Nerve function, energy metabolism, and red blood cell formation — commonly deficient on GLP-1 therapy, and almost never supplemented.
Vitamin B12 (cobalamin) is a water-soluble vitamin essential for neurological function, DNA synthesis, red blood cell formation, and energy metabolism. It is one of the few vitamins found almost exclusively in animal-sourced foods — making it uniquely vulnerable to deficiency when food intake drops or animal protein is reduced.
Anchor uses methylcobalamin, the bioactive form of B12. Most supplement products use cyanocobalamin, a synthetic form that requires hepatic conversion before the body can use it. Methylcobalamin is used directly, retained better in neural tissue, and is the preferred form for addressing the neurological symptoms associated with deficiency.
B12 deficiency risk on GLP-1 therapy comes from two directions. First, the medication significantly reduces appetite — and since B12 is found primarily in meat, fish, eggs, and dairy, less eating means less B12. Second, some GLP-1 medications affect gastric acid production; stomach acid is required to cleave B12 from food proteins before absorption can occur. Both factors compound over months of therapy.
Early B12 deficiency is often subtle: persistent fatigue, brain fog, mild numbness or tingling in extremities. These are symptoms that are easy to attribute to the therapy itself, a lower-calorie diet, or just adaptation — and easy to miss until the deficiency is significant. Consistent supplementation prevents that trajectory entirely.
500mcg of methylcobalamin is a supplemental dose that reliably maintains adequate serum B12 in healthy adults, including those with reduced dietary intake. B12 absorption from food is limited to approximately 1–2mcg per meal; supplemental B12 uses a different (passive diffusion) absorption pathway that allows a small percentage of much larger doses to be absorbed even when the intrinsic factor pathway is compromised. At 500mcg, passive absorption alone covers the daily requirement multiple times over.
Vitamin B12 is one of two micronutrients in Complete — Anchor's formula for the vitamin and mineral gaps that smaller meals create. It works alongside Vitamin D3 to cover the two deficiencies most consistently observed in people on peptide therapy and calorie-restricted diets.
Complete addresses the two micronutrient deficiencies most common on GLP-1 protocols.
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