The Glutathione and Vitamin D Relationship GrassrootsHealth Glutathione IV Therapy: What You Need to Know C peptide is a biomarker for beta cell function. In other words, it's a measure of beta cell health and insulin production, and is critical to developing new disease modifying therapies for type 1 Glutathione system enhancement for cardiac protection: pharmacological options against oxidative stress and ferroptosis Cell Death & Disease