T4 dropping on NDT but T3 not... Any advice?

[rosael56]

Hi everyone. I've been on Armour thyroid 2 grains since March. I did a blood test two days ago because I have an appointment with my thyroid doctor in a couple of weeks to see how things are going.

In July my results were:

TSH 0.007

T4 13.7 (12-22)

T3 6.3 (3.1-6.8)

My recent ones were:

TSH 0.008

T4 12.2 (12-22)

T3 6 (3.1-6.8)

Obviously I will discuss this with my doctor, but anyone have any ideas why this might be happening? I know a lower T4 is normal on NDT but I'm concerned mine is dropping almost out of range, while T3 is staying fairly stable. I've been feeling rough lately (very dizzy, migraines, joint pain). However I do also have POTS so it can be hard to know where symptoms are coming from. I also recently started the mini pill which may be contributing. And I take meds for my POTS, unsure if they'd have any effect but I don't expect many people here to have a lot of experience with them (Ivabradine and Fludrocortisone)

My vitamin levels are looking ok:

Vit D- 92

Ferretin- 48 (this is increased from 35 in July, working on getting it higher)

Total B12- 450 (am supplementing)

Active B12- 117

Just wondering if anyone has any experience with this? I'm wondering if I need to add Levo to my Armour.

[RedApple Administrator]

' I know a lower T4 is normal on NDT but I'm concerned mine is dropping almost out of range, while T3 is staying fairly stable. '

This seems to be typical for many people on NDT, regardless of brand. And is why some people find they need to add a low dose (e.g. 25mcg) of levothyroxine as well, to lift the FT4 level.

[rosael56 in reply to RedApple]

Ah interesting, I have seen some people add Levo to NDT. Maybe that's what I need. It's confusing to me why lower T4 would affect me if T3 is high, as I know T4 is just the storage hormone.. but I guess it can have an affect on symptoms?

[RedApple Administrator in reply to rosael56]

'T4 is just the storage hormone.. '

I don't claim to understand it fully, but it seems that, even if it is just a 'storage' hormone (some people say it's not that simple), a little T4 in the cupboard helps many on NDT to feel better.

[helvella Administrator in reply to RedApple]

I'm sure you understand more than you claim!

But, to a very large extent, full understanding isn't needed. Realising it is the case (at least for some) is what matters. Knowing that adding a bit of T4 could be the factor that makes the difference.

Much science starts with simple observation. Followed by up to centuries of discussion and argument about why it is the case. Theories created, 'proved', dismissed, replaced, revived. But not one word of theory changes the original observation.

I love a good theory. But it isn't always necessary to have one, and they can divert from empirical, pragmatic and eminently effective approaches.