Method Absorption Rate Advantages Disadvantages Oral pills 1.2-40% depending on intrinsic factor Convenient, widely available Poor absorption, especially with age or GI issues Sublingual Slightly better than pills No need for intrinsic factor, easy to use Still less effective than injectable forms In-clinic IM injection Nearly 100% Highly effective, professionally administered Requires clinic visits, potential travel and waiting time At home B12 injection Nearly 100% Highly effective, convenient, no travel needed Requires training, prescription, and comfort with self-injection IV infusion 100% Immediate delivery to bloodstream Most expensive, requires professional administration For many people especially those with serious deficiencies, digestive disorders, or pernicious anemia at home B12 injection offers the sweet spot of effectiveness and convenience
A 1,000-microgram tablet would be expected to result in a 10 to 20-microgram dose
Although usually not indicated on product labels, it may be best to take a B vitamin with a large meal
There's no one-size-fits-all stack
Improves Low Sperm Count Helps with Fetal Development During Pregnancy Helps Prevent or Treat Diabetic Neuropathy Risks/Drawbacks of B12 Injections: Problems with Absorption: Even if someone receives high doses of vitamin B12, it doesnt necessarily mean that his or her body has the ability to properly absorb and use the whole dose