Hey Reader, Dr Karl here.

Higher is not always better, but too low is most common.
The marker where both ends raise your mortality

IGF-1 is not a score.
It is an instruction.
​
Growth hormone leaves the pituitary, reaches the liver,
and the liver answers by producing IGF-1.
That IGF-1 then goes out to bone, to muscle, to the brain, to the heart, and fat cells as well ... and to every cell in your body with the same message:
build, repair, divide, do not die yet. You can see why people assume more is better.
​
Growth sounds like youth.
It is not that simple, and the mortality data is not ambiguous about it. A meta-analysis of nineteen separate studies (referenced below) just under thirty-one thousand people,
found the relationship between IGF-1 and all-cause mortality is U-shaped.
​
​Low IGF-1 carried a thirty-three percent higher risk of death
​compared to the middle.
High (OUT OF RANGE) IGF-1 had a twenty-three percent higher risk.
The lowest-mortality band landed at roughly 120 to 160 ng/mL.
A separate analysis of nearly 381,000 people in the UK Biobank found the same U shape.

Both ends. Not one.
Judi's's IGF-1 in 2008 was 254, at age 53.
That sits out on the right arm of that curve, in the half almost nobody worries about,
because almost everybody has been taught to worry about low.
​
Today, at 71, she runs 137. That sits inside the trough, the ideal middle.
I want to be careful about what that does and does not prove. I am not going to tell you surgery normalized her number, because nobody drew an IGF-1 after her operation. That test was never ordered either. What I will tell you is this. When her 254 came back in 2008, not one of the three physicians who saw it had any idea what it meant, and the reason is that the printed reference range on a lab sheet does not tell you where the risk lives. It tells you where the middle 95 percent of some population sits. Those are different questions.
​
Do you know your IGF-1 number? Most people have never had it run once.

Here's the full story:

To your health and longevity,

Dr. Karl Goldkamp
Keto Naturopath

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