This is an excerpt from link below :-
A major study reported on in the European Journal of Endocrinology, looked at the controversial issue of treatment with synthetic T3 as a supplement to T4-only (levothyroxine) therapy for hypothyroidism.The study found that the combination of T4/T3 is superior to T4 only/levothyroxine treatment for hypothyroidism.
verywell.com/t3-superior-t4...
Other excerpts:
1. A 2003 study conducted by the government, with patients at Walter Reed Medical Center, reported that Natural Desiccated Thyroid drugs were a safe alternative to levothyroxine-only therapy.
2. (from a study conducted in 2005!)
Patients preferred combined LT4/LT3 therapy to usual LT4 therapy... Decrease in body weight was associated with satisfaction with study medication...the outcome of this study does not preclude the possibility that a certain subgroup of patients may benefit from combined LT4/LT3 therapy."
3, According to Dr. Woliner: "Rather than focusing on a specific range of various lab tests, I think of "optimal treatment" based upon my patients' symptoms [1].
More than any one laboratory test, the absence of hypothyroidism symptoms or side effects from therapy is what I am looking for [2]."
verywell.com/dr-ken-woliner...
4. Now, back to the issue of whether or not you might benefit from the addition of T3. The operative question is: will your doctor be willing to even discuss this with you, much less prescribe it? There's no definitive answer.
If you say to the doctor, "Could I benefit from some additional T3?" the response is likely to fit one of four possible scenarios...
A. The doctor rolls his/her eyes, snorts with derision, shakes his/her head, or otherwise makes it clear that he/she has no interest whatsoever in further discussion about T3.
B. The doctor respectfully says, "that's not something I'm comfortable with. Sorry."
C. The doctor thinks about it, and says, "well, let's take a look at your Free T3 level to see what it looks like and then make a decision.
D. The doctor says, "that's certainly a possibility. Let's try a very low dose of T3 and see how you feel on it. But let's make sure there are no contraindications for you...
verywell.com/thyroid-patien...
A groundbreaking 1999 study reported in the New England Journal of Medicine found the quality of life of thyroid patients life improved with the addition of a T3 drug to levothyroxine-only therapy.
