NDT vs. T4/T3 combo

[Hyperflux]

How does NDT compare to the equivalent T4 and T3 combo subjectively? I know that NDT has other thyroid hormones like T1/T2 and my endo is open to me trying it. I'm currently on 100ug Synthroid and 10ug Cytomel.

 

[Wonkmonk]

It is often reported that some patients feel better on NDT compared to synthetic hormones. The reason is unknown. It's probably not the T1/T2, because what you get from NDT is a very small fraction of the T1/T2 in the body. The overwhelming part of T1/T2 is a product of enzymes deiodizing T4 and T3 to T2 and finally T1 (removing one iodine atom in each step). As of right now, it is also suspected that T2 and T1 are metabolically inactive and don't have any role in the organism, they are just intervening steps to deactivate and finally dispose of T3 and T4.

But note that NDT has a different relation of T3 and T4. A grain is usually ~40 µg T4 and ~10µg T3. You can't replicate your current 100/10 split with NDT alone. You would need to either take a combination of 1 Grain NDT plus 60µg Synthroid (which is not available, but you could go with 50 µg plus 1/2 25 µg tablet) or you'd go with probably about two Grains of NDT instead of your 100/10, which would be about 80/20. Usually 1 µg T3 equals about 3-4 µg T4 with respect to metabolic activity, so the 80/20 should be roughly equal to your 100/10. But you'd still have to get tested and see if your blood tests are ok on the new regime, and you might have to make some adjustments, which probably takes a few months.

After trying NDT for several months, I returned to the synthetic hormones again. It didn't have a lot of benefit for me, was more expensive, and I wasn't comfortable with taking so much T3.

 

[Ema]

I suspect the people who find NDT to be life changing are those whose doctor’s won’t prescribe them ANY T3 whatsoever.

That said, some people will always have a better time with one or another. It’s all trial and error.

I take Tirosint and Cytomel 88/5-10 and it works for me.

 

[Learner1]

I was on T3 only for 5 years, started due to sky high rT3 and Hashimotos. I can't take NDT due to allergies to the fillers. Currently, I take 137mcg compounded T4 and 50mcg liothryonine, along with a little iodine, and do fine. The only "problem" is my TSH is suppressed" which freaks out conventional doctors, but my ME/CFS specialist and functional medicine doctors think its fine, as long as FT3 and FT4 are mid range, which they are.

Everyone is different, and it seems that the patients having problems are the ones whose doctors try to practice "cookbook medicine," rather than dealing with them as individuals. Some curiosity and thought can produce better results.

 

[Wonkmonk]

I suspect the people who find NDT to be life changing are those whose doctor’s won’t prescribe them ANY T3 whatsoever.

I have seen several reports of patients in thyroid forums who tried synthetic T3, but could not tolerate any, but had no problem tolerating NDT with much more T3 inside. For some reason, the natural T3 seems to have a different effect than the synthetic stuff in some patients. It may also have to do with pharmacodynamics, i.e. the NDT having another (slower?) absorption profile.

 

[Ema]

I have seen several reports of patients in thyroid forums who tried synthetic T3, but could not tolerate any, but had no problem tolerating NDT with much more T3 inside. For some reason, the natural T3 seems to have a different effect than the synthetic stuff in some patients. It may also have to do with pharmacodynamics, i.e. the NDT having another (slower?) absorption profile.

Yes, I would say it has to do with the thyroglobulin content binding up some up the T3 so it is less bioavailable. But that may also create problems for those with autoimmune thyroiditis, as it's possible to react to the pig thyroglobulin just like the human.

I don't have any issue with NDT, per se. I used it myself for a long time until I discovered Tirosint (which was like turning a lightbulb on). But it's sometimes a bit annoying to see it hailed by thyroid groups as the ONLY solution when in fact there are many choices.

 

[Learner1]

Agreed. I find it maddening to be shouted down by the NDT crowd that taking T4/T3 is wrong when the NDT could kill me due to the allergens in the fillers.

There seem to be a lot more intricacies to the various thyroid hormones and related biochemicals and how the body converts, uses, and distributes them for there to be one right way to treat patients.

 

[Hyperflux]

It is often reported that some patients feel better on NDT compared to synthetic hormones. The reason is unknown. It's probably not the T1/T2, because what you get from NDT is a very small fraction of the T1/T2 in the body. The overwhelming part of T1/T2 is a product of enzymes deiodizing T4 and T3 to T2 and finally T1 (removing one iodine atom in each step). As of right now, it is also suspected that T2 and T1 are metabolically inactive and don't have any role in the organism, they are just intervening steps to deactivate and finally dispose of T3 and T4.

But note that NDT has a different relation of T3 and T4. A grain is usually ~40 µg T4 and ~10µg T3. You can't replicate your current 100/10 split with NDT alone. You would need to either take a combination of 1 Grain NDT plus 60µg Synthroid (which is not available, but you could go with 50 µg plus 1/2 25 µg tablet) or you'd go with probably about two Grains of NDT instead of your 100/10, which would be about 80/20. Usually 1 µg T3 equals about 3-4 µg T4 with respect to metabolic activity, so the 80/20 should be roughly equal to your 100/10. But you'd still have to get tested and see if your blood tests are ok on the new regime, and you might have to make some adjustments, which probably takes a few months.

After trying NDT for several months, I returned to the synthetic hormones again. It didn't have a lot of benefit for me, was more expensive, and I wasn't comfortable with taking so much T3.

That sounds like a pain in the ass but I'll talk to my endo.

 

[Hyperflux]

Also found this piece of info, any thoughts?

A lot of people mention similar results. T4 + T3 is considered wayyy better than T4 only. And NDT is about the same or marginally better than synthetic combo. The objective difference (and why i take NDT) is because NDST also contains T2, T1. Basically the complete thyroid hormone in the right ratios. Scientists dont have the other thyroid hormones totally figured out but they must be important in some way, so i feel better knowing I'm getting everything

What are the benefits of T1/T2?

"T2 belongs to the family of iodine-dependent thyroid hormones known as iodothyronines, although it is generally considered less active than T4 and T3, as are rT3, 3’3’T2, and 3’T1. It was previously thought to be a catabolite of T3, but studies have shown that T2 is made by the deiodination of T3 and rT3 (possibly more so from rT3) and mimics the effects of T3 on energy metabolism. So while it does appear to be closely related to T3, it has been demonstrated to be metabolically active, possessing its own mechanisms of actions separate from T3. Here are some of the differences that have been found between the two thyroid hormones:

• T2 appears to be more specific to the mitochondria, as opposed to the DNA-based actions of T3
• T2 has weaker protein binding potential than T3
• The conversion of T3 (or rT3) to T2 is not affected by fasting like the T4 to T3 conversion is
• The main source of T2 is most likely peripheral tissues (rather than the thyroid), partly evidenced by studies showing that skeletal muscle acts as a target for the hormone

This finding that skeletal muscle is a target for T2 and that it helps to prevent fat storage and insulin resistance is significant because it could possibly explain why T2 appears to play a similar but distinctly different role than T3. One theory is that T2 is the peripheral mediator of thyroid hormones’ effects on energy metabolism. Although the exact mechanisms by which T2 exhibits changes on metabolism are not yet completely understood, the following summary of the scientific findings regarding its actions are impressive enough that some healthcare providers have begun to use it in clinical practice:

• rapidly affects mitochondrial respiratory parameters
• increases resting metabolic rate (RMR), despite lower circulating T4 and T3
• decreases adiposity (both in general and specifically abdominal fat) by increasing fat burning
• decreases triglycerides and cholesterol levels
• decreases fatty liver markers
• reduces diet-related weight gain
• stimulates glucose consumption and growth hormone
• may relieve diabetic neuropathy
• may reverse impairments in mitochondria
• activates SIRT1 and AMPK – important for healthy aging and preventing insulin resistance
• improves resistance to cold among hypothyroid subjects (in an animal model)
• increases mitochondrial capacity to import and oxidize fatty acids"

https://www.holtorfmed.com/t2-the-lesser-known-thyroid-hormone/

Those sound like some pretty awesome benefits to try out NDT over T4+T3. All references to the literature are posted in that link at the end. I will show this to my endo tomorrow when I see him and see what he thinks. Last time he told me that some patients simply respond better to NDT and that could be due to many factors including the T2/T1 or others.

 

[Wonkmonk]

Quoting from the quote:

The main source of T2 is most likely peripheral tissues (rather than the thyroid)

I do not doubt NDT has benefits for many people but I do not believe T2 is the reason. The T2 in NDT is very low, just a few µg, and more importantly, 99% of the T2 in a healthy person is made from T3 and T4. If you get thyroidectomy and your thyroid doesn't make any more T2 and you switch to synthetic hormones that don't contain any T2, you are just using about 1% of the total T2 in your body.

So whatever is the reason why NDT has benefits for some patients, T2 is likely not the reason.

I rather suspect that we don't build the T4 and T3 hormones perfectly when they are produced synthetically and some patients don't do well with these minor imperfections, but that's just my personal speculation.

 

[Wonkmonk]

Yes, I would say it has to do with the thyroglobulin content binding up some up the T3 so it is less bioavailable.

That would mean that you just get less T3 from the NDT, but if you want to have the same TSH as with synthetic hormones that means you just have to take a higher dose. I wouldn't say bioavailability is the most likely reason why some people do better. Otherwise they could just take less synthroid and do just as well.

I have another suspicion, I have not seen any good evidence whether then thyroglobulin bonding of the thyroid hormones in NDT are opened before it goes in the blood stream in free form or if it goes into the blood while still connected to the thyroglobulin. Synthetic hormones are in free form and are directly active once they are in the blood and that leads to problems in some patients a few hours after taking the hormones. If NDT hormones go into the blood stream while still bound to thyroglobulin, they are not active immediately and will be used later and that might make people tolerate it better.

But as I said, I don't know if that's true, it may well be that the bonds are destroyed in the gut and the NDT also goes into the bloodstream in free form.

 

[Wishful]

Synthetic T4 had no effect on my symptoms. Neither did NDT. T2 had a huge effect, and continues to have that effect. I require one 100 mcg capsule of T2 every 21 days to prevent my symptoms increasing severely and remaining at a new much lower baseline. Supplemental iodine works just as well for me as T2, so I assume my body is okay at converting iodine to T2. I just need an abrupt boost of T2 every 21 days to reset something. Note that while I seem to convert iodine to T2 well enough, supplemental T4 and T3 did not contribute noticeable to my T2 level. I don't understand endocrinology well enough to know how much T2 the thyroid gland produces directly, rather than by producing T4 and then deiodizing it.

I should also mention that taking more T2 or iodine than the single dose every 21 days doesn't provide a noticeable benefit, nor does taking higher doses. When I tried taking the T2 for several days, I got the boost, but then it tapered off. When I stopped taking it, I had a negative rebound (worse symptoms) for about the same length of time: kind of a mirror image of the boost. I assume it was the thyroid gland's delayed response to artificial changes.

The only way to know whether NDT is better for you than T4 is for you to try it yourself. Likewise for T2. T2 works great for me, but no one else has reported similar benefits from it.

BTW, T2 supposedly is also critical for some RNA transcription. I came across that in a scientific paper years ago.

 

[Hyperflux]

Alright I got prescribed 90 mg dedicated thyroid but I can also switch backbac 100/10ug T4/T3 if I want to anytime. The brand is the Canadian one (Armour I believe). I'll post an update later.

Does NDT release thyroid hormones in a slow release/compounded fashion or is it instant release?

 

[Wonkmonk]

Armour is American.

90mg would be 3 Grains, right? That's way more potent than your current 100/10 T4/T3 combination, assuming similar bioavailability.

Armour NDT is not a slow-release formulation. Slow release containing T4 isn't possible because once you have a meal, the food messes up the absorption rate in an uncontrollable way and you don't get a stable dose. As all T4 containing thyroid medication, NDT must be taken on an empty stomach with at least 30 minutes to any food intake.

 

[Hyperflux]

Armour is American.

90mg would be 3 Grains, right? That's way more potent than your current 100/10 T4/T3 combination, assuming similar bioavailability.

Armour NDT is not a slow-release formulation. Slow release containing T4 isn't possible because once you have a meal, the food messes up the absorption rate in an uncontrollable way and you don't get a stable dose. As all T4 containing thyroid medication, NDT must be taken on an empty stomach with at least 30 minutes to any food intake.

I think it's called "Thyroid" and might be a combination of a 30 + 60 mg pill. I'll have to check at the pharmacy, I hope it's not a generic.