Subclinical hypothyroid.: Just a quick question... - Thyroid UK

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Subclinical hypothyroid.

Dan5795 profile image

Just a quick question, does hypothyroid affect your blood sugars and testosterone levels?

36 Replies
SlowDragon profile image

Yes can do

How much levothyroxine are you currently taking

Looking at previous posts you were only on 25mcg levothyroxine and results showing that you needed dose increase to 50mcg

Bloods should be retested 6-8 weeks after increasing levothyroxine to 50mcg

Important to retest vitamin D, folate, ferritin and B12 at least annually

Nothing on your profile

Are you male or female?

High HBa1c linked to being hypothyroid

High cholesterol levels linked to being hypothyroid

Poor kidney function (low GFR) linked to being hypothyroid

All are reversible when on correct dose levothyroxine

Dan5795 profile image
Dan5795 in reply to SlowDragon

The doctor told me he wouldn't increase my dose because my numbers on paper looked good. But l still feel drained .

SlowDragon profile image
SlowDragonAdministrator in reply to Dan5795

Good grief …GP is clueless

See different GP at surgery

Levothyroxine doesn’t “top up” failing thyroid

It replaces it

Standard starter dose of levothyroxine is 50mcg

Dose is increased slowly upwards in 25mcg steps over 6-9 months until TSH is around or under one and all symptoms resolved

You need to take control and be assertive

Print out all guidelines

INSIST on 25mcg dose increase in levothyroxine

Bloods should be retested 6-8 weeks later

Request that B12, folate, ferritin and Vitamin D are tested NOW

Approx how much do you weigh in kilo

guidelines on dose levothyroxine by weight

Even if we frequently don’t start on full replacement dose, most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until eventually on, or near full replacement dose

NICE guidelines on full replacement dose


Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.

Also here

Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months. RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.

For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.

For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).

If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.

BMJ also clear on dose required

TSH should be under 2 as an absolute maximum when on levothyroxine

Replacement therapy with levothyroxine should be initiated in all patients to achieve a TSH level of 0.5-2.0pmol/L.

NHS England Liothyronine guidelines July 2019 clearly state on page 13 that TSH should be between 0.4-1.5 when OPTIMALLY treated with just Levothyroxine

Note that it says test should be in morning BEFORE taking levothyroxine

Also to test vitamin D, folate, B12 and ferritin

Graph showing median TSH in healthy population is 1-1.5

Aim is to bring a TSH under 2.5

UK guidance suggests aiming for a TSH of 0.5–2.5

Persevere - have all guidelines printed and be ready to quote them

Bearo profile image
Bearo in reply to SlowDragon

The link above starting has a very useful bit near the end of the document - part 4 - where it says that FT4 and FT3 should be part of regular testing to avoid over or under medicating. A little further down it states the importance of the patient agreeing with the treatment plan.

Sorry, l am male.

SlowDragon profile image
SlowDragonAdministrator in reply to Dan5795

Presumably you have had low testosterone results?

SlowDragon profile image

High HBa1c

Should normalise as dose levothyroxine is increased

Dan5795 profile image
Dan5795 in reply to SlowDragon

Thanks for the information, maybe changing doctors is the way forward in my situation.

SlowDragon profile image
SlowDragonAdministrator in reply to Dan5795

Try different GP within the surgery initially

Take printed copies of guidelines with you…or have them ready to quote if it’s a phone consultation

Email Thyroid U.K. for list of recommended thyroid specialist endocrinologist and doctors

Meanwhile get vitamin D, folate, ferritin and B12 levels and thyroid antibodies tested

Test early Monday or Tuesday morning, before 9am and last dose levothyroxine 24 hours before test

List of private testing options and money off codes

Medichecks Thyroid plus antibodies and vitamins

Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins by DIY fingerprick test

About 90% of primary hypothyroidism is autoimmune

Is there autoimmune disease in your family

Ukie profile image
Ukie in reply to Dan5795

Hi Dan. Try to find out if any of the GPs at your surgery have a specialism; if they have an online service it may be there. If none of them have a specialism that seems helpful, see if any specialise in women’s problems. I know you’re a man, but far more women are affected by this condition, and in my experience they tend to know more about it. Good luck.

Dan5795 profile image
Dan5795 in reply to Ukie

Thanks for the advice l will do some research, my GP has referred me to an endo because it seems this problem is affecting my hormones.

Thanks for the link.

Do you have high cholesterol? If so, are you taking statins?

Yes l have high cholesterol but no statins.

greygoose profile image
greygoose in reply to Dan5795

Only just seen this by accident, because you didn't click on the blue 'Reply' button under my question.

OK, so the high cholesterol is saying that you are under-medicated. Try reminding your doctor that measuring cholesterol used to be a why of diagnosing hypothyroisim, because it is caused by low T3. So, if your cholesterol is still high, it's because your FT3 is low, i.e. you're still hypo.

I asked about the statins because if you were taking them, it could be the cause of your low testosterone. Testosterone is made by the adrenals using cholesterol. But, of course, if the cholesterol is not reaching its destinations, but building up in the blood, due to low T3, then that probably would affect your testosterone level. But, any way you look at it, you need an increase in dose - probably several - and your doctor is ignorant!

Dan5795 profile image
Dan5795 in reply to greygoose

You might be right on that one, l am under medicated because l feel weaker than before taking Levo.

greygoose profile image
greygoose in reply to Dan5795

Well, you would be under-medicated on only 25 mcg levo! That's a given. It's not even a starter dose for a little old lady. And, what happens is this:

* you are hypo which means that you have high TSH and low FT4 and FT3.

* this means that your thyroid needs abnormal levels of TSH to stimulate it to make sub-normal amounts of T4 and T3.

* you start taking exogenous thyroid hormone, the pituitary senses this and reduces the amount of TSH it produces.

* the drop in TSH means that the thyroid can no-longer make the small amount of hormone it was making, and T4/3 levels drop.

* if you're only taking 25 mcg, that is not enough to compensate for the amount of hormone the thyroid has stopped making.

* you end up with less hormone in your system that you had before you started taking the levo.

This is the theory, anyway. I can't back it up without seeing your numbers before and after starting taking levo. :)

greygoose profile image
greygoose in reply to greygoose

In fact, it might be even worse than that! The thyroid makes T4 and T3. You are now only taking T4 (levo). You have lost the T3 (the active hormone) the thyroid was making. Plus, you no-longer have the conversion that was carried out within the thyroid.

If you are a poor converter, then your FT3 is going to be very low with all the sources of T3 that you have lost.

Dan5795 profile image
Dan5795 in reply to greygoose

These are my results since taking Levo.TSH.4.04 normal range 0.27-4.2

FREE T3 5.66 normal range 3.1-6.8

FREE THYROXINE 15.2 normal range 12-22

greygoose profile image
greygoose in reply to Dan5795

Well, you seem to convert ok, but that TSH is saying something isn't right.

Do you have your results from before you started levo?

Dan5795 profile image
Dan5795 in reply to greygoose

last year before Levo t4 12,6 normal range 7.0 -17.0TSH 4.65 normal range 0.20-4.50.

2012 when l first did thyroid test TSH 4.49 normal range 0.2-4.5

T4 13.1normal range 9-23 and l felt well in 2012.

greygoose profile image
greygoose in reply to Dan5795

OK, so...


TSH 4.49 (0.2-4.5)

T4 13.1 (9-23) 22.14%

and l felt well in 2012.

I can't imagine how, with those results. Your FT4 was very low, so possibly your FT3 was, too.

On the other hand, could be that your FT3 was reasonable because a dying gland often make more T3 than T4 in order to preserve levels. But, of course, that can't last.

2021, before Levo

TSH 4.65 (0.20-4.50)

t4 12,6 (7.0 -17.0) 56%

Well, your TSH is slightly over-range there, a bit higher than 2012. But your FT4 is a lot higher! I'm surprised you got diagnosed with those results - although there's no doubt that you are hypo.

How did you feel then?

This year, on 25 mcg levo.

TSH.4.04 (0.27-4.2)

FREE T3 5.66 (3.1-6.8) 69.19%

FREE THYROXINE 15.2 (12-22) 32%

So, these results are weird. Your TSH has only dropped slightly, which isn't surprising on only 25 mcg. Your FT4 has dropped. But, your FT3 is really good. Of course, it could be the high TSH driving conversion, and if you increase your dose and the TSH drops, your conversion could suffer. Time will tell.

So, your doctor refuses to increase the levo because 'everything is in-range'? lol The blockhead!

Two things doctors are really, really bad at:

1 all things hormonal - especially thyroid hormones - especially T3.

2 understanding and interpreting blood test results and ranges.

Just because a result is in-range, doesn't make it right for you. The ranges are too wide. They cannot be 'normal' all the way through, but he doesn't understand how ranges are arrived at. Have a look at this article, and you might be able to explain it too him:

The normal range: it is not normal and it is not a range

And, if we're talking 'normal' - euthyroid - a euthyroid TSH (i.e. in someone with no sort of thyroid problem) is around 1, never over 2, and you are hypo when it reaches 3. But, doctors don't know that. They think that any result that falls anywhere within the range has to be perfect. Nor do they understand that it's often not even good enough to get levels back to euthyroid, because someone who is hypo and taking thyroid hormone replacement, often needs their Frees higher than most euthyroid levels, and thus the TSH lower. Often below range. So, your TSH is much, much too high.

And, it looks like you've been hypo for a long time. And, the longer you're untreated/under-treated, the harder it is to find the right dose. So, something needs to be done, sooner rather than later. And, as so often happens with thyroid, the problem lies more with the doctor than with the disease!

However, I'm confident that when you do find the right dose, your testosterone will right itself.

Crikey. Got it. Why ‘normal’ with symptoms is not normal. This is just such good information. “Subclinical” pah!

dunestar profile image
dunestar in reply to greygoose

Great article on ranges. I think the majority of hard pressed GPs just look for anything red and that's it.

Dan5795 profile image
Dan5795 in reply to dunestar

Without forums like this only God knows what would be happening. Especially if you had a doctor like mine who told me to put away a note l had with my symptoms.

dunestar profile image
dunestar in reply to Dan5795

Goodness gracious! When I tried to engage my GP in conversation I was told I was far too analytical and trying to be a doctor!

Dan5795 profile image
Dan5795 in reply to dunestar

To be honest, sometimes l have asked myself why l even bother going to the doctors because my doctor is Mr google he knows everything.

greygoose profile image
greygoose in reply to Dan5795

That's why so many of us stop going to the doctor, and try to self-treat.

waveylines profile image
waveylines in reply to Dan5795

And thats why many doctors hate Dr Google! 😂

greygoose profile image
greygoose in reply to dunestar

I cannot take any credit for the article, it was helvella that found it. :)

I expect GPs do just look for anything red, but I don't think it has much to do with being hard pressed. They just don't know any better. But, what's even worse is that the technicians that do the tests know nothing, either! They don't even know the patient. It should be up to the doctor to interpret the results intelligently, but they just don't have that knowledge to be capable of doing that.

waveylines profile image
waveylines in reply to greygoose

I totally agree greygoose. Ive told the doctor whats wrong with me every time......these days they ask me as they know I will have looked into it before I speak to them......face to face is still gold dust.......that way they dont have to apply their fragile brain cells at all. Otherwise they just treat symptoms not causes. It annoys me greatly that they spend years training but still cant make intelligent diagnosis even of commonal garden sort. The best you get is fast tracking or referral elsewhere. Even worse recent encounters with the younger ones that have taken over dont even inderstand their core pharmacology.......I find them scary! Why specialist consultants hand management back care over to them I really dont know as they havent a clue.

SlowDragon profile image
SlowDragonAdministrator in reply to Dan5795

Was test done early morning and last dose levothyroxine 24 hours before test

FT4: 15.2 pmol/l (Range 12 - 22)

Ft4 only 32.00% through range

FT3: 5.66 pmol/l (Range 3.1 - 6.8)

Ft3 surprisingly good at 69.19%

Ft4 is the result that relates to how much levothyroxine you are taking

Most people when adequately treated on just levothyroxine will need Ft4 at least 60% through range….or higher

Dan5795 profile image
Dan5795 in reply to SlowDragon

Yes, the test was done in the morning.

SlowDragon profile image
SlowDragonAdministrator in reply to Dan5795 you have an underactive thyroid (hypothyroidism), treatment may be delayed until this problem is treated. This is because having an underactive thyroid can lead to an increased cholesterol level, and treating hypothyroidism may cause your cholesterol level to decrease, without the need for statins. Statins are also more likely to cause muscle damage in people with an underactive thyroid.

dunestar profile image
dunestar in reply to SlowDragon

Blimey, didn't know that about statins and hypothyroidism! I'm on statins with untreated "subclinical" hypothyroidism and my muscles feel achey!

I too would like a simple concise non-hyper-medical explanation. Everything is all interconnected, but when it gets explained the explanation seems to get deep in the weeds and many don't get much out of it !

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