b12 and hcg injections for weight loss shots loss: Do they work, risks, benefits, more Vitamin B12 for Weight Loss:

As with many things, the individual will sort out the most effective method for them

Evidence for non-injectable routes is limited at best

Methylcobalamin is the most easily absorbed for people who have compromised digestive systems

9 In light of these findings, long-term use of these medications should be periodically reassessed, particularly in patients with other risk factors for vitamin B 12 deficiency

If B-complex vitamins are recommended, patients should be aware that high doses of vitamin B6 (exceeding 100 mg daily) can cause peripheral neuropathy

33 This article updates previous articles on this topic by Langan and Zawistoski, 4 and by Oh and Brown