Total T3 Total Triiodothyronine (T3)
All your active thyroid hormone, the bound and the free added up.
Also printed asTotal Triiodothyronine · T3 · Triiodothyronine
What it measures
All of the active thyroid hormone, bound and free together.
Like total T4 it shifts with carrier protein, so free T3 is the number to trust when the two disagree.
Why it matters for how long you stay well
The free measurement is the one that reflects what your cells can actually use, so this total is context rather than the number to act on.
How it shows up in daily life
Like the other total, it is nudged by pregnancy and the pill without the gland changing at all.
High and low readings
When it reads high
An overactive thyroid, or more carrier protein.
When it reads low
Reduced conversion, illness, or less carrier protein.
What moves it
Daily life
- pregnancy
- serious illness
- very low-calorie dieting
Medicines known to shift it
- thyroid hormone replacement (raises it)
- oral contraceptives (raise it)
- steroids (lower it)
Listed so a result can be read in context. It is not advice to start, stop or change any medicine; that decision belongs with your physician.
Common questions
What does Total Triiodothyronine (T3) measure?
All of the active thyroid hormone, bound and free together. Like total T4 it shifts with carrier protein, so free T3 is the number to trust when the two disagree.
What does a high Total T3 result usually mean?
An overactive thyroid, or more carrier protein.
What does a low Total T3 result usually mean?
Reduced conversion, illness, or less carrier protein.
What is the usual reference range for Total T3?
A broad adult reference band is 0.6–2 ng/mL. Labs differ, so read your result against the band printed on your own report.
Educational only, not a diagnosis. A single number means little without your history and the rest of your panel, so discuss your own results with your physician.
Typical adult reference band
- Adults
- 0.6–2 ng/mL
Labs differ. The band printed on your own report is the one that applies to your result.
Reported in ng/mL, ng/dL
Ageing relevance
2/5
Relevant to the ageing of one organ, or to disease screening.
Worth knowing
It falls during any serious illness even when the thyroid is fine, which makes it a poor test in someone who is unwell.
Have a report with this marker on it? Read it in context.
Upload it to Oraia, our health-intelligence tool, for a plain-language read of your markers that a Genoryx doctor can review.
Your biological age is a number you can measure.
Start with the 400+ parameter entry assessment and a 60-minute physician consultation at either Hyderabad clinic. Open seven days, 11 AM to 9 PM.
Book a consultation