Thyroid
Free Thyroxine Index
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Thyroid
Thyroxine (T4)
Total T4 measures the full amount of thyroxine in your blood—both bound and unbound. T4 is the main hormone produced by your thyroid and acts as the precursor to T3, the active form. Most of it is bound to transport proteins and inactive, so while it gives you a good sense of production, it doesn’t reflect actual activity without looking at T3, T3 Uptake, or Free T4. Still, it’s a valuable marker for thyroid output and upstream hormone availability.
- Unit
- ug/dL
- Health impacts
- Energy · Thyroid
In your dashboard
Your trend, against your optimal range.
Example data · how your trend would appear once you test
At every level
What we'd do at any value.
Exploring
9.00ug/dL
LowOptimal 6.00–12.00High
In your optimal zone
Habits that hold this position.
No specific guidance for this zone yet. We're working on it and will update this soon.
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