What is an optimal IGF-1 level?
The short answer
An optimal IGF-1 level is 120–160 ng/mL. That is Dr. Rhonda Patrick's number. You can watch her say it below.
Most labs call IGF-1 low only under 50. So your report can come back normal at 85 while you sit under the line she draws.
“showing a U-shaped relationship between igf-1 levels and mortality both very high and very low igf-1 were linked to higher death rates what was the optimal range it was actually around 120 to 160 nanog per milliliter”
Where a number lands, and who said so
- under 50 ng/mL Most labs flag this as low
- 50–120 ng/mL Normal on most reports. Below optimal
- 120–160 ng/mL The range Dr. Rhonda Patrick draws Dr. Rhonda Patrick · 30:14 →
- 160–300 ng/mL Normal on most reports. Above optimal
- over 300 ng/mL Most labs flag this as high
What IGF-1 measures
The hormone through which growth hormone does most of its work.
It is a steadier readout than growth hormone itself, which pulses through the day.
Checked against MedlinePlus — IGF-1 (Insulin-like Growth Factor 1) Test.
One of the doctors we cite, on why it matters
“showing a U-shaped relationship between igf-1 levels and mortality both very high and very low igf-1 were linked to higher death rates what was the optimal range it was actually around 120 to 160 nanog per milliliter”
Common questions
What is an optimal IGF-1 level?
120–160 ng/mL, according to Dr. Rhonda Patrick.
What is a normal IGF-1 level?
Most US labs print 50–300 ng/mL. Your report grades you against that range. It exists to catch disease, not to describe your best.
What does your IGF-1 number mean?
Under 50 ng/mL, your report marks it low. Between 50 and 300 it prints as normal. Over 300, your report marks it high. Where the people we follow draw their own line is above.
Is IGF-1 of 85 normal?
Your lab will call it normal. Dr. Rhonda Patrick puts the floor at 120 ng/mL, so by that number it is low.
What does the IGF-1 test measure?
The hormone through which growth hormone does most of its work. It is a steadier readout than growth hormone itself, which pulses through the day.
Where does this number come from?
Dr. Rhonda Patrick, on video. The link above jumps straight to that minute.