[9] Certain medications interfere with B12 absorption, most notably metformin (used for type 2 diabetes), proton pump inhibitors (PPIs), and H2-receptor antagonists when used long-term, as they reduce stomach acid production necessary for B12 release from food proteins
Expectations Matter Individual response varies
Synthetic ERR// Agonist Induces an ERR-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity
Vitamin B12 has long been regarded as a critical element in supporting healthy body processes
Paediatric and Perinatal Epidemiology , 32 (1), 100111
That is a legitimate concern and it applies to fully compliant, in-spec, USP-grade water , not to any knock-off