Free unbound IGF‐1 or IGF‐1 bioavailability, in the disc specifically, is a better measure of the activity of the GH/IGF‐1 pathway in relation to IDD rather than total serum or total protein expression level, which are the methods used almost exclusively in previous papers studying IGF‐1 and IDD. This evidence concerns the gene IGF1 and intervertebral disk degenerative disorder.