is oral replacement better than injectable b12 Vitamin Injections vs. Supplements: Which Better? B12 Injections vs Pills: Richmond's
Description
The effects last about 24-72 hours, depending on your metabolism and vitamin stores

doi:10.1136/bmjopen-2020-041290

Vit B12 only occurs in animal products and vegans have to take supplements

These signs may indicate degradation or contamination
