09/09/2026
Your thyroid panel can come back "normal" and you can still not feel like yourself.
TSH measures your pituitary, not your thyroid directly. Free T4 is a storage hormone, it doesn't confirm conversion. Free T3 is the active form your cells actually use and it's rarely tested. Reverse T3 can quietly take T3's place during stress, illness, or inflammation and it's not on a standard panel at all.
Standard ranges are built to catch disease, and they do that well. Functional ranges are narrower, because the goal is different: picking up on early signs of dysfunction before they progress that far.
**Reference ranges vary between labs. SANA optimal reflects our clinical targets we use in functional practice.**