Methionine is a sulfur-containing amino acid that improves skin elasticity and strengthens hair and nails (PubChem, 2020)
At a MAHA summit held in Washington, D.C., last November, panelist Josh Fritzler, an executive at two affiliated compounding pharmacies based in Florida, said his grandmother is taking BPC-157
If the injection is needed (e.g., to replete B or B in a deficient mother), it can be used, but the infant should be observed for any unusual symptoms (though none would be expected from B vitamins, apart from perhaps looser stools if anything)
This form of B12 is the one most commonly found in prescribed injections, although you may find it in other high strength oral supplements
Of course, all three causes can also work in combination
Refrigeration is not strictly required by the USP standard