When combined with vitamin B12, these ingredients form a synergistic blend that enhances energy production and supports a more efficient metabolic system
NAD injection protocols, especially when combined with B12 shots , can restore depleted levels faster and more effectively than oral supplements
PMID 11146368
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

Decreased stomach acid Atrophic gastritis Autoimmune pernicious anaemia Helicobacter pylori Gastrectomy, partial or complete Gastric bypass surgery (weight loss) Intestinal resection Partial or complete ileectomy Gastrointestinal neoplasms Malnutrition Eating disorders anorexia bulimia Inadequate diet Vegetarianism / veganism Malabsorption syndromes Alcoholism Crohns disease Coeliac disease (gluten enteropathy) Dipphyllobothrium infection blind loop syndrome diverticulosis inflammatory bowel disease small bowel overgrowth tropical sprue gastric irradiation ileal irradiation (bladder,cervix, uterus,prostate) Inborn errors of B12 metabolism Transcobalamin II deficiency Pancreatic exocrine insufficiency & Chronic pancreatitis Imerslund Gresbeck syndrome Zollinger Ellison Syndrome Bacterial overgrowth (small bowel) Fish tapeworm Advanced liver disease Drug induced causes Please note
However, while B12 shots are safe for many, they may not be suitable for everyone