Quick Question - Difference between T3 & T3L?.

[Mikico]

Hi,

Just received latest results - can you please help me understand the difference between T3 and T3L.

I am low on T3 0.8 (0.7 -2) but within ‘good’ range for T3L 3.00 pg/ml (1.58 - 3.91). Does this mean that am receiving enough T3? Apologies - am getting all confused, or am a poor converter?

Currently on 75mcg/daily Levo and taking all supplements to achieve optimal vitamin levels.

Improvements (last two months):

B12 : 367 (211 - 911) to 503 (187-883)

Ferritin: 10 (11 - 307) to 34 (11 - 307)

Folate: 2.8 (2.5 - 4.5) to 3.5 (2.5 - 4.5)

Apart from D which has dropped?

D: 60.8 (30 - 100) to 49.9 (30 - 100)

Thanks!

[helvella]

T3L is Free T3. (French L = libre = free)

T3 is Total T3.

(A result which doesn't say whether it is free or total does need to be checked as it could be either.)

Most T3 in our blood is bound to proteins, and only a tiny proportion is free. But it is the free portion which is readily available to be picked up and transported across cell membranes. The bound T3 effectively acts as a reservoir.

The units for Total T3 are usually 1000 times those used for Free T3 - e.g. nmol/L for Total and pmol/L for Free T3. This means that there is around 500 times as much bound T3 as Free.

To a very large extent, Total T3 is influenced by the amount of binding protein in your blood.

[Mikico in reply to helvella]

Ok - that makes sense. Thank you for clarifying - much appreciated.

[nellie237]

Libre = Free. Brain fog, hey. 🤪 What can you do?

I'll let somebody more experienced advise on results.

[Hidden]

Not many doctors test total Ts. I am not sure how to interpret them as I have never had mine tested nor read about how they should be interpreted. But your free T3 actually looks better than your free T4 which is low in range. You are not on T3, are you? Taking T3 would explain why your FT3 is higher than your FT4. But if you are on 75 mcg of levo, and no T3, it´s strange that your Ft4 is so much lower than your FT3...usually, when on levo only, it´s the other way around. It would be interesting if anyone could explain that!

[Mikico in reply to Hidden]

It’s all very odd. Am not taking any T3. Only difference is that am now taking supplements for the Fab Four (Folate, D, B12, Ferritin) Maybe the vitamins are starting to help with absorption as FT3 increased from 2.4 (2.1 - 4.4) in Nov to 3.00 (1.58 - 3.91) in Jan. Am seeing a naturopath next week to explore NDTs. Thanks for your reply.

[Hidden in reply to Mikico]

A follow-up question: I saw that you are in Spain. Can naturopaths actually prescribe NDTs such as Erfa or Armour in Spain? In most countries I know of, they cannot, so what they do is recommend thyroid glandulars (porcine or bovine) with no declared hormone content.

[Mikico in reply to Hidden]

That is good to know. My GP suggested I see a naturopath if I was interested in exploring NDTs. However, I will definitely keep that in mind. Given my recent results - may not need any extra T3.

[Hidden in reply to Mikico]

Judging by your free T3 levels, no. Poor converters have high FT4 and low FT3. Yours are the very opposite. So I agree it would be a good idea to increase levo instead. If it turns out later that you need T3, your doctor can prescribe liothyronine for you.I am a bit wary of naturopaths because many of them recommend iodine supplements to thyroid patients whether they need them or not.

Plus, NDT is very expensive.

[greygoose in reply to Mikico]

Maybe the vitamins are starting to help with absorption

Improving nutrient levels does not help with absorption at the gut level. Exogneous thyroid hormone goes through the gut wall into the blood.

It might be helping absorption at a cellular level, but you wouldn't see that on a blood test, because the blood test just tests what's in the blood.

Could be it's helped with conversion, but doubtful at this point, and that would not explain why your FT3 is higher through the range than the FT4. That is unusual.

So, given that you are converting well, why do you want NDT? Perhaps an increase in levo might be more appropriate.

[Mikico in reply to greygoose]

My thyroid is a complete mystery to me. Originally thought I needed extra T3 but my recent results indicate otherwise. Think you’re right - NDTs may not be for me - will look to increase Levo. Thanks again

[greygoose in reply to Mikico]

You're welcome.

NDT is very difficult to come by, these days, so if you can do without it, all the better!

[radd in reply to Mikico]

Mikico

'Maybe the vitamins are starting to help with absorption'

Absolutely, normal thyroid synthesis & metabolism is dependent upon essential trace elements, ie iodine, iron, selenium, zinc, etc and supplementing deficiencies can make a huge difference to thyroid gland & hormone function. Just think of iodine in the extreme, and how selenium has been shown to reduce thyroid nodules and TPOAb's.

Both thyroid hormones & iron are directly influential on our metabolic rate. Iron is an important component of thyroid peroxidase but seeings as many of us don’t have a thyroid gland it is still important for influence of RBC production which together with VitB12 & folate will encourage better gut function/absorption which will extend to our meds.

There are also studies showing iron levels to influence hypothalamic secretion of THR, and deficiencies to increase hepatic RT3 deiodination. I also read iron is required for T3 uptake at receptor level.

Vitamin D is associated with an up-regulated D2 (deiodinase enzyme) that increases peripheral conversion of T4 -T3 (liver, kidney, etc), and for those of us with Hashi (not you) it helps positively modulate the immune system, reducing destructive inflammation that impairs good conversion.

There are many further examples of why your FT3 has improved through supplementing nutrient deficiencies and I experienced exactly the same after optimising my own previous unknown & long term deficiencies.

Hence, we often say when members keep missing their thyroid meds sweet-spot to try optimising iron and nutrients alongside meds as this will improve meds effectiveness.

I like your euphemism 'Fab Four.' I think it should become regular forum vocab 😊.

[Mikico in reply to radd]

Thank you - really interesting read!

I think for me, essentially, as my iron levels (ferritin) were so low it was affecting absorption in some way. So it's interesting to read that iron 'is required for T3 uptake at receptor levels.'

P.s. Very happy for 'Fab Four' to be adopted as forum vocab 😀

[Poniesrfun]

Numbers all well and good but how well are you functioning and feeling at your current levels? I tend to be a fan of "if it works, don't fix it".

Patti in AZ

[Mikico in reply to Poniesrfun]

Hi - am feeling better but still not 100%. The increase in my FT3 has improved my overall energy. However, now need to get to the bottom of why my FT4 is low. Will start experimenting with raising my Levo to 100mcg/daily and continue with the Fab Four supplements. 😉