While B12 can be taken orally, injections or IVs are really the most effective, absorbable ways to get B12 into your system

WATER, BUTYLENE GLYCOL, PROPANEDIOL, GLYCERIN, CAPRYLIC/CAPRIC TRIGLYCERIDE, NIACINAMIDE, VINYL DIMETHICONE, 1,2-HEXANEDIOL, SQUALANE, POLYGLYCERYL-10 LAURATE, SODIUM POLYACRYLOYLDIMETHYL TAURATE, CETEARYL OLIVATE, SORBITAN OLIVATE, ETHYLHEXYLGLYCERIN, DIMETHICONOL, CARBOMER, TROMETHAMINE, GLUTATHIONE, HYDROLYZED SPONGE, TOCOPHEROL, ASPARAGUS OFFICINALIS EXTRACT, XANTHAN GUM, ADENOSINE, CITRUS AURANTIUM DULCIS (ORANGE) FLOWER OIL, LITSEA CUBEBA FRUIT OIL, DISODIUM EDTA, CITRUS PARADISI (GRAPEFRUIT) PEEL OIL, CITRUS AURANTIUM BERGAMIA (BERGAMOT) FRUIT OIL, MENTHA VIRIDIS (SPEARMINT) LEAF OIL, BAROSMA BETULINA LEAF EXTRACT, SORBITOL, ASCORBIC ACID, HELIANTHUS ANNUUS (SUNFLOWER) SEED OIL, SUCROSE STEARATE, GLYCERYL STEARATE, BETA-CAROTENE, FERULIC ACID, (-)-ALPHA-BISABOLOL, BETA-GLUCAN, HESPERIDIN, ERGOTHIONEINE, LIMONENE, LINALOOL, CITRAL *** Ingredients are subject to change at the manufacturer's discretion

doi: 10.1146/annurev-biochem-061516-044932 67 CelliASanchezSBehneMHazlettTGrattonEMauroT
doi: 10.1039/c1dt11785h
In general, about 29 gut microbiota taxa are different in GDs compared with HCs