what is in the b12 injection What's all Buzz About Vitamin B12 Shots? Vitamin B12 Injections for Energy,

1 Aged Muscle Stem Cell Rejuvenation Neelakantan et al., Biochemical Pharmacology (2019) In a follow-up study, the authors tested whether NNMT inhibition could reverse the age-related decline in muscle stem cell (satellite cell) function

If you're deficient in B12, injections can increase your energy and well-being (which may lead to weight loss)

Medications know to cause bone marrow suppression (e.g., myelosuppressive antineoplastic agents) may result in a blunted or impeded response to methylcobalamin, vitamin B12 therapy

Unless the body is deficient, B12 injections are unlikely to increase energy levels or improve performance