oral vs injection b12 Vitamin Injections vs. Supplements: Which Works Best? Sublingual B12 vs. B12 Injections:

The best way is through a nutrient-dense diet

It's the bioactive form (no conversion required), retains longer in tissues, and a meta-analysis of randomized controlled trials found mecobalamin (methylcobalamin) effective for peripheral neuropathy

Tran may recommend laboratory testing to measure your vitamin B12 levels, along with related markers like methylmalonic acid and homocysteine

[95] Intramuscular or intravenous injection [edit] Injection of hydroxycobalamin is often used if digestive absorption is impaired, [2] but this course of action may not be necessary with high-dose oral supplements (such as 0.51.0 mg or more), [97] [98] because with large quantities of the vitamin taken orally, even the 1% to 5% of free crystalline B 12 that is absorbed along the entire intestine by passive diffusion may be sufficient to provide a necessary amount

When the terminal ileum is surgically removed, as is often the case in individuals with inflammatory bowel disease, colorectal cancer, familial adenomatous polyposis, or other conditions requiring ileostomy or pouch formation, but also urostomy, B12 absorption may become severely compromised

Increase of Fat Oxidation and Weight Loss in Obese Mice Caused by Chronic Treatment with Human Growth Hormone or a Modified C-terminal Fragment