If you’ve ever looked into fasting while reading about breast cancer, you’ve probably seen this term pop up again and again: IGF-1. It might feel complicated at first, but IGF is what your body makes on its own. It is a hormone that helps cells grow, repair, and stay active.
IGF-1 is the short form of Insulin-like Growth Factor 1. Most of it is made in the liver and then released into the bloodstream. It does its job in the background by helping with growth, healing, and keeping tissues working properly. You don’t notice it, but your body relies on it. Scientists have been studying it for years because it sits right in the middle of how cells grow and survive. That’s also why it keeps coming up in breast cancer research papers and discussions.
Why IGF-1 Gets Attention in Breast Cancer Research
Breast cancer develops when cells start to grow out of control. Scientists have examined whether increased IGF-1 could affect breast cancer risk, given its role in growth control. Several studies have reported a link between IGF-1 levels and an increased risk of hormone receptor-positive breast cancer, especially after menopause. However, IGF-1 is not the sole cause of breast cancer. But it involves genetics, hormones, family history, body weight, and lifestyle. As per a study published in 2025 by Standidos publication, IGF-1 triggers interconnected survival networks like the PI3K/AKT/mTOR and MAPK pathways, which drive aggressive cancer cell growth.
How Fasting Affects IGF-1 Levels
Fasting can temporarily lower insulin and IGF-1 levels in the body. This simple change is what led researchers to explore whether these short-term shifts could have any impact on how cancer cells grow and behave. IGF-1 levels do drop during fasting or fasting-mimicking diets. But most of what we know so far comes from early-stage research, things like lab studies, animal experiments, and a small number of human trials. That's why the overall understanding is still limited. Right now, there isn’t enough strong human evidence to draw clear conclusions.
Understand this
Breast cancer cannot be treated or cured through diet alone. No eating pattern has been proven to cure it. During cancer treatment, the body is already going through a lot. There can be fatigue, weight loss, poor appetite, and nutrient gaps. In that condition, fasting or strict dietary changes can sometimes add more strain instead of helping recovery. That’s why it’s always better to speak with a doctor or oncology dietitian before making any changes to food habits during treatment.
IGF-1 is simply a hormone in the body that researchers are still trying to understand in the context of breast cancer. It is only one small part of a much larger biological process, and science is still working on how all these factors connect in real life. IGF-1 levels actually mean for a breast cancer patient in real life. The research is still ongoing.