Mounjaro pens come with needles specifically designed for use with the pen
This is particularly critical if you take other medications

Practical Takeaways Recognize that intrinsic factor is essential for B12 absorption and cannot be replaced by dietary changes alone Understand that conditions affecting parietal cells can lead to B12 deficiency regardless of dietary intake Consider B12 monitoring in patients with gastric surgery, autoimmune conditions, or chronic PPI use Be aware that oral B12 supplements may be ineffective in intrinsic factor deficiency Appreciate that B12 deficiency can develop slowly and cause subtle neurological symptoms before anemia appears Consider alternative B12 delivery methods (sublingual, injectable) when intrinsic factor deficiency is suspected Related Studies and Research Vitamin B12 Intake From Animal Foods, Biomarkers, and Health Aspects Physiology, Stomach Pharmacology of Proton Pump Inhibitors Use of Proton Pump Inhibitors and Risk of Iron Deficiency: Population-Based Study Episode 25: The Great GERD Mistake - How Medicine Made Heartburn Worse and How to Fix It FAQs What happens if I dont have enough intrinsic factor

If you are working with [compounded retatrutide](/products/retatrutide-001), you are handling a lyophilized (freeze-dried) peptide that needs to be mixed with bacteriostatic water before [injection guide](/guides/how-to-inject-glp1-medications-guide)
At CoLaz we do not run diagnostic blood tests, so if you have not had your B12 confirmed, that is the first step