Thanks for getting back to me.
I’m not taking any medication. My TSH and free T4 were normal, only the free T3 was down. I’m not quite sure how this all computes and hoping someone at the surgery will explain.
Although going by your reply it will probably be “next steps”
Maybe sort out my low ferritin first.
Definitely sort out the low ferritin as it is important in your overall metabolic health, and if low, any Levothyroxine added would not be taken up optimally anyway.
What is your diet like? Are you perchance on a reduced or low carb diet? There is a school of thought suggesting those living a LC lifestyle will naturally have slightly lower T3.
Thing is, T3 is the only active thyroid hormone. Your pituitary gland in the brain generates TSH (stimulating thyroid activity). That thyroid activity is T4, which then by black magic our bodies convert to T3, which is the real get up and go of the thyroid hormones.
To be honest, thyroid is complex, and if your TSH is "in range" you are unlikely to gain any traction from your GP. Obviously where it is in range is important, with an ideal of 1-2, representing euthyroid. Much more than 2 could, and I stress could suggest the thyroid may be struggling. That is when the T4 result comes into play and that depends where that is in range, but again, if it is in range, I doubt you will achieve traction.
Sooooooooooooooo, for now, work on the ferritin. With it in a better place, your thyroid results my well improve, but as I say, if you are broadly "in range", traction will be tricky to achieve.
As you may have guessed, I have been through this loop, but now in a better place. Typically for me, my thyroid challenges are not typical, classic or even remotely usual, but it is what it is. My comments are based on my experiences and self education over a period of years.
If you want to learn more about your thyroid, it could be worthwhile looking at Health Unlocked where there is an excellent and knowledgeable community:
https://healthunlocked.com/thyroiduk/posts