There are no non-animal sources verified by human trials, therefore it is imperative that vegans and vegetarians supplement with B12
Vitamin B12 is generally very well-tolerated by most individuals
Peptides are typically administered through subcutaneous injections, which can be done conveniently at home after proper instruction, or through other methods like nasal sprays, creams, or tablets, depending on the specific peptide and protocol
Sterile water contains no preservative, so once the stopper is punctured, its susceptible to bacterial contamination
A basic spreadsheet or notebook tracking: daily dose and time, weekly weight, bi-weekly measurements, and subjective notes provides sufficient data without excessive burden
If B12 levels are low but still in range indicating a functional deficiency (this is a deficiency but blood tests appear in normal range) then second line testing of homocysteine and MMA can confirm B12 and/or folate deficiency