Insulin-like growth factor 1 (IGF1) is a natural hormone the body produces. It contains seventy amino acid polypeptides that are produced by the liver and endocrine hormone system. IGF-1 also plays a role in cell repair to the muscles, brain and heart.
Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a hormone similar in molecular structure to insulin. It plays an important role in childhood growth and continues to have anabolic effects in adults.
IGF-1 is produced primarily by the liver as an endocrine hormone as well as in target tissues in a paracrine/autocrine fashion. Production is stimulated by growth hormone (GH) and can be dysfunctional due to under nutrition, growth hormone insensitivity and lack of growth hormone receptors. Approximately 98% of IGF-1 is always bound to one of 6 binding proteins (IGF-BP).
IGFBP-3, the most abundant protein, accounts for 80% of all IGF binding. IGF-1 binds to IGFBP-3 in a 1:1 molar ratio.
IGF-1 is a primary mediator of the effects of growth hormone (GH). Growth hormone is made in the anterior pituitary gland, released into the blood stream and then stimulates the liver to produce IGF-1. IGF-1 then stimulates systemic body growth and has growth-promoting effects on almost every cell in the body especially skeletal muscle, cartilage, bone, liver, kidney, nerves, skin and lungs. In addition to the insulin-like effects, IGF-1 can also regulate cell growth and development especially in nerve cells as well as cellular DNA synthesis.
- Chronic fatigue
- Lack of stamina
- Sexual dysfunction
- Loss of muscle tone
Frater J, Lie D, Bartlett P, McGrath JJ. Insulin-like Growth Factor 1 (IGF-1) as a marker of cognitive decline in normal ageing: A review. Ageing Res Rev. 2018;42:14‐27. doi:10.1016/j.arr.2017.12.002
Nicholls AR, Holt RI. Growth Hormone and Insulin-Like Growth Factor-1. Front Horm Res. 2016;47:101‐114. doi:10.1159/000445173