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PubMed This is a summary of 16 peer-reviewed journal articles Updated
Endocrinology · Isolated Growth Hormone Deficiency

Growing Up: Transitioning to Adult Care

At a Glance

When individuals with Isolated Growth Hormone Deficiency reach their final adult height, they must be re-tested to see if the deficiency is permanent. If it persists, adult growth hormone therapy focuses on maintaining bone density, metabolic health, and muscle mass using lower, individualized doses.

As your child approaches the end of puberty and reaches their final adult height, the focus of Isolated Growth Hormone Deficiency (IGHD) care shifts. This period, known as the transition phase, is a critical time for re-evaluating whether the body still requires growth hormone replacement for health throughout adulthood [1][2].

Why Re-testing is Necessary

While growth hormone is essential for increasing height in childhood, many children diagnosed with “idiopathic” (unexplained) IGHD find that their bodies begin producing sufficient amounts of hormone once they reach adulthood [1][2]. This is known as transient GHD.

However, for children with “organic” or “permanent” causes—such as specific genetic mutations (like GH1 deletions) or structural brain differences (like Pituitary Stalk Interruption Syndrome)—the deficiency is much more likely to persist for life [3][4]. Re-testing allows doctors to distinguish between these two groups [1].

The Re-testing Process

Doctors typically wait until the child has finished growing and has been off growth hormone therapy for a short period (usually 1 to 3 months) before re-testing [1]. They use adult-specific stimulation tests, such as:

  • Macimorelin: A newer, oral test that is well-tolerated and highly accurate for diagnosing adult deficiency [5][6].
  • Glucagon Stimulation Test: A common alternative used to measure peak GH levels in the transition phase [7].

The Role of Growth Hormone in Adults

If the re-test confirms that your child still has GHD, the goal of treatment changes from “growing taller” to “maintaining health” [1]. Growth hormone in adults is vital for:

  • Metabolic Health: It helps maintain healthy cholesterol (lipid) levels and cardiovascular function [8][9].
  • Body Composition: GH helps the body maintain lean muscle mass and prevent the accumulation of visceral (belly) fat [8][10].
  • Bone Density: It is essential for maintaining strong bones and reducing the long-term risk of fractures [11][12].
  • Quality of Life: Many adults with untreated GHD report lower energy levels and a decreased sense of well-being [1][13].

How Adult Dosing Differs

Treatment in adulthood looks different than in childhood. While pediatric doses are high and based on weight to push for maximum growth, adult doses are much lower and highly individualized [14][15].

  • Physiologic Dosing: Instead of weight-based calculations, adult dosing is “titrated”—starting low and slowly increasing until the child’s IGF-1 levels are within the normal range for their age [14][16].
  • Monitoring: Adults focus less on the “growth chart” and more on metabolic markers like blood sugar, cholesterol, and bone density scans [16][8].

The transition to adult care is a time to celebrate how far your child has come and to establish a plan that ensures their long-term health and vitality well into the future [1].

Common questions in this guide

Will my child still need growth hormone therapy as an adult?
Many children with unexplained growth hormone deficiency begin producing enough hormone by adulthood. However, those with specific genetic causes or structural brain differences typically require lifelong therapy.
How is growth hormone deficiency re-tested during the transition to adulthood?
Doctors usually wait until a child reaches their final height and stops therapy for one to three months. They then use adult-specific stimulation tests, such as the Macimorelin or Glucagon tests, to check hormone levels.
Why is growth hormone important for adults?
In adults, growth hormone is essential for maintaining metabolic health, lean muscle mass, and strong bones. It also helps preserve energy levels and an overall sense of well-being.
How does adult growth hormone dosing differ from childhood?
Childhood doses are higher and based on weight to maximize height. In contrast, adult doses are lower and highly individualized, starting with a small amount that is gradually increased based on IGF-1 hormone levels.
What happens if an adult stops taking growth hormone when they have a permanent deficiency?
Stopping treatment can lead to decreased energy, loss of muscle mass, increased belly fat, and lower bone density. It also negatively impacts cholesterol levels and long-term cardiovascular health.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Since my child has a specific genetic cause/structural MRI finding, how likely is it that their GHD will persist into adulthood?
  2. 2.When is the best time to perform the re-testing after my child has reached their final adult height?
  3. 3.Which adult-specific stimulation test, such as Macimorelin or the Glucagon test, do you recommend for this transition?
  4. 4.If my child needs to continue GH as an adult, how will the dosing change from their current weight-based pediatric dose?
  5. 5.If the deficiency is permanent, what are the long-term health risks if they decide to stop treatment in their twenties?

Questions For You

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References

References (16)
  1. 1

    Growth hormone deficiency and the transition from pediatric to adult care.

    Tavares ABW, Collett-Solberg PF

    Jornal de pediatria 2021; (97(6)):595-602 doi:10.1016/j.jped.2021.02.007.

    PMID: 33773961
  2. 2

    Growth hormone deficiency in a case of septo-optic-dysplasia due to SOX2 mutation: should we re-test patients during the transition period?

    Gasco V, Matarazzo P, De Sanctis L, Ghigo E

    BMJ case reports 2022; (15(12)) doi:10.1136/bcr-2022-251897.

    PMID: 36581364
  3. 3

    Growth Responses During 3 Years of Growth Hormone Treatment in Children and Adolescents With Growth Hormone Deficiency: Comparison Between Idiopathic, Organic and Isolated Growth Hormone Deficiency, and Multiple Pituitary Hormone Deficiency.

    Lim HH, Kim YM, Lee GM, et al.

    Journal of Korean medical science 2022; (37(11)):e90 doi:10.3346/jkms.2022.37.e90.

    PMID: 35315601
  4. 4

    Identifying patient-related predictors of permanent growth hormone deficiency.

    Mericq V, Iñiguez G, Pinto G, et al.

    Frontiers in endocrinology 2023; (14()):1270845 doi:10.3389/fendo.2023.1270845.

    PMID: 37881494
  5. 5

    Macimorelin as a Diagnostic Test for Adult GH Deficiency.

    Garcia JM, Biller BMK, Korbonits M, et al.

    The Journal of clinical endocrinology and metabolism 2018; (103(8)):3083-3093 doi:10.1210/jc.2018-00665.

    PMID: 29860473
  6. 6

    Sensitivity and specificity of the macimorelin test for diagnosis of AGHD.

    Garcia JM, Biller BMK, Korbonits M, et al.

    Endocrine connections 2021; (10(1)):76-83.

    PMID: 33320108
  7. 7

    Accuracy of Glucagon Testing Across Transition in Young Adults With Childhood-Onset GH Deficiency.

    Fava D, Guglielmi D, Pepino C, et al.

    The Journal of clinical endocrinology and metabolism 2024; (110(1)):78-90 doi:10.1210/clinem/dgae408.

    PMID: 38913686
  8. 8

    Growth hormone deficiency in adults with Cushing's disease.

    Tritos NA

    Best practice & research. Clinical endocrinology & metabolism 2021; (35(2)):101474 doi:10.1016/j.beem.2020.101474.

    PMID: 33272904
  9. 9

    CORRELATION OF INCREASED SERUM ADIPSIN WITH INCREASED CARDIOVASCULAR RISKS IN ADULT PATIENTS WITH GROWTH HORMONE DEFICIENCY.

    Wang Y, Zheng X, Xie X, et al.

    Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists 2019; (25(5)):446-453 doi:10.4158/EP-2018-0541.

    PMID: 30657359
  10. 10

    Impact of Long-Term Growth Hormone Replacement Therapy on Metabolic and Cardiovascular Parameters in Adult Growth Hormone Deficiency: Comparison Between Adult and Elderly Patients.

    Scarano E, Riccio E, Somma T, et al.

    Frontiers in endocrinology 2021; (12()):635983 doi:10.3389/fendo.2021.635983.

    PMID: 33716985
  11. 11

    Bone microarchitecture and volumetric bone density impairment in young male adults with childhood-onset growth hormone deficiency.

    Yang H, Yan K, Yuping X, et al.

    European journal of endocrinology 2019; (180(2)):145-153.

    PMID: 30481154
  12. 12

    3D DXA Hip Differences in Patients with Acromegaly or Adult Growth Hormone Deficiency.

    Gracia-Marco L, Gonzalez-Salvatierra S, Garcia-Martin A, et al.

    Journal of clinical medicine 2021; (10(4)) doi:10.3390/jcm10040657.

    PMID: 33572103
  13. 13

    Growth hormone deficiency during young adulthood and the benefits of growth hormone replacement.

    Ahmid M, Perry CG, Ahmed SF, Shaikh MG

    Endocrine connections 2016; (5(3)):R1-R11 doi:10.1530/EC-16-0024.

    PMID: 27129699
  14. 14

    Individual sensitivity to growth hormone replacement in adults.

    Boguszewski CL

    Reviews in endocrine & metabolic disorders 2021; (22(1)):117-124 doi:10.1007/s11154-020-09605-1.

    PMID: 33026599
  15. 15

    Treatment of Pre-pubertal Patients with Growth Hormone Deficiency: Patterns in Growth Hormone Dosage and Insulin-like Growth Factor-I Z-scores.

    Oberle M, Grimberg A, Bamba V

    Journal of clinical research in pediatric endocrinology 2017; (9(3)):208-215 doi:10.4274/jcrpe.4125.

    PMID: 28150584
  16. 16

    Effect of recombinant human growth hormone plus vitamin D on development and lipid metabolism in children with growth hormone deficiency.

    Zhao J, Miao Y, Ying X, et al.

    Biotechnology & genetic engineering reviews 2024; (40(3)):2960-2970 doi:10.1080/02648725.2023.2202991.

    PMID: 37066983

This page provides informational guidance on transitioning to adult care for IGHD. Always consult your pediatric and adult endocrinologists for personalized re-testing and treatment plans.

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