Vitamin B12, when injected, can increase energy, decrease inflammation, improve metabolism, and support sleep, mood, and memory
Many do well on oral supplements, but someone who is already symptomatic and confirmed low may recover faster with injections before switching to oral maintenance
10.18637/jss.v036.i03 61 YamaneK.UsuiT.YamamotoT.TsukamotoT.SomaY.YoshimuraN.et al (1995)
The following criteria were considered: Full economic evaluations: cost-utility analysis, cost-effectiveness analysis, cost-benefit analysis Economic evaluations reporting incremental cost-effectiveness ratios (i.e., cost per quality-adjusted life year/life years gained or cost per event avoided) Studies in patients with confirmed vitamin B12 deficiency Studies in English Abstracts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained
Common side effects are rare but may include: Mild gastrointestinal symptoms such as nausea or diarrhoea (though less common with sublingual than oral routes) Headache or dizziness in some users Skin reactions, including itching or rash, particularly in individuals sensitive to cobalt (a component of cobalamin) Unlike some other B vitamins, oral B12 supplements rarely affect urine colour
Measuring serum biomarkers such as B 12 or MMA is neither helpful nor indicated in assessing or monitoring clinical improvement
