Growth Hormone (GH) secretion and the level of a major product of growth hormone in our blood, IGF-1, decline 14% per
decade of life. By the age of 40 or 50, many people have low IGF-1 levels (<120mcg/dL)--equal to people who have damaged pituitary glands and no GH production at all. Growth hormone stimulates cell division, cell growth, and protein production throughout the body, helping to maintain all tissues. Many studies have shown sufficient growth hormone is essential to the maintenance of our nervous system, immune system, bones, metabolism, and muscles. Higher, rather than lower IGF-1 levels within the reference ranges reduce abdominal fat, blood sugar, and blood pressure. GH replacement in when needed improves mood, energy, sleep quality, and sociability.
Growth hormone cannot be directly measured in the blood because it's produced only during the night while we are in deep
sleep. However, the average amount of growth hormone secretion is reflected in the IGF-1 level in the blood. It is a reliable test: only liver disease or a rare genetic defect can cause a low IGF-1 level in the face of adequate growth hormone secretion. Some medical authorities are now trying to restrict adult GH replacement to those extreme cases where persons have obvious physical damage to their pituitary gland and cannot make any GH even when forced to do so with superphysiological stimuli like insulin or arginine stimulation tests. This policy is unscientific, as a "normal" response to such tests does not guarantee that enough GH is actually being secreted on a daily basis. The best indicator of actual GH secretion under normal circumstances in any person is the IGF-1 level.
Growth hormone restoration, like testosterone restoration, is controversial today partly because athletes are using and abusing it for performance gains, and because most of the early studies of GH replacement in older adults used grossly excessive doses that produced elevated blood sugar, fluid retention, and aching joints. By definition, until proven otherwise, restoring any hormone to young-adult levels is beneficial. Hormones don't have "side effects", they only have effects!
If a person has symptoms of GH deficiency and low IGF-1 levels, Dr. Lindner first tries to improve GH secretion and IGF-1 levels by restoring other hormones (thyroid, testosterone, DHEA, estradiol). Often this works quite well. He will prescribe GH to those with persistent signs and symptoms of GH deficiency and low IGF-1 levels. He uses low, physiologic doses that have been shown to produce benefits without causing signs or symptoms of excess. Unfortunately, GH is not covered by insurance, is expensive (a low-moderate dose costs $250/mo), and requires nightly self-injections.
