research is not worth the paper it is written on, sadly, and they haven't proved anything.

This is why I say I don't believe the evidence that fasting has an effect on TSH. It may do. But it hasn't been proven with the paper above.

If there are any other papers that I've missed on this subject I'd be happy to read them.

greygoose in reply to humanbean

No, I wasn't talking about scientific proof, I haven't actually read any papers. I was talking about practical experience of the people on here. When they give their TSH results, and say whether they fasted or not - and we do have some people that have two tests quite close together, for whatever reason - one just gets the impression that their TSH is lower when they haven't fasted. Nothing scientific about it, I'm afraid, just the way it seems to be.

humanbean in reply to greygoose

Oh, okay, I got the wrong end of the stick there, sorry. :)

greygoose in reply to humanbean

No problem. :)

Clutter in reply to humanbean

Humanbean and greygoose,

Research showing TSH drops post prandially:

humanbean in reply to Clutter

The first link you give is to the paper that I criticized earlier. It was poorly designed and therefore can't determine whether the differences they found were due to time of day or fasting state.

That first link refers to three references (numbered 11, 12 and 13 in the paper) on the same subject :

Serum TSH variability in normal individuals: the influence of time of sample collection.

The above research seems to have been performed in the same way as the first link, although the detail is not really there to be sure. It actually makes life harder for patients by suggesting :

the diagnosis of subclinical hypothyroidism should not be made only on a fasting TSH measurement

Reference number 12 :

Influence of meal composition on the postprandial response of the pituitary-thyroid axis.

doesn't even mention time of day as being a factor although from the wording of the abstract it was clear they were doing blood tests at different times of day. So again I wouldn't take it as true in its conclusions about food.

Reference number 13 :

Fasting or Random: Which venous blood sample is better for Thyroid function testing?

is actually the best link of all.

It has the following two statements :

TSH was lower in the post-cibal (11:00am) compared to those of fasting (09:00am) samples. No difference was found in the T4, fT4, T3 and fT3levels, in the fasting and post-cibal states.

So this just duplicates the research in the other links without considering time of day might be the relevant factor rather than food. But then... Hallelujah! ... they do their blood testing at the same time of day, both fasted and non-fasted in the same patients :

There was no difference in the fasting and post-cibal TSH levels in the same individual, when samples are taken at the same time of the day (09:00am), within a span of 7days.

So, this is the first time that a test is done suggesting that the important factor is time of day, not the fasting or non-fasting state.

The full paper for this final reference is freely available :

MandShef in reply to humanbean

Wow, thank you, this is useful info. I actually only mentioned I'd eaten and taken my Levo as a disclaimer that my test may not have been done under what might be considered 'ideal' conditions. Early morning appointments are just not practical for me, as I'm busy doing the school run etc. At least based on the info you've found, if I just aim to be consistent with the time I should be OK. Seeing as I can't do much about the fact I've got kids to look after in the mornings, this'll do me for now!

Stemar in reply to humanbean

That's interesting because my last 2 blood test have been done fasting, one at 8am when my TSH came back 5.8 (october) the following test at 12 noon ,still fasting (had a scan appointment so did my bloods after that ) and that came back at 1.13 so based on that he said my thyroid was normal, currently on 125 Levothyroxine

humanbean in reply to Stemar

Stemar, try and arrange blood tests for 9am or earlier (preferably earlier), and try to be as consistent as you can from one test to another.

I know this is so much easier to say than to do, but people just have to do the best they can, keep their fingers crossed, and hope for the best. There really isn't much else we can do.

Stemar in reply to humanbean

Thanks normally there for 8am but with the scan due at 9.30 I couldn't be sure I would be out of having bloods done in time

Regarding your low MCHC :

Mean corpuscular haemoglobin concentration (MCHC) is a calculation of the concentration of haemoglobin inside the RBCs. Decreased MCHC values (hypochromia) are seen in conditions where the haemoglobin is abnormally diluted inside the red cells, such as in iron deficiency anaemia, long standing inflammation or thalassaemia

Above quote is from

You should ask your doctor to do a full iron panel. You never know, they may actually agree. Get a copy of your results, post them in a new post, and ask for feedback.

Thanks all for taking the time to reply. As I've mentioned in a reply earlier, my stating I had eaten & taken Levo was really just a disclaimer to acknowledge the tests hadn't been done under 'ideal' conditions! I can't do early morning appointments because I'm doing the school run. However, my main focus was to find out whether it's normal to have no response when starting out on Levo? I'm aware I've been started on a very small dose. I actually did feel a bit better initially, more energy, less brain fog. Then I caught a cold and the familiar zombie tiredness & brain fog returned, and whilst the cold went away, the other symptoms stayed! So I don't know whether I've had an initial response to the Levo, but then my body's slumped, or if I'm not responding, or if it's just too small a dose to expect results. Not sure what's normal when starting out. Thanks all (& here's to a healthy, happy new year!!).


Initial improvement on small starter dose, followed by slump is common response.

We have to introduce/increase Levo slowly to give our body time to get use to it. Once it has acclimatised, if TSH remains high /symptoms remain then the dose needs increasing. (25mcg steps max)

Testing 6-8 weeks after each dose change. Ideally early am.


Did your GP explain Levo should always be taken on an empty stomach and then nothing apart from water for at least an hour after. Many take on waking, but many of us prefer to take at bedtime. Can be easier/more convenient. There is research that shows taking at bedtime may also be more effective. (Can be equivalent to small increase in dose)

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 quality of life to occur."

MandShef in reply to SlowDragon

Nope! Luckily I found this forum, and now take it in the early hours when I go to the bathroom (4 - 6:30am). That way it's on an empty stomach, but I still get to eat breakfast at 7:30am. I think it's shocking that Drs don't explain this ...

You may also like...