A B12 injection can help replenish the body's B12 levels in such cases directly and efficiently
It does not tell you what to inject, what dose to use, or how to treat anything
R&D Investor Presentation (2020)
Mechanisms and consequences Non-injectable B12 products that do not require gastric acidity and/or Intrinsic Factor (IF) are now available to support B12 absorption
It contains a DExD/H-box RNA helicase domain and a C-terminal domain (CTD) that bind dsRNA, along with two N-terminal caspase activation and recruitment domains (CARDs) that interact with the mitochondrial antiviral signaling protein (MAVS) to induce transcription of type I IFNs and downstream IFN-stimulated genes (ISGs) (99, 103)
A product specifically formulated to include both actives in a stable, pH-balanced system with appropriate attention to chelation, emulsion type, and antioxidant systems is a meaningfully different situation from ad-hoc layering of two separate products