fT4 in Serum

Free T4 is the circulating thyroid hormone reservoir that must be converted to become active.
Also known as:
Free Thyroxine
S-fT4
Free T4
.

fT4 ranges

Interpret your result
"Normal" lab range for fT4 is between 0.93 and 1.7 ng/dL:
0.93
1.7
According to Peter Attia, fT4 should be between 0.93 and 1.7 ng/dL:
0.93
1.7
According to OptimalDX, fT4 should be between 1 and 1.5 ng/dL:
1
1.5
According to Rupa Health, fT4 should be between 1 and 1.7 ng/dL:
1
1.7
Optimal thyroid health was associated with fT4 between 0.99 and 1.58 ng/dL:
0.99
1.58
Reduced all-cause mortality was associated with fT4 between 0.98 and 1.13 ng/dL:
0.98
1.13
Optimal range
Optimal range for fT4 appears to be between 0.97 and 1.4 ng/dL:
0.4
0.97
1.4
1.7
3.5

Images:

fT4 on all-cause mortality

fT4 on all-cause mortality

Values associated with percentiles were calculated from table S3b in supplement-1.
134,346 participants
FT4 decrease and then increase during aging

FT4 decrease and then increase during aging

Chinese population with sufficient iodine intake

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Zsolt Szabo
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