Human Growth Hormone (hGH) is also known as Growth Hormone (GH) or Somatotropin. Growth hormone is responsible for maintaining lean body mass, organ growth, reducing fat mass in adults (lipolysis), enhancing exercise endurance and improving oxygen uptake. The use of exogenous HGH has a variety of physiological properties that are beneficial for the adult male. hGH is produced and released by the anterior pituitary gland and is under direct control of Growth Hormone Releasing Hormone (GHRH) and Somatostatin (GH inhibiting hormone). In the human body, hGH is released into circulation in a pulsatile fashion approximately every 90-120 minutes and with greater frequency of release during sleep. HGH levels are highest during puberty and slowly decline as men age. hGH activity is assessed by measuring insulin like growth factor (IGF-1). Because of the beneficial anabolic effects of hGH, adult males have utilized hGH replacement to replenish hGH levels that naturally decrease with age. In men who have low hGH levels, replacement can improve bone mineral density, muscle strength and size, promote fat loss, increase lean body mass, enhance immune function, quality of life, exercise tolerance and have effects on skin tone While many of these androgenic effects of hGH have are attractive to men, the use of hGH is restricted by the FDA to a few medically necessary conditions and include: 1. HGH deficiency in childhood 2. Hypopituitarism 3. AIDS wasting syndrome 4. Short bowel syndrome Alternative and safer therapies have been developed to increase the body’s natural secretion of hGH in men who have hGH deficiency. Growth hormone secretagogues are an alternative therapy to exogenous growth hormone replacement, that can improve hGH levels safely.

There are two signalizing hormones called Growth Hormone Releasing Hormone (GHRH) and Ghrelin that stimulate hGH release from the pituitary gland. GHRH is released by the hypothalamus and ghrelin is released by the small intestine and stomach. Ibutamoren mesylate is a medication that stimulates ghrelin receptors located in the stomach and small intestine to signal natural hGH release in men who have growth hormone deficiency.

Human growth hormone levels decrease as a man ages. The most common cause for a deficiency of human growth hormone is from a pituitary adenoma treated with surgery or radiotherapy. Predicting growth hormone deficiency (GHD) can be made by measuring IGF-1 levels. The gold standard to confirm (GHD) is an insulin tolerance test (ITT).

The signs and symptoms of adult’s males with growth hormone deficiency include: • Obesity • Altered body composition (abnormal fat deposition) • Reduced lean body mass • Reduce strength • Fragility • Increased fat mass • Reduced total body water • Reduced cardiac performance and function • Reduced physical performance and endurance • Abnormal lipid parameters • Reduced well-being and quality of life (QOL) Benefits of GH-elevation in patients with GH-Deficiency: • Restoration of lean body mass • Improvement in fat deposition • Improvement in plasma lipid profile • Enhanced exercise capacity • Efficient protein synthesis for muscle growth • Eeduce frailty • Emprovement in quality of life (QOL) • Increase total body water content

Growth hormone secretagogues also called growth hormone releasing peptides (GHRPs) are peptides that stimulate the body’s natural release of growth hormone. GHRPs are composed of 6 amino acids that stimulate natural growth hormone release without affecting other pituitary hormones or receptors. Unlike exogenous hGH, growth hormone releasing peptides have a lower side effect profile and can still produce many of the benefits of exogenous hGH administration in men with growth hormone deficiency. Growth hormone secretagogues may offer an advantage, promoting the natural and pulsatile release of hGH compared to exogenous hGH administration. Examples of growth hormone secretagogue include Imbutamoren Meyslate and GHRP-6 (Hexarelin).

Growth Hormone Releasing Peptides are a type of Growth Hormone Secretagogue and were first synthesized in 1977 to stimulate natural Growth Hormone (GH) release from the anterior pituitary. The first Growth Hormone Release Peptide with significant in-vivo activity was GHRP-6. GHRP-6 mimics the activity of Growth Hormone Releasing Hormone (GHRH) to stimulate the pituitary to release GH. GHRP-6 has a very short half-life of only 20 minutes and has the benefits of restoring GH secretion and improving sleep. Other GHRPs include GHRP-2 and Sermorelin.

IGF-1 is short for insulin like growth factor. IGF-1 is a hormone that mediates human growth hormone activity. The majority of IGF-1 is secreted by the liver and regulated by nutrient intake, growth hormone, thyroid hormone, cortisol and among other hormones. IGF-1 is an important growth hormone that has both anabolic and linear growth promoting properties. IGF-1 is necessary for physiological growth hormone production and exerting growth hormone like effects on target tissues and organs.

IGF-1 is measured to assess the activity Human Growth Hormone (hGH). While IGF-1 levels are dependent on a variety of other factors that include nutritional status, muscle mass, body fat, thyroid hormone levels and growth hormone levels, IGF-1 is a good screening tool for growth hormone deficiency. IGF-1 levels are useful to assess human growth hormone excess and/or response to therapy.

Testosterone stimulates the pulsatile release of human growth hormone (HGH) from the anterior pituitary and increases insulin like growth factor (IGF-1) concentrations in the body. IGF-1 is also known inhibit sex hormone binding globulin (SHBG) thereby increasing free and available testosterone. Testosterone stimulates muscle growth by promoting the fusion of human skeletal muscle cells into larger myotubules. IGF-1 is present in muscle tissue and is partially responsible for the increase in growth and fusion of skeletal muscle cells to form larger muscle tissue. IGF-1 and testosterone have an integral role in skeletal muscle tissue growth and enlargement.

Human Growth Hormone (hGH) is a hormone the body natural secretes from the anterior pituitary gland to stimulate bone growth, promote lean body mass, reduce fat mass, maintain organ size, regularte glucose and lipid metabolsm and maintain other roles in human physiology and bodily functions. In 1985 synthetic hGH was developed and approved by the FDA for very specific and narrowly defined medical indications. There are two forms of synthetic hGH: Somatropin and Somatrem. Somatropin is similar and identical in molecular structure to the naturally produced hGH from the anterior pituitary. Somatrem has an additional amino-acid, but is otherwise similar to endogenous pituitary derived hGH. The use of hGH can have several adverse side effects including fluid retention, edema, carpal tunnel syndrome, muscle pain, abnormal skin sensation and possible exacerbation of pre-existing malignancy. Several FDA approved injectable preparations of synthetic hGH exist and include: Genotropin ®, Humatrope ®, Norditropin ®, Nutropin ®, Saizen ®, Serostim ®. Synthetic hGH preparations are approved by the FDA for a diagnosed medical condition and require a supervising physician. In adult males, synthetic hGH use is approved for wasting syndrome of AIDS and hGH deficiency. A growth hormone secretagogue is a medication, available only by a prescription, that stimulates the body to release natural HGH. A growth hormone secretagogue is not a synthetic form of hGH, but rather a medication that stimulates the body to release its own supply of hGH. This mechanism of actions can provide a more physiological release of hGH and maintain hGH levels within a safe parameter while improving the sings and symptoms of growth hormone deficiency in men.

Sermorelin, also known as a growth hormone releasing factor 1-29NH2- Acetate, is a an analogue to growth hormone releasing hormone (GHRH). Sermorelin is administered as a subcutaneous injection nightly. Sermorelin stimulates a patient’s own pituitary gland to release endogenous hGH. The advantages of Sermorelin compared to exogenous hGH administration are the following: 1.Sermorelin stimulates endogenous hGH release and is still under the negative feedback control of somatostatin. Compared to exogenous hGH in which over dosing is possible, Sermorelin is a safer alternative given there is a finite amount of hGH that body can release at any one time. 2. With Sermorelin administration, hGH maintains a normal physiological pulsatile release that is episodic and intermittent compared to exogenous hGH which is constant. 3.Tachphylaxis often observed with exogenous hGH administration is avoided.

Wasting syndrome is the unwanted loss of more than 10 percent of a man’s body weight. Wasting syndrome can occur from a variety of conditions that include, but not limited to, advanced HIV disease, inflammation, infection or aging. Growth hormone secretagogues can be an effective treatment to reverse wasting conditions and improve strength, muscle size, maintain lean body mass, improve proper fat deposition in patients with lypodystrophy and improve frailty.