06/07/2026
Most parents think of a growth spurt as "suddenly buying bigger shoes." But what's actually happening inside your
child's body is a precise, hormone-driven biological process.
Here's the sequence:
1. The pituitary gland — a small gland at the base of the brain, releases growth hormone. Most of this release
happens during deep sleep, which is why quality rest is non-negotiable during childhood.
2. Growth hormone signals the liver to produce IGF-1 (Insulin-like Growth Factor 1). This protein is what actually tells
the body to grow.
3. IGF-1 reaches the growth plates — soft cartilage tissue at the ends of your child's long bones. New bone cells are
produced here, which is where height gain physically happens.
4. As puberty progresses, growth plates gradually harden and close. Once closed, no further height growth is possible.
This is why the window matters. And why knowing where your child is in that window, through a bone age assessment, is so valuable.
Book a Growth Plate Exam at igrowclinic.com or call (909) 333-7153.