Vitamin B12 / Cobalamin

ID: vitamin_b12

Aliases: B12, cyanocobalamin, methylcobalamin, hydroxocobalamin

Type: compound

Route/form: oral/sublingual/nasal or IM/subQ injection depending form and deficiency context

Status: approved_or_supplement

Evidence level: approved / labelled

Best data tier: approved label + human controlled/review

Support scope: human, review/regulatory

Source types: government_review, human_rct, label

Linked sources: 3

Broad outcomes: Brain / mood / sleep

Reading note: These are curation notes anchored to linked sources, not a clinical recommendation or protocol.

Targets / mechanism

• cobalamin repletion
• DNA synthesis and methylation
• neurologic function in deficiency

Optimization domains

• nutrient
• neurology
• hematology
• energy
• deficiency

Research basis

• B12 is strongly evidence-backed when deficiency, malabsorption, pernicious anemia, vegan diet, or medication-related depletion is present.
• Injectable label context and high-dose methylcobalamin disease trials make route/form distinctions concrete.
• Optimization relevance is correcting a limiting deficiency, not creating stimulant-like energy in replete people.

Limits, risks, and missing evidence

• Normal-B12 individuals should not expect large energy, cognition, or performance effects from repletion.
• High-dose and injectable claims often overextend beyond deficiency biology.
• Interpreting B12 status can require MMA, homocysteine, CBC, diet, gut, and medication context.

Risk flags

• vitamin
• deficiency context
• route form matters
• overclaim risk

Linked papers, labels, and reviews

1. NIH Office of Dietary Supplements: Vitamin B12 fact sheet for health professionals
   government_review / ods_vitamin_b12_factsheet
   Nutrient status, deficiency, dosing forms, safety, and clinical context.
2. DailyMed label: Cyanocobalamin injection
   label / dailymed_cyanocobalamin_label
   Approved injectable vitamin B12 label context.
3. Efficacy and safety of ultrahigh-dose methylcobalamin in early-stage amyotrophic lateral sclerosis: a randomized clinical trial
   human_rct / pubmed_methylcobalamin_als_rct_2022
   Human high-dose methylcobalamin disease-context evidence; not a general wellness injection proof.