L Glutathione injectable, 30mL Defy Medical Intramuscular vs Subcutaneous injections what's the difference? At KDR, we often use peptides and wellness injections like NAD, glutathione, and HCG, but they are not all administered the same way. Intramuscular injections ( Glutathione IV push 1000mg Dose FDA highlights concerns with using dietary ingredient glutathione to compound sterile injectables FDA