b12 injections im or sq Best Vitamin Injection Site: Administering B12 Shots How to self-inject intramuscular vitamin

Nat Metab 3 , 14451465 (2021)

it's a potent non-stimulant small molecule that selectively inhibits Nicotinamide N-methyltransferase (NNMT), an enzyme primarily found in adipose tissue and the liver

Our observation that intracellular NA concentrations did not increase following NNMT inhibition extends previous studies that showed NA concentrations were largely unaffected following NNMT knockdown with either adenovirus[39] or anti-sense oligonucleotides (ASOs).[12] It is possible that significant accumulation of NA in adipocytes (and other tissues) is prevented by rapid conversion of NA to NMN and subsequent NAD + synthesis or transport to the extracellular environment.[27] Importantly, NNMT inhibition potentiated the absolute intracellular concentrations of NAD + and SAM, without altering the levels of NA and SAH in the adipocytes

On average, the price for a single injection ranges from $20 to $100

Also, the number of participants was very small