mthfr gene and glutathione – Methyl-Life® Supplements Understanding MTHFR genetic variation and
Description
The frequency of the vitamin B12 injections depends solely on the individuals health needs, such as age, underlying cause of malabsorption, dietary habits, medication and most importantly, response to the injection
No complicated routine

You and your doc will need to consider both options based on your unique situation

B12 shots have also been used to enhance athletic performance and treat heart disease, osteoporosis, and anemia

PMID 21428697

[32] There is no restriction on its availability in United States, Philippines and Japan