Parents often hear that height stops once growth plates close and wonder how that affects treatment decisions. Understanding growth hormone therapy before growth plates close is essential because the effectiveness of therapy depends almost entirely on remaining growth potential.
Growth hormone can only increase height while bones are still lengthening. After closure, treatment cannot add height regardless of dose or duration.
What Are Growth Plates?
Growth plates are soft cartilage areas at the ends of long bones.
During childhood they continuously produce new bone, allowing children to grow taller.
During puberty:
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Hormones accelerate growth
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Plates gradually harden
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Plates permanently close
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Height stops
This process happens over several years, not overnight.
Why Therapy Works Only Before Closure
Growth hormone stimulates these plates to lengthen bones.
If plates are open → bones can grow
If plates are closed → bones cannot lengthen
So treatment success depends on time remaining, not just age.
When Growth Plates Typically Close
Although individual timing varies:
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Girls often finish growth mid-teens
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Boys often finish growth late teens
Some children close earlier or later depending on puberty timing.
A bone age X-ray determines this more accurately than age alone.
Benefits of Starting Before Closure
Beginning therapy while plates remain open allows:
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Faster yearly growth
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More years of response
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Higher final adult height potential
Earlier treatment does not force abnormal growth — it allows normal growth to occur longer.
What Happens If Started Late
If growth plates are nearly closed:
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Growth improvement may be limited
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Only small additional height may occur
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Treatment duration becomes shorter
Once fully closed, height increase is no longer possible.
Signs a Child Still Has Growth Remaining
Children may still benefit if they:
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Continue growing each year
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Recently entered puberty
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Have delayed bone age
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Are below predicted family height
Only imaging can confirm growth plate status.
Why Evaluation Matters Early
Growth changes gradually over years. Waiting until growth stops removes the opportunity to improve final height.
Early assessment identifies whether growth time remains and whether therapy could help.
The Takeaway
Growth hormone therapy before growth plates close is effective because the bones can still lengthen. The earlier appropriate treatment begins, the greater the opportunity to reach natural height potential.
After closure, height cannot be increased — making timing the most important factor in treatment decisions.
Learn more about pediatric growth evaluations and treatment options at www.hghforchildren.com.
Dr. Devin Stone
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