vitamin d3 b12 injection D - Cyanocobalamin (Vitamin B12) Injection is sold as an FDA approved generic drug Calcium Vitamin D3 And Vitamin
Description
What is Vitamin B12 good for besides energy

Studies have demonstrated a clear link between low B12 levels and decreased metabolic rate, while B12 injections have been shown to promote weight loss by increasing metabolic rate

signs like rash, itching, or swelling would necessitate immediate medical attention
Both are effective

These figures come from preclinical and pharmacokinetic literature, not from approved human dosing and note the standard route for this molecule is oral