Thyroid
Free Thyroxine Index
%View
Thyroid
Triiodothyronine (T3)
T3 is your active thyroid hormone—it drives metabolism, body temperature, energy, and even mood. It’s more potent than T4, and when T3 is low, everything can feel sluggish. When it’s high, things speed up: metabolism, energy, even anxiety.
- Unit
- ng/dL
- Health impacts
- Mood · Metabolic Health · Energy · Fat Loss
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
90.0ng/dL
LowOptimal 80.0–100.0High
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.
Order a test
Pick the lab that fits your day.
LabCorpTest code: 002188$14.99
Keep exploring