Methylcobalamin - The Superior Form of B12 Supports Brain Cells and Nerve Tissue Dietary Supplement Suitable for Vegetarians/Vegans Methylcobalamin (Methyl B-12) is better absorbed and retained than other forms of B12 (e.g., cyanocobalamin). Methyl B-12 supports nerve tissue and brain cells, promotes better sleep and recycles (via methylation) homocysteine, an oxidizing metabolite, back into the amino acid methionine. Also, vegetarians/vegans often require B12 supplementation.