I realize this is a UK forum, but I thought my sisters and brothers across the sea might be interested in what the Yanks are doing. This Guideline from the American Thyroid Association makes me grit my teeth:
"While short-term studies suggest that synthetic liothyronine may have beneficial effects on weight, lipid levels, and depression in hypothyroid patients, long-term controlled clinical trials using a longer acting form of triiodothyronine are needed before this treatment can be recommended for routine clinical use. "
Another way of saying this is: Patients who still feel like crap, despite us giving them our very best drug, should just keep on suffering for as long as it takes. Long-term clinical studies take years to complete, and then even more years for the committees of experts to incorporate the findings into their practice guidelines. If anyone ever does conduct such a trial, then--and only then--can the patients can be treated with a drug that works.