T4 conversion

[fiftyone]

It seems that when my T4 (levo) converts to T3, the T3 is occasionally above the lab range. I don't take T3, so it is entirely a natural process and I thought the body converted whatever amount of T3 it needed. Is my body doing something wrong, or is the lab range inadequate?

[Zazbag]

Do you mean that you have really high conversion of T4 to T3?

[fiftyone in reply to Zazbag]

must be. All I know is that my T3 is generally high and apparently above the range on occasion.

[Zazbag in reply to fiftyone]

Well it sounds like you are a very lucky person! If you have Hashimoto's maybe you're having a transient hyper phase...

[fiftyone in reply to Zazbag]

i have no idea if i have hashimotos. Just underactive thyroid as far as I've known for the past 35 years

[Zazbag in reply to fiftyone]

Ah in that case you probably aren't having a hyper phase as you've been underactive for so long. Do you feel good? What are your latest blood test results?

[fiftyone in reply to Zazbag]

metabolically, very well indeed. My TSH is 0.0005, my T4 is about 5 points above lab range and my T3 is high but, at present, within range. Sometimes, as I say, it goes above range. no overdosing symptoms whatever. Sleep well, calm etc.

[SlowDragon Administrator in reply to fiftyone]

If TPO or TG thyroid antibodies are high this is usually due to Hashimoto’s (more commonly known in UK as autoimmune thyroid disease).

About 90% of all primary hypothyroidism in Uk is due to Hashimoto’s.

Suggest you look through all your historic test results, see if/when thyroid antibodies were tested

If hypothyroidism started after hormonal changes (pregnancy, menopause, etc) then likely cause is autoimmune

Low vitamin levels are particularly common with Hashimoto’s. Gluten intolerance is often a hidden issue to.

Link about thyroid blood tests

thyroiduk.org/getting-a-dia...

Link about Hashimoto’s

thyroiduk.org/hypothyroid-b...

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

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)

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

thyroiduk.org/getting-a-dia...

Medichecks Thyroid plus antibodies and vitamins

medichecks.com/products/adv...

Thriva Thyroid plus antibodies and vitamins By DIY fingerpick test

thriva.co/tests/thyroid-test

Thriva also offer just vitamin testing

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

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...

monitormyhealth.org.uk/thyr...

Low vitamin levels get more common as we age

Important to test annually

[DippyDame]

How much Levo are you taking?You say below that your FT4 is sitting just above range with your FT3 just below range.

Are you perhaps taking too much Levo?

Your TSH is low because your pituitary gland recognises the high level of hormones in your body so does not respond by signalling (TSH is the messenger!) the thyroid gland to produce more. That is as expected.

Conversely, too little hormone = high TSH.

For good health TSH should be 1 or even slightly lower.

Your TSH is on the low side which indicates too much exogenous hormone.

Clearly your conversion is good which is important.

Thyroid hormone levels vary throughout the day, I'm assuming you followed pre- test protocol as advised on the forum.

For good health FT4 and FT3 should sit close to 75% through their respective lab ranges

Suggest you have antibodies tested to detect or eliminate Hashimoto's

Otherwise, unlikely lab results wrong....maybe you need to adjust your dose

Also, you are legally entitled to request copies, from your surgery, of any lab results they hold in your file.

Post any labs you have including ref ranges then members will be able to advise in more detail. SlowDragon has given you all the info you need in order to do that.

[fiftyone in reply to DippyDame]

no matter what the figures say, I feel very well. If I reduce T4 by just a smidgeon, I become very tired, experience tinnitus. I wonder why the figures don't reflect how I feel. According to the figures I should be hyper. I'm nothing like that, even put on 5lbs in weight in past six months.

[DippyDame in reply to fiftyone]

You didn't say how much Levo you are taking

Are you also taking T3?

If you feel well then fine....people were treated by clinical evaluation long before thyroid function tests.We are all different and our needs vary, some people do need to have results very slightly out of range to feel well.

Diagnosing by box ticking numbers isn't always ideal. Medics rely far too much on their computer screens and forget they are dealing with human beings not mechanical robots. I feel a soapbox moment coming on!!

I have a form of thyroid hormone resistance and I need my FT3 to be well above range so that it overcomes the resistance and gets the T3 into my tissues.....long story but not particularly relevant here! Just an example.

If you are hypo you cannot physically become hyper - what symptoms could indicate is overmedication, which is a different matter

You say you have no symptoms and feel very well, then that is the aim. You know your body better than anyone else....do what you are already doing, listen to it!

Any concerns ...then feel free to ask more questions.

Stay well and safe...

[fiftyone in reply to DippyDame]

thanks for the info. Interesting about needing T3 because of resistance. My T4 is way above lab range and I don't take T3. Doctors are always telling me to cut down on Levo without examining me, just looking at computer screens and figures. Seems to me, reading here, that people react to differently to medication.

[jimh111 in reply to fiftyone]

I suspect you need high fT4 to generate sufficient T3. Since you are on levo only you need extra T4 to get enough T3 but as fT4 goes high TSH falls and T4 to T3 conversion rate lowers. You also produce extra reverse T3 which inhibits T4 to T3 conversion in organs such as the brain.

Sorry about the complexity, in short if you were given some liothyronine I suspect you would be better with more moderate hormone levels. As fT4 goes high the body fights against it so you end up with abnormal hormone levels. If doctors prescribed some liothyronine I'm sure patients would get better with lower overall hormone levels.

[fiftyone in reply to jimh111]

I asked an endo the other day about the possibility of reducing T4 but supplementing with T3 if necessary. He told me he couldn't prescribe T3 cos it is 'blacklisted'. My GP confirmed that this was indeed the case.

[jimh111 in reply to fiftyone]

You need to find the CCG that controls your local NHS and get hold of the document that 'blacklists' liothyronine. A doctor can prescribe, they can override the CCG but I can understand their reluctance to do so. If the CCG does blacklist liothyronine I would complain to NHS England (copy to CCG) and say that levothyroxine only is putting your health at risk.

[fiftyone in reply to jimh111]

thank you for that info. I will look into it.

[DippyDame in reply to fiftyone]

If as jimh111 suggests your body is producing more T4 to get enough T3... eventually this will cause problems as he explained.However, your FT3 result is close to top of range so it doesn't look as if your body is struggling to produce an adequate level of T3. You say you feel well so an adequate amount of T3 must be reaching the tissues suggesting there is no resistance RTH) involved.

But, without having the detail of current labs for full thyroid panel and without knowing how much levo you are taking we cannot be more precise.

Never heard of T3 being "blacklisted"....sounds like an excuse to avoid prescribing because it is expensive and difficult to monitor. Using T3 is not an easy option, it needs to be understood and respected.......it's not an quick fix like picking a bottle of paracetamol, off the shelf and swallowing a couple of pills. It's hard work! And I speak as someone who needs a high dose of T3- only to function....it took over 2 years to work out what my body needs and that was after becoming increasing ill over about 50 years ( 20 on levo) and eventually barely able to function!

Since you say above that you feel "very well" why do you want to add T3 when your labs are already close to the top of the range. Unless you have RTH you need to keep your FT3 within or very close to the top of lab range.....adding more would likely cause you to overdose. You could try adding a little T3 but you would need to drop your levo.....difficult to say without more info.

As suggested earlier you need to test antibodies, Hashi's may be affecting hormone levels.

Since you are well and if your levo dose isn't high I would stick with the status quo but test again in 8 weeks for reassurance....meantime note any changes in symptoms and listen to your body!

As I said I'm not a medic....just a few thoughts!

Best...

DD

[fiftyone in reply to DippyDame]

thanks for the info