# item.guide
Side-by-Side Comparison Essential Vitamins & Minerals

Vitamin B12 (Cobalamin) vs. Vitamin B7 (Biotin / Vitamin H)

Comparing 2 standards across 10 specifications. 10 key differences identified.

Comparing:
Vitamin B12 (Cobalamin)
Vitamin B7 (Biotin / Vitamin H)

Vitamin B12 is a cobalt-containing water-soluble corrinoid synthesized exclusively by microorganisms. Adult RDA is 2.4µg/day (no Upper Limit established), required for DNA synthesis, methionine synthase homocysteine conversion, and myelin sheath maintenance.

View full Vitamin B12 (Cobalamin) spec sheet →

Vitamin B7 is an essential sulfur-containing water-soluble vitamin serving as a prosthetic group for five carboxylase enzymes in gluconeogenesis, lipogenesis, and branched-chain amino acid catabolism. Adequate Intake (AI) is 30 µg/day (no Upper Limit established).

View full Vitamin B7 (Biotin / Vitamin H) spec sheet →

Specification Comparison Table

10 Parameters
Parameter / Spec
Nutrient Type
Water-Soluble Corrinoid Vitamin Water-Soluble Ureido-Tetrahydrothiophene Vitamin
Tolerable Upper Limit (UL)
None Established (Extremely low toxicity) None Established (No adverse effects recorded)
Chemical Forms
Methylcobalamin (Active), Adenosylcobalamin (Active), Cyanocobalamin (Stable synthetic) D-Biotin (Biologically active isomer), Biocytin (Biotinyl-lysine)
Primary Biological Function
Methionine synthase cofactor, Methylmalonyl-CoA mutase cofactor, Myelin integrity, Erythropoiesis Prosthetic group for Pyruvate Carboxylase (Gluconeogenesis), Acetyl-CoA Carboxylase (Fatty acid synthesis), Propionyl-CoA Carboxylase, Histone biotinylation
Deficiency Condition
Pernicious / Megaloblastic Anemia, Irreversible Neurological Peripheral Neuropathy Alopecia (Hair loss), Erythematous scaly periorofacial rash, Brittle nails, Neurological depression / hallucinations
Top Whole Food Sources
Oysters, Beef Liver, Sardines, Salmon, Beef, Dairy, Eggs (Absent in unfortified plant foods) Egg Yolk, Beef Liver, Salmon, Pork Chop, Sunflower Seeds, Almonds, Sweet Potatoes
Adult RDA / RDI
2.4 µg / day (2.6µg pregnancy, 2.8µg lactation)
Absorption Mechanism
Requires Gastric Acid, R-Protein, and Intrinsic Factor (IF) via Ileal Cubam receptors
Adult Adequate Intake (AI)
30 µg / day (35 µg during lactation)
Raw Egg White (Avidin) Interaction
Raw egg albumen contains avidin glycoprotein which binds biotin with Kd ~10^-15 M (the strongest non-covalent bond known), completely blocking absorption unless cooked