Vitamin B Deficiency: While only 1-1.5 percent of Americans have a true deficiency, as many as 40 percent fall within the low-normal range for Vitamin B levels
Direct Dosage: A single B12 injection often delivers a much higher dose directly into the system than a typical daily oral tablet, particularly when considering the limited absorption rate of the latter, contributing to their perceived and actual strength. However, for individuals with mild dietary deficiencies and no underlying absorption problems, high-dose oral B12 supplements (e.g., 1000-2000mcg daily) can sometimes overcome the need for intrinsic factor by allowing for a small amount of passive absorption, eventually raising levels, though this method is less predictable and slower than direct injection
b , 8, 20, 29 However, experimental injection of sclerosing agents into normal dorsal veins of rabbit ears yields effective vessel sclerosis in a concentration-dependent manner
No human pharmacokinetic data exists to confirm whether these doses translate to effective systemic exposure