CAS 21764-56-7 appears in our catalog under these names: L–Alanine–1–13C, L-ALANINE-1-13C, 99 ATOM % 13C, L-alanine-1-13c, 99%, 99%, L-Alanine-1-13C, 99.0%. Offered by: GLPBio, Sigma-Aldrich, Chemat, MedChemExpress. Available pack sizes: 25mg, 50mg, 500MG, 50 mg, 25 mg.