By Dr. Kelli Davis, Pediatric Endocrinologist, Life Pediatric Endocrinology
If you’ve ever wondered “when do growth plates close?” the answer is more important than you might think—especially if you’re tracking your child’s height and growth potential. Growth plates are the “engines” of bone lengthening, and once they fuse, no more height can be added. As a pediatric endocrinologist specializing in growth and bone health, I’ll explain when growth plates close in boys and girls, how to tell if they’re still open, and why this timing matters for your child’s final height.
Growth plates—also called physes—are soft, developing areas of cartilage located at the ends of your child’s long bones (like the femur, tibia, and radius). They create new bone tissue during childhood and adolescence.
Open growth plates mean the bone can still lengthen.
Closed growth plates mean that bone has reached its final length.
Understanding whether growth plates are open or closed helps guide decisions about height expectations, sports safety, and treatment options.
Research using MRI and long-term growth studies shows that timing depends on hormones, genetics, and overall health:
Girls – Most close between ages 14–16, often within 1–2 years after the first menstrual period.
Boys – Most close between ages 16–18, sometimes later if puberty starts late.
There’s a wide range of normal, so some children close earlier and others later. Factors like hormone levels, nutrition, and chronic health conditions can shift this timeline.
The most reliable method is a bone age test—an X-ray of the hand and wrist. It compares bone development to age-based standards to predict remaining growth potential.
In certain cases, MRI can assess specific growth plates, like those in the knee or hip, with even greater detail.
Knowing when growth plates are closing is critical for:
Height Prediction – Bone age testing helps estimate your child’s final height.
Treatment Decisions – Growth-promoting treatments like growth hormone therapy or puberty-delaying medications work only before plates close.
Sports Safety – Open plates are more vulnerable to fractures in high-impact sports.
Studies have identified key influences on growth plate closure:
Hormones – Estrogen triggers closure in both boys and girls.
Genetics – Family patterns often predict timing.
Nutrition & Health – Illness or malnutrition can delay closure; excess hormones can accelerate it.
Activity & Lifestyle – Sleep, exercise, and overall wellness support healthy growth.
(References: Kvist et al., 2021; Kraus et al., 2011; longitudinal growth studies in lower extremity physiology)
In certain medical situations, treatment can slow the pace of growth plate closure—but only when it’s safe and necessary under specialist care. For example, medications like an aromatase inhibitor can sometimes help delay closure by reducing estrogen’s effect on the growth plates. This approach is highly individualized and only recommended after a thorough evaluation by a pediatric endocrinologist.
We take an integrative endocrinology approach at Life Pediatric Endocrinology, combining advanced medical care with nutrition, bone density optimization, and hormone balance strategies to support healthy growth.
If you want to learn more about strategies to support open growth plates, see our guide: How to Keep Growth Plates Open Longer.
Seek evaluation if your child:
Is shorter or taller than expected for their age
Shows early or delayed puberty signs
Has a slowing growth rate
Needs a final height prediction for sports or health planning
We’ll assess growth plates with imaging, labs, and a detailed health history to guide your family on next steps.
Growth plates typically close in the mid- to late-teen years, but timing varies for every child. Identifying whether plates are open allows parents and doctors to make timely, informed decisions about height potential and health.
If you’re wondering whether your child’s growth plates are still open, our team at Life Pediatric Endocrinology is here to help you find out—and to create a personalized plan for your child’s best possible outcome.
Disclaimer: This article is for educational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare provider with questions about your child’s health.