Amino Acids May Feed Cancer Cells, Not Patients.

In 2025, Giovanni Corsetti and a team from the University of Brescia reviewed studies on amino acid (AA) supplements in cancer patients. They looked at how diet and obesity cause up to 50% of tumors, and how 30-90% of patients get malnutrition from the tumor's high energy use, leading to muscle loss and weakness called sarcopenia or cachexia.

The findings showed tumors steal AAs from the body to grow, and supplements might help the cancer more than the patient. Essential AAs like leucine boost tumor signals (mTOR pathway up 20-30%), speeding growth, while non-essential AAs like glutamine fuel cancer cells (up to 40% of their energy). High doses in animals raised tumor size by 15-25%.

Talk to your doctor before taking AA supplements if you have cancer—they may do more harm than good.