Thyroid Hormone Change Armour Thyroid to Tirosint/Cytomel

[susanmhall62]

Hello,

I recently requested to switch from Armour Thyroid 3 grains to a Tirosint Cytomel combination so that I have more flexibility with T4/T3 ratios. I was proposing Tirosint 137 mcg and Cytomel 10-15 mcg and redoing labs in 6-8 weeks.

The CRNP switched my dose to Tirosint 112 mcg + Cytomel 10 mcg which feels like a large drop.

Most recent labs:

FT3 4.5 pg/mL range 2.0-4.4. Slightly over range.

FT4 1.66 ng/dL range 0.82-1.77

TSH <0.005 range 0.450-4.500

B12 451 pg/mL range 232-1245.

I also recently learned that I have the MTHFR C677T heterozygous gene defect. I'm supplementing with the Thorne B Complex #12 and Integrative Therapeutics chewable B12 Active to try to raise the B12 to 700 range.

D 25-Hydroxy 58.5 ng/mL range 30-100

Iron Bind.Cap.(TIBC) 288 range 250-450 ug/dL

Iron 79 range 27-139 ug/dL

Iron Saturation 27%

Ferritin 91 range 15-150 ng/mL

Alkaline Phosphatase 143 IU/L range 44-121 IU/L HIGH.

It could be due to the MTHFR gene defect and less than optimal B12 processing. It is however moving in the right direction ⬇️ from 167 IU/L.

ALT 18

AST 18

I do think that I'm slightly hyperthyroid. Thyroidectomy due to thyroid cancer in 2004. I've been on NDT for most of the past 18 years.

CRNP provider is new as I was trying to find a doctor closer to where I live in Pennsylvania, USA. I can still access care via my current doctor in Chicago via telemedicine if necessary.

Thank you in advance for any insights.

[Poniesrfun]

The 112 mcg T4 isn't too bad as the Armour 3 grains provides 114 mcg T4, But you'll likely feel a difference on the T3 - 27 mcg from Armour down to 10 mcg Cytomel. I might have considered just cutting back half a grain daily and retest in 4 weeks. At minimum I would ask for more Cytomel to take as needed.

Patti in AZ

[susanmhall62 in reply to Poniesrfun]

I'm trying to figure out how the thyroid conversion charts work because the one that I'm referencing says that 112 mcg of Tirosint is the equivalent of somewhere between 1 & 1.25 grains of NDT.

I was on 3 grains of the Armour Thyroid or 114 mcg T4 + 27 mcg T3.

So assuming that the 112 mcg of Tirosint = 1.25 grains does that mean that I'd need to add 1.75 grains of Cytomel or a little less then 50 mcg to get an equivalent 3 grain dose. I'm totally confused.

[Poniesrfun in reply to susanmhall62]

I don't try to do those kind of equivalencies like they do on the charts. They've never made a whole lot of sense to me because we all process T4 and T3 differently. You really can't translate mcg of T4 or T3 directly to grains.

Each grain of desiccated thyroid contains 38 mcg of T4 and 9 mcg of T3. - so this is the basis for your math.

112 mcg of Tirosint is simply 112 mcg of levothyroxine/T4. Which is pretty close to what you were obtaining from Armour.

You were also getting 27 mcg T3 - so you would only want 27 mcg Cytomel/liothyronine (T3) to get an equivalent does. Cytomel comes in 5, 25 or 50 mcg dosages. Because you want to lower your FT3 a tad, I'd go with the 112 Tirosint, use Cytomel 5 mcg tabs to find your appropriate T3 level (maybe something like 5 mcg 3x day depending how you feel) then test in four weeks to check your levels. Your Tirosint dose seems OK but the Cytomel 10mcg dose is likely too much of a change.

I take one grain of NPThyroid twice a day; if I'm more active I take "extra" generic T3 (5 or 10 mcg). Occasionally if I have a cold or something I might skip one NPThyroid. It all seems to level out in the long run. Doctors always seem to want us on a "static" unchanging dose

Patti in AZ

[susanmhall62 in reply to Poniesrfun]

Thank you for your insights. I do notice that in the harsh Pennsylvania winters I need more thyroid hormone to feel optimal. I have a prescription for 112 mcg of Tirosint so maybe I will start low and slow and make small adjustments based on future lab work. I also have extra Cytomel from a previous prescription so I can add more if I need to.