The tetraacetylated N-Azidoacetyl-glucosamine (Ac 4GlcNAz) provides a non-radioactive alternative for glycoconjugate vi-sualization. It is cell-permeable, intracellularly processed and incorporated instead of its natural monosaccharide counterpart N-Acetylglucosamine(GlcNAc). The resulting Azide-functionalized glycoconjugates can subse-quently be detected via Cu(I)-catalyzed or Cu(I)-free Click Chemistry that offers the choice to introduce a Biotin group (via Azides of Biotin or DBCO-containing Biotin, respectively) for subsequent purification tasks or to introduce fluorescent group (via Azides of fluorescent dyes or DBCO-containing fluorescent dyes, respectively) for subsequent microscopic imaging. Recommended concentration for metabolic labeling: 25-75 M. This concentration range may serve as a starting point for an individual assay set-up.