Choosing the Right Form For most people supplementing orally, methylcobalamin or a methylcobalamin/adenosylcobalamin combination is the best choice
This makes compounded BPC 157 products (including nasal sprays) legally problematic for licensed pharmacies in the United States
The reality is that that what the FDA means by safety is a matter of regulatory compliance (large scale clinical trials, manufacturing standards, etc.) not toxicity
High dosages can get you mild side effects like diarrhea, nausea, dizziness, headaches, or a very warm burning feeling in the injection area
There is no robust clinical evidence that B12 injections enhance energy, alertness, or performance in individuals whose B12 levels are already adequate