Growth Hormone Therapy: Medical Uses, History, and Safety
Growth hormone (GH) is a protein hormone essential for growth and development. In the field of endocrinology—the study of hormones and the glands that produce them—GH therapy has evolved from a scarce, high-risk resource to a widely available recombinant medication. While primarily used to treat growth deficiencies in children, its application in adults and its role in controversial off-label uses remain subjects of significant medical debate.
Key Facts
- Medical Approval: FDA-approved for GH deficiency in children and adults, and specific conditions like short-stature homeobox gene deficiency.
- Evolution of Treatment: Transitioned from cadaver-extracted GH (1960s–1985) to recombinant human growth hormone (rHGH) to eliminate contamination risks.
- Safety Warning: There is no scientific evidence that GH is safe or effective for healthy adults or geriatric patients to reverse aging.
- CJD Link: Early cadaver-derived GH was linked to Creutzfeldt–Jakob disease (CJD), leading to its total replacement by synthetic versions.
Medical Applications of Growth Hormone
The primary goal of GH therapy is to treat individuals who cannot produce sufficient amounts of the hormone naturally. This is most common in pediatric patients, but adult deficiency is also a recognized medical condition.
Growth Hormone Deficiency in Children
Children with severe GH deficiency often exhibit proportional shortness. Without treatment, they may fail to reach a healthy adult height. The therapy aims to stimulate linear growth during the developmental years.
Growth Hormone Deficiency in Adults
Adults who suffered from GH deficiency as children, or those who develop it later, may experience a decline in quality of life. Symptoms often include reduced physical and mental energy, increased adipose (fat) tissue, diminished muscle mass, lower bone density, and higher cholesterol levels. Clinical trials have shown that GH replacement can improve these parameters.
Idiopathic Short Stature (ISS)
Idiopathic short stature refers to severe unexplained shortness where a child is projected to be below the 3rd percentile of adult height, despite normal test results. This is a controversial indication. In trials sponsored by Eli Lilly for their brand Humatrope, children at least 2.25 standard deviations below the mean gained 4–8 cm in adult height over four years. However, some experts argue whether these children are truly diseased or simply at the extreme end of the normal height range.
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The History and Evolution of GH Therapy
The history of GH therapy is marked by a shift from biological extraction to genetic engineering.
The Era of Cadaver Growth Hormone
From the late 1950s to the late 1980s, GH was extracted from the pituitary glands of human cadavers. In the U.S., this was managed by the National Pituitary Agency (NPA). Because supplies were limited, the hormone was strictly rationed, often stopped once a child reached a minimal height (such as 5 ft 0 in).
The CJD Crisis and the Rise of rHGH
In 1985, it was discovered that some patients treated with cadaver GH had developed Creutzfeldt–Jakob disease (CJD), a rare and fatal brain disorder. Between 1985 and 2003, 26 cases were identified among 7,700 U.S. recipients. This led to the immediate cessation of cadaver GH and the FDA approval of recombinant human growth hormone (rHGH), such as Protropin, which is produced via bacterial synthesis and carries no risk of CJD.
| Feature | Cadaver GH (1960-1985) | Recombinant GH (rHGH) |
|---|---|---|
| Source | Human pituitary glands | Bacterial production |
| Availability | Very limited (Rationed) | Abundant |
| Primary Risk | Creutzfeldt–Jakob disease (CJD) | High cost / Off-label misuse |
| Consistency | Variable | Standardized |
Safety, Adverse Effects, and Misconceptions
As rHGH became more available, its use expanded beyond approved medical indications, leading to concerns from the medical community.
Off-Label Use and Anti-Aging Claims
The New England Journal of Medicine has expressed concern over the proliferation of "HGH-Releasing" supplements and claims that GH can reverse aging. Experts emphasize that there is no evidence that GH is safe or effective for healthy adults or geriatric patients, and the long-term risks of such use remain unknown.
Cancer Risks
There has been historical concern that GH treatment could increase cancer risk. However, a large study of 6,840 adults receiving GH found that the overall primary cancer risk was not increased, although elevated risks were noted in specific subgroups, such as those under age 35 or those with childhood-onset deficiency.
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Frequently Asked Questions
What is the difference between cadaver GH and rHGH?
Cadaver GH was extracted from human pituitary glands and carried a risk of transmitting CJD. rHGH is a synthetic version produced using recombinant DNA technology, making it safer and more readily available.
Can growth hormone be used to reverse aging in healthy adults?
No. There is no scientific evidence to support the claim that GH therapy is safe or effective for reversing aging in healthy adults or geriatric patients.
What is idiopathic short stature (ISS)?
ISS is a condition where a child is severely short without a clear medical cause or deficiency. Its use as a reason for GH therapy is controversial among pediatric endocrinologists.
Are there cancer risks associated with GH therapy?
While general studies of adults receiving GH have not shown an overall increase in primary cancer risk, some specific subgroups (such as those under 35) may show elevated risks.
Why was cadaver GH withdrawn from the market?
It was withdrawn in 1985 after it was discovered that the hormone was contaminated with agents causing Creutzfeldt–Jakob disease (CJD).