What is an optimal Reverse T3 level?
The short answer
Optimal Reverse T3 is under 12 ng/dL, as stated on video.
Most labs call Reverse T3 high only above 25. So your report can call 19 normal while it sits above the optimal ceiling.
“if someone's TSH is between about 0.5 and 2.0 and they're free t3 is above 3.0 and their reverse t3 is below 12 I find it very hard to see how they could have hypothyroidism”
“if someone's TSH is between about 0.5 and 2.0 and they're free t3 is above 3.0 and their reverse t3 is below 12 I find it very hard to see how they could have hypothyroidism”
What each range means
- under 12 ng/dL Optimal
- 12–25 ng/dL Normal on most reports. Above optimal“if someone's TSH is between about 0.5 and 2.0 and they're free t3 is above 3.0 and their reverse t3 is below 12 I find it very hard to see how they could have…” Dr. Peter Attia · 7:42 →
- over 25 ng/dL Most labs flag this as high
What Reverse T3 measures
An inactive form of thyroid hormone your body makes instead of the active one.
Your body makes more of it during illness, starvation and stress. It reads as a sign the body is throttling thyroid activity.
Why it matters, on the record
“the amazing thing is that whereas T3 is a super active molecule, reverse T3 is dead. It it has less activity than T4 even.”
Common questions
What is an optimal Reverse T3 level?
Under 12 ng/dL, from a quote on video (Dr. Peter Attia, 10:02).
What is a normal Reverse T3 level?
Most US labs print 8–25 ng/dL. Your report grades you against that range. It exists to catch disease, not to describe your best.
What does your Reverse T3 number mean?
On a typical lab range, under 8 ng/dL is low, 8 to 25 is normal and over 25 is high. Your own report prints its range next to your number, and that is the one your lab uses. The optimal range on this page comes with the quote behind it.
Is Reverse T3 of 19 normal?
A typical lab range calls it normal. On video, the optimal ceiling is 12 ng/dL (Dr. Peter Attia, 10:02), so by that line it is high.
What does the Reverse T3 test measure?
An inactive form of thyroid hormone your body makes instead of the active one. Your body makes more of it during illness, starvation and stress. It reads as a sign the body is throttling thyroid activity.