Hello,
The fact you took one dose doesn't mean that you have to take it a life long, is not dependent on that. However, if there is an increasing
hormone deficiency taking treatment is necessary.
It means that your body is not producing enough
thyroid hormone and you have to take replacement like
thyronorm as prolonged hormone deficiency may harm your body.
It's not a drug like others it is to replace a hormone which should be naturally present in your body.
As for whether you'll have to take it lifelong that depends on the cause of the hormone deficiency, if there is nonreversible damage you may have to take it lifelong, you should discuss with your
endocrinologist the possible cause as I don't know your history and what tests you've had.
Hope I have answered your query. Let me know if I can assist you further.
Take care
Regards,
Dr Olsi Taka, Neurologist