meto
Biomarker

IGF-1

Also known as Insulin-like Growth Factor 1 · Somatomedin C

The primary blood marker of growth-hormone activity — the lab that gates any GH-axis protocol and the one re-checked at month 3.

Definition

Insulin-like Growth Factor 1 is secreted by the liver in response to pituitary GH and mediates most of GH's peripheral effects on muscle, bone and soft tissue. Because IGF-1 has a ~15-hour half-life, it reflects average GH output more reliably than GH itself. It's the baseline required before P2 and P4; the therapeutic target is the upper half of age-adjusted range. Values above the reference range prompt dose reduction.

$149 panel.
A clinician reads it in 24 hours.

Order the Peptide Readiness Panel, draw at a Quest or LabCorp near you, and your clinician sends back a matched protocol with a confidence score.