Most peptides degrade in the digestive system, making injectable administration standard
Rahman I, Bel A, Mulier B, Lawson MF, Harrison DJ, MacNee W, and Smith CA (1996)
& Apostolopoulos, V
Antibodies specific for p70S6 kinase, phospho-p70S6 kinase (Thr 389), S6 ribosomal protein, phospho-S6 ribosomal protein (Ser 235/236), eIF2, phospho-eIF2 (Ser 51), PERK, Bip and horseradish peroxidase (HRP)-linked secondary antibodies were from Cell Signaling Technology (Danvers, MA, USA)
2006 Jul-Aug;29(7):594-8
B12 is an essential nutrient, and its deficiency is common, especially among individuals following restricted diets like vegetarianism or veganism, pregnant or breastfeeding women, older adults, those who have undergone gastrointestinal surgery or have gastrointestinal disorders, and people with an autoimmune condition known as pernicious anaemia