Thyroid UK and this site have been an enormous help to me. When I first started searching the sites many of the messages said either 'T3 only ' therapy worked best or Natural Desicated Thyroid (NDT) was the best treatment. There was a lot of advice about changing from one regime to another. The possibility of taking a combination of synthetic and NDT did not even occur to me. Through slow experimentation and careful record keeping I have discovered what is best for me. I take the synthetic medication in the morning and the NDT in the evening. The mcgs of T3 I take is equal to a quarter of the mcgs of T4.
I know we are all different and what works for one does not work for another. I just wanted to highlight what may be an answer for others, particularly people who are new to this site.