Growth hormone (GH) replacement therapy involves getting injections of synthetic human growth hormone to replace the GH that the pituitary gland normally produces. It is primarily used to treat adults with legitimately diagnosed growth hormone deficiency (GHD) to improve symptoms and quality of life.
There is an important distinction between treating diagnosed GHD in adults versus using GH as an "anti-aging" therapy or performance enhancer in healthy people. Reputable endocrinologists caution against the latter unapproved uses which can risk side effects.
For adults with diagnosed GHD, ongoing GH therapy is often necessary. The deficiency is typically caused by damage to the pituitary gland or hypothalamus, rather than being a temporary condition. Therefore, lifelong hormone replacement helps maintain normal metabolism, body composition, bone strength, cardiovascular function, and general wellbeing that would otherwise decline.
- Benefits of continuing GH therapy for deficiency include:
- Maintaining energy levels, muscle mass and bone density
- Reducing cardiovascular risk factors
- Improving cholesterol levels
- Enhancing quality of life and ability to handle stress
- Risks of stopping therapy can include:
- Fatigue, low energy and endurance
- Loss of muscle strength
- Increased body fat, especially abdominal fat
- Higher LDL cholesterol and triglycerides
- Impaired cardiac function
- Greater fracture risk from osteoporosis
The required dose of GH for an adult with GHD is highly individualized and begins with a very low dose that is progressively adjusted based on lab work, documented deficiency symptoms, and monitoring for side effects under a doctor’s care. Blood tests check insulin-like growth factor 1 (IGF-1) levels, which give feedback on the biological GH activity in that person’s body. The goal is to titrate supplementation just high enough to bring their IGF-1 into the middle part of normal range.
- Too low of a GH dose may not adequately relieve deficiency symptoms
- Excessively high GH can accelerate growth of any preexisting cancer cells and cause hyperglycemia, fluid retention, joint pain and other unnecessary adverse effects
Therefore, adults needing GH therapy for deficiency should plan to stay under the care of an endocrinologist for ongoing dose adjustments and lab monitoring. How frequently this is needed varies per patient but tends to be 1-4 times per year after the initial titration period.
- Some adults are able to gradually decrease their maintenance GH dose with age, as the natural decline in their baseline IGF-1 levels means less exogenous supplementation is needed to reach middle-normal range. But complete cessation of therapy should only be considered when IGF-1 stabilizes well within normal limits even without GH injections. This situation is relatively uncommon.
- More commonly some degree of ongoing treatment continues to be necessary even into later decades of life. The physician monitors labs and symptoms and individualizes dosage accordingly within safe therapeutic range.
In summary,
growth hormone replacement for deficiency in adults is highly customized to the person's changing needs. While not always lifelong, it frequently is long-term or permanent to maintain health and quality of life. Close medical supervision is important throughout treatment to ensure appropriate GH dosing through the years.