Hi everyone, I’ve recently ordered a blood test to check my TSH, T4 and T3 levels.
I’m also having my antibodies, ferritin, vit D, B12 and folate checked aswell.
I’m fine interpreting the results of the vitamins and minerals, and I also understand that the higher the TSH the more underactive you are, and the lower the number, the more overactive you are, ideally TSH needs to be between 1 and 2….. I will be having the blood test before 10am, before food, drink and medication also…… my question is does my TSH levels need to be between 1 and 2 even if I’m getting the test done before 10am, since I know TSH levels get lower throughout the day??
Also how does T4 and T3 levels work?? Where in the range do they need to be??….
Does T4 need to be a high or lower number??
And does T3 need to be a high or lower number, or in the middle??
(I’m currently on 100 mcg levothyroxine, and my TSH has been between 2.05 and 2.50 for the last 6 month, but these tests where done around 12:00 after eating food, drink and medication) only recently learnt your not meant to do that with no help from doctor 😕
Thank you for your help in advance.
Written by
MarvelDC
To view profiles and participate in discussions please or .
I also understand that the higher the TSH the more underactive you are, and the lower the number, the more overactive you are, ideally TSH needs to be between 1 and 2…..
We-ell... maybe. But it's not always that simple. In fact, the TSH is a very bad indicator of thyroid status - especially once you're on thyroid hormone replacement. And, even before being on thyroid hormone replacement your TSH can be low but your thyroid hormone levels also low. So, you cannot draw any conclusions by just looking at the TSH - although doctors think you can.
A euthyroid TSH - i.e. in someone with no thyroid problems - will be around 1, never over 2. In someone who is hypo, the theory is that the lower the thyroid hormone levels, the higher the TSH. But, it's not the TSH itself that makes you hypo. It is the gland being unable to respond to the stimulus of the TSH.
And, once on thyroid hormone replacement, most hypos feel better when the TSH is 1 or under, or even suppressed. We usually need it lower than euthyroid because we need our thyroid hormone levels higher.
my question is does my TSH levels need to be between 1 and 2 even if I’m getting the test done before 10am, since I know TSH levels get lower throughout the day??
Pretty certain it's impossible to answer that question. Because when we're talking about the TSH, we're talking about the TSH before 9 am. I'm not sure it's possible to guess by how much the TSH will drop between 9 and 10. But, in any case, who said it has to be between 1 and 2? It doesn't. Why would it? If I were you, I'd forget about the TSH and concentrate on the actual thyroid hormones, T4 and T3. TSH is only important to doctors who know nothing about thyroid (gross over-generalisation but suits our purpose for this question).
Also how does T4 and T3 levels work?? Where in the range do they need to be??….
T4 and T3 levels are not so much affected by the time of day. Slightly, but not enough to bother about. They will be affected by the length of time between your last doses of T4/T3 and the blood draw.
As to where they need to be, they need to be where you need them to feel well. Optimal is not a number, it's how you feel. Most hypos feel best when they are around 75% through the range. But you may not be like most hypos. You, as an individual, may need them higher, or you may need them lower. So, let's just say, as a general rule, they should be at least over mid-range. Both of them.
(I’m currently on 100 mcg levothyroxine, and my TSH has been between 2.05 and 2.50 for the last 6 month, but these tests where done around 12:00 after eating food, drink and medication)
If your TSH is over 2 at midday, on 100 mcg levo, then 100 mcg levo is not enough for you.
FYI taking your thyroid hormone before the test does not affect the TSH.
hey grey goose, thanks for your reply, I appreciate that…. You mentioned that the T4 and T3 should be 75% through the range, does this relate to the higher numbers or low numbers in the scale…. Since I know having a lower TSH number is normally a good sign, but I don’t know if this also applies to T4 and T3 levels….
Also based on my current levels would you suggest I increase my medication by 12.5mcg just to begin with.
And I normally take my medication in the morning between 7am and 10am on its own without food, caffeine or other medications.
I had my iron and vitamin D levels checked recently, and they were in normal range but on the lower end, so I’ve started taking vitamin D and iron recently, I also found out I was deficient in b12 four month ago, so I’ve been having one injection a month, so my b12 levels are high now.
It’s been mentioned that T4 and T3 should be around 75% through the range, does this relate to the higher numbers or low numbers in the scale…. Since I know having a lower TSH number is normally a good sign, but I don’t know if this also applies to T4 and T3 levels….
It’s been mentioned that T4 and T3 should be around 75% through the range,
Every person is different as to where in range they might feel best
But many people find they need Ft3 at least 60-70% through range
Remember to test with correct timings
test early morning, ideally just before 9am, only drink water between waking and test and last dose levothyroxine 24 hours before test
as you have been improving B12 with B12 injections it’s recommended also to supplement a good quality daily vitamin B complex, one with folate in (not folic acid) may be beneficial.
This can help keep all B vitamins in balance and will help improve B12 levels too
But don’t start now because ......If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 7 days before ALL BLOOD TESTS , as biotin can falsely affect test results
In week before blood test, when you stop vitamin B complex, you might want to consider taking a separate folate supplement (eg Jarrow methyl folate 400mcg)
Post discussing how biotin can affect test results
Thanks Slow Dragon, I appreciate the help, I understand its better for the T4 and T3 to be 75% through the range, but should it be more towards the higher numbers or lower numbers??….. since I know the lower numbers are considered better for TSH.
Also am I able to take two different brands of levothyroxine to make up my dose?? Or is this not recommended
Also am I able to take two different brands of levothyroxine to make up my dose?? Or is this not recommended
Generally only change one thing at a time
So if increasing dose, initially don’t add a different brand
Once settled on higher dose then you could experiment
Some people notice no difference between any brands
Some people can only tolerate one brand or might need lactose free brand
We are all different
Most easily available (and often most easily tolerated) are Mercury Pharma or Accord
Mercury Pharma make 25mcg, 50mcg and 100mcg tablets
Mercury Pharma also boxed as Eltroxin. Both often listed by company name on pharmacy database - Advanz
Accord only make 50mcg and 100mcg tablets. Accord is also boxed as Almus via Boots,
Wockhardt is very well tolerated, but only available in 25mcg tablets. Some people remain on Wockhardt, taking their daily dose as a number of tablets
Lactose free brands - currently Teva or Vencamil only
Teva makes 25mcg, 50mcg, 75mcg and 100mcg
Many patients do NOT get on well with Teva brand of Levothyroxine.
Teva is lactose free.But Teva contains mannitol as a filler instead of lactose, which seems to be possible cause of problems. Mannitol seems to upset many people, it changes gut biome
Teva is the only brand that makes 75mcg tablet.
So if avoiding Teva for 75mcg dose ask for 25mcg to add to 50mcg or just extra 50mcg tablets to cut in half
But for some people (usually if lactose intolerant, Teva is by far the best option)
Aristo (currently 100mcg only) is lactose free and mannitol free.
You mentioned that the T4 and T3 should be 75% through the range, does this relate to the higher numbers or low numbers in the scale….
No, I didn't say 'should'. I said that's where most hypos feel well, but you might be different. It's the higher numbers.
Since I know having a lower TSH number is normally a good sign, but I don’t know if this also applies to T4 and T3 levels….
They have an inverse relationship. The higher the TSH, the lower the thyroid hormone numbers usually are. And vice versa. But, honestly, if I were you, I would forget about the TSH. Once it gets below 1, it's a very bad indicator of thyroid status.
Also based on my current levels would you suggest I increase my medication by 12.5mcg just to begin with.
Probably not. I'd probably say go with 25 mcg. But, I'd have to see the FT4/3 first, you've only given us the TSH. And dosing by the TSH is wrong.
Thanks Grey goose, that’s great… I’ll be having my bloods done Monday, so I should hopefully have the results back by Thursday, so I’ll put them up for further help if that’s ok, I’ve asked my doctor multiple times to do my T4 and T3, but they never do it, my old doctors did…. But not this one for some reason 😕
You said you have some confusion over where the frees should be on the scale. For FT3 and FT4 the scale starts with a low number going up to a high number. So when talking about over 50% through the scale we are looking for the numbers to be over mid way going towards the upper limit of the scale without being too high for the individual.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Help Interpreting Results 
Help interpreting results
Help interpreting thyroid results
Help with interpreting my results!
Blood results interpretation required
