Peptide therapy uses targeted amino-acid sequences that mimic or influence natural hormones and growth factors in the body, delivered most often by subcutaneous injections, occasionally by oral or other routes depending on the molecule
References Raun K, Hansen BS, Johansen NL, Thgersen H, Madsen K, Ankersen M, Andersen PH
This portability enhances the ease treatment and research regimens, as subjects can conveniently carry their pens and administer peptides without disrupting daily activities
For more on how long reconstituted peptides last in the fridge across different types, and details on peptide expiration in general , these resources cover stability science in depth
In other words, if you are not deficient, adding more B12 does not create an effect, because your body already has what it needs and excretes the excess