The half-life of HGH is approximately 14 minutes. In between pulses, serum growth hormone is minimal or undetectable. Generally, growth hormone pulses occur approximately 10 times per day, lasting 90 minutes in length, and are separated by 128-minute intervals.[i]
Although it is typical in the US to suggest and require growth hormone to only be assessed in 24-hour sampling intervals for determining growth hormone deficiency and/or pituitary dysfunction, IGF-1 has been used successfully in various research for many years to assess HGH deficiency and optimization. The benefit of using IGF-1 is two-fold: 1) it is a safer and easier to test it with a blood test, and 2) IGF-1 is directly proportional to HGH production and is more stable, making it a good marker of measurement.
Human growth hormone decline is estimated to be around 50% every seven years in aging adults. This is dependent on a variety of factors. Many unique environmental influences related to one’s lifestyle can determine the quality of one’s human growth hormone secretion. Some of the more common factors are:
Promoters of Growth Hormone Secretion
Nutritional Factors – HGH Stimulators
Sex Steroids – HGH Stimulators
Growth hormone is needed to control the tempo and progression of puberty in young boys. There is evidence of rising serum androgen concentrations and peak amplitude of human growth hormone in pubertal boys.[iv] Sex hormones can act centrally by regulating HGH secretion and peripherally by regulating HGH responsiveness. Sex hormones modulate HGH secretion directly and indirectly through IGF-1 modulation.[v]
GHRH – HGH Stimulators
The most well-known regulator is growth hormone releasing hormone GHRH. It is a 44 amino acid peptide hormone produced in the hypothalamus. The primary function of GHRH is to stimulate the release of human growth hormone in the body. GHRH is released from neurosecretory nerve terminals and is carried through the hypothalamos portal system to the anterior pituitary gland where it stimulates growth hormone secretion. IGF-1 is a down-path hormone produced in the liver and other organs in response to growth hormone activity. IGF-1, along with HGH, work to cause metabolic and growth activities in the body.
Control of GHRH works similarly in the body to a thermostat system on an air-conditioner or furnace for temperature control. Stimulators marked in green in the chart stimulate, while inhibitors marked in “red” work to limit growth hormone secretion. As one side gets lower, the other side gets higher until balance or homeostasis occurs.
In many individuals, levels may not be optimal. This is potentially due to health status and age-related factors. Because of the obesity epidemic (70% overweight/obese) in the United States, growth hormone secretion is very often less than optimal. Other hormones such as testosterone and estrogens are influenced to a much greater degree by environmental and lifestyle factors than once believed. New evidence is showing hormone regulation is disrupted due to these factors. For one such example, see Testosterone Decline in Men – News <Click here>.
This content was originally published here.