Administration Technique: For injectable forms, proper subcutaneous injection technique, site rotation, and sterile handling minimize the risk of injection site reactions or infections
Slim Down and Boost Your Metabolism With B12 Injections
However, infants of vitamin B 12 -deficient breastfeeding mothers are vulnerable to B 12 deficiency from an early age.19 Maternal vitamin B 12 deficiency has been associated with increased risk of common pregnancy complications, including spontaneous abortion, low birth weight, intrauterine growth restriction and neural tube defects.2022 Children born to vitamin B 12 -deficient women are at increased risk for adverse health outcomes, including developmental abnormalities and anaemia.9 23 In a recent RCT in Bangalore, India, daily maternal vitamin B 12 supplementation (50 g/day) during pregnancy through 6 weeks postpartum substantially improved maternal vitamin B 12 status and increased breast milk and infant plasma vitamin B 12 concentrations.24 In this study, the proportion of children being born small for gestational age was lower in the vitamin B 12 group than in the placebo group (25% vs 34%)

The theory is that gradual dose reduction gives the body time to recalibrate appetite and metabolic signaling, rather than experiencing a sudden return to pre-treatment hunger levels
Annu Rev Biochem 73 , 10191049, (2004)
There is no proven human timeline