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/