where to inject b12 in leg How self-inject intramuscular vitamin - Overview Choosing the Right Needle and

K.SwaminathanS.et al (2018)

If youre unsure whether you still need to take a pre- or postnatal supplement or you have specific questions about how long you should continue taking it, consult a healthcare professional

Assuming more is always better serum B12 above 1,000 pg/mL from supplementation is generally harmless, but persistently high B12 without supplementation warrants investigation for liver disease or myeloproliferative disorders [7]

TB-500s long half-life means timing within the day matters little

However, if you are taking vitamin B12 because you think it will cure your joint pain, then you may not experience the results you're hoping for