Is it because they have useless doctors?
The other day I had to visit the doctor because of another (unrelated to my hypo) problem, and we got to talking about medication. I told him that because my recent blood test didn't test for T3 I was thinking of buying a private test.
He told me not to do that he'd do another one for me and he added another couple of tests to it too.
Then I asked him if the cost of T3 was why the NHS didn't prescribe it. He said they don't really like doctors to prescribe but that if I needed it, there wouldn't be a problem because he has a few patients who are on T3.
That made me wonder why so many here are asking about where they can buy it privately from.