That depends on the actual production or how underproductive your thyroid is, being a supplement Levothyroxine is a T4 Medication, prescribed to replace the hormone your lacking, so every person is different, average time for blood work is 4-6 weeks, in the US it is 6 weeks between labs, they judge that by the time a dosage increase has an effect and shows up in blood tests. Do you have any test results with the ranges they provided, being in the UK, I doubt they did Free T3 and Free T4, but if you have them, please post with ranges for more advise and member comments. Thank You FTB4
Thank you very much for your reply. I will see what information I can get from my doctors
As a UK member, there are some important things you should become familiar with. I won't repeat here, but you can get the info from reading the thread under the name of a fellow UK member, LionHeart_62, near the bottom of this page.