I suspect the people who find NDT to be life changing are those whose doctor’s won’t prescribe them ANY T3 whatsoever.
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 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.
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.
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:
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:
- 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
https://www.holtorfmed.com/t2-the-lesser-known-thyroid-hormone/
- 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"
The main source of T2 is most likely peripheral tissues (rather than the thyroid)
Yes, I would say it has to do with the thyroglobulin content binding up some up the T3 so it is less bioavailable.
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.