b12 injection make you sleepy From Fatigue to Fabulous: How Injections Can Revitalize Your Energy and Wellness B12 Shots Side Effects And
Description
Just like cyanocobalamin, it has to be reduced from state +3 to +1 before it can become either methyl B12 or adenosyl B12

Biochemical Journal , 467(2), 289301

Pre-Injection Preparation Wash your hands well with soap and water
Can I continue this medication if Im planning to become pregnant