Subcutaneous Injection: What It Is and How to Give One 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 Injection Faces By Bae Why Is Glutathione Added as a Push? Glutathione IV Power Subcutaneous Injection: What It Is and How to Give One