6M Guanidine Hydrochloride is a ready-to-use solution of guanidine hydrochloride, a chaotropic denaturant, in purified water. The 1 L fill supports laboratory and pilot-scale use.

It is commonly used to denature and solubilize proteins, including inclusion bodies, for refolding, reduction, and mass spectrometry sample preparation. Remove or dilute guanidine before tryptic digestion and LC-MS, since it inhibits trypsin and suppresses ionization.