Immune cells, like other body cells, have receptors of IGF and can be enhanced by HGH.
◦ T-cells. This type of cells is produced by the thymus and is responsible for most of the immune system functions. With age, thymus atrophies and its function worsen. However, studies have found that HGH returns the thymus its size and revives its functions. Scientists have proved that people with growth hormone deficiency have problems with the thymus, but they can be resolved if the patient takes exogenous HGH.
◦ NK-cells (natural killer cells).
Natural killer cells that complement T-cells can also be stimulated by HGH. This function remains active even after GH treatment ends.
Growth hormone can augment immunoglobulin production, thus stimulating B-cells to resist illnesses by secreting antibodies. Expanding life period of cells This HGH benefit allows to make a cell younger and slower the aging process. It has made growth hormone a popular drug in the anti-aging therapy. Growth hormone prevents a rapid death of a cell as it doesn’t allow telomerase (a cell’s life cycle) to shorten. As a result, the cell lives longer.
Other Benefits of HGH:
◦ HGH diminishes the level of cholesterol. The research by Johan Verhelst and Roger Abs  has shown that growth hormone decreases the total level of cholesterol by 7%. The scientists noticed the especial decrease in the level of bad cholesterol of very low density (VLDC). ◦ Improves sleep. Growth hormone improves the quality of sleep. People who take HGH say that they sleep like babies. It results in the better muscular and nervous recovery.
◦ Improves skin. Due to the synthesis of elastin and collagen, HGH makes skin cleaner and more elastic. It also helps smooth age wrinkles and hydrates dehydrated skin in the elderly.
◦ Improves the cardiovascular function. Numerous studies on GH-deficient people have shown that they have significantly higher risk of heart failure and other cardiovascular diseases. People with GHD have bad lipid profiles, high level of cholesterol, the increased amount of fat concentrated in the abdominal area, etc.
The experiment on rats performed by Renhui Yang  has shown that GH helps fight heart diseases and prevent the occurrence of new ones. One of the reasons is that it increases the cardiac index (the ability of the heart to pump blood well), stroke volume index (the heart’s capacity to excrete blood), and left ventricular maximum (it shows the strength of the heart).
Mental Benefits of Growth Hormone:
◦ GH improves visual perception.
◦ Strengthens muscles that control accommodation for viewing objects.
◦ Prevents retinal degeneration.
◦ Prevents cataract and glaucoma
◦ Improves memory and the cognitive function
Michael Vitiello and Baker LD  have conducted experiments to evaluate how the increased level of HGH improves cognitive functions, particularly the executive function, IQ, and memory.
After ten weeks of treatment, the results showed the significant improvement in the executive function (ability to concentrate, think quickly, remember information connected with usual life), ability to memorize and solve intellectual tasks (IQ rise).
1) D J O’Halloran, A Tsatsoulis, R W Whitehouse – Increased bone density after recombinant human growth hormone (GH) therapy in adults with isolated GH deficiency
2) Agnieszka M. Lichanska, Michael J. Waters – How growth hormone controls growth, obesity and sexual dimorphism
3) Franco Antoniazzi, MD Francesco Bertoldo, MD Monica Mottes, PhD – Growth hormone treatment in osteogenesis imperfecta with quantitative defect of type I collagen synthesis
4) Banks WA1, Morley JE, Farr SA – Effects of a growth hormone-releasing hormone antagonist on telomerase activity, oxidative stress, longevity, and aging in mice.
5) Growth Hormone to Increase Immune Function in People With HIV
6) Verrillo E1, Bizzarri C, Bruni O – Effects of replacement therapy on sleep architecture in children with growth hormone deficiency.
7) CP Velloso – Regulation of muscle mass by growth hormone and IGF-I
8) Philipp Dreifuss, MD – Cardiac Effects of Growth Hormone
9) Renhui Yang, MD; Stuart Bunting, PhD; Nancy Gillett, – Growth Hormone Improves Cardiac Performance in Experimental Heart Failure 10) Dr. Laura D. Baker, PhD, Ms. Suzanne M. Barsness – Effects of Growth Hormone–Releasing Hormone on Cognitive Function in Adults With Mild Cognitive Impairment and Healthy Older Adults
11) Fitzgerald, Susan – Can a Growth Hormone-Stimulating Drug Improve Cognitive Function?
12) Dr Ben Green MRCPsych FHEA – Human Growth Hormone In The Treatment Of Biological Depression
13) Michael V. Vitiello, PhD,* Robert S. Schwartz, MD, Karen E. Moe – Growth hormone releasing hormone improves the cognition of healthy older adults
14) Niels Møller and Jens Otto Lunde Jørgensen – Effects of Growth Hormone on Glucose, Lipid, and Protein Metabolism in Human Subjects
15) Dr. Daniel Rudman – HGH Injection Study in the New England Journal of Medicine 16) Johan Verhelst and Roger Abs – Cardiovascular risk factors in hypopituitary GH-deficient adults