For those of us who are symptomatic, the T3 in NDT is really helpful in getting symptoms quelled much faster than by using Thyroxine (as is your Levo) alone. Levo takes weeks to take hold and is dependent on many nutrients being in place to facilitate conversion of Thyroxine (T4) into the active thyroid hormone Triidothyronine (T3).
Hypothyroidism is caused by the lack of adequate T3 in all the cells of the body. When T3 is lacking, the body takes it from other non-vital areas. Soon, there is a major deficit of T3 and symptoms of such begin to abound.
This is why millions of hypo sufferers are diagnosed for years and decades with all kinds of muscular syndromes. None of the usual medications does a thing for any of them because they don't understand the root cause.
Fibromyalgia is no doubt the best example of such, as it radiates pain from head to toe in recognizable areas. Fibromyalgia's symptoms are caused by the lack of T3 at the cellular level. They may call it Fibromyalgia, but by any name it is still Hypothyroidism. This is why those who are lucky enough to have a doctor who thinks outside the "standard protocol" box and gives them thyroid hormone, find great relief from the debilitating symptoms of "Fibromyalgia" (root cause Hypothyroidism).
I know that NDT will work for you as long as you have your nutrients in place. T4 needs those nutrients to be able to convert into T3. Check nutrients vital to conversion and make sure you are supplementing them if necessary. If you have any issues with low stomach acid (called "too much" stomach acid most times), be sure to look into a Hydrochloride (HCL) replacement. It will help increase the hydrochloric acid in your stomach so you can absorb nutrients from your foods and supplements.