# What is IGF-1? Insulin-like growth factor 1 (IGF-1) is a hormone that is similar in structure to insulin. It plays a role in normal growth and development, and it is also involved in the regulation of body composition, metabolism, and cell growth. Its levels in the blood can be affected by various factors, including age, diet, and [exercise](../3.%20Treatments/Exercise.md). IGF-1 has been shown to have both pro-tumor and anti-tumor effects, depending on the context. On the one hand, high levels of IGF-1 can promote the growth of certain types of cancer cells, and some studies have suggested that high levels of IGF-1 may be a risk factor for certain types of cancer, such as breast, prostate, and colorectal cancer. On the other hand, low levels of IGF-1 have been linked to poor outcomes in some types of cancer, such as ovarian cancer and non-small cell lung cancer. The relationship between IGF-1 and cancer is complex and not fully understood, and more research is needed to determine the precise role of IGF-1 in the development and progression of cancer. Some studies have suggested that targeting the IGF-1 pathway may be a promising strategy for cancer treatment. # Matt's notes on IGF-1: In addition, IGF-1 seems to inhibit [apoptosis](Apoptosis.md). ([Prisco et al., 1999](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3762887/#R54); [Ramsey et al., 2002](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3762887/#R56)). The reduction in IGF-1 plays a key role in protecting against cancer and slowing aging in mammals ([Colbert et al., 2009](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3762887/#R11); [Hursting et al., 1999](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3762887/#R24); [Sonntag et al., 1999](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3762887/#R68)). #Source: [Short-term calorie and protein restriction provide partial protection from chemotoxicity but do not delay glioma progression - PMC](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3762887/)