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Guanidine hydrochloride

≥99% (titration), organic base and chaeotropic agent

Aminoformamidine hydrochloride, Aminomethanamidine hydrochloride, Guanidinium chloride
Linear Formula:
NH2C(=NH)NH2 · HCl
CAS Number:
Molecular Weight:
EC Number:
MDL number:
PubChem Substance ID:

biological source

synthetic (organic)

Quality Level


≥99% (titration)


crystalline powder


RNA extraction: suitable


≤0.3% water (Karl Fischer)




(25 °C, 4.6 - 6 at 573 g/L)


180-185 °C (lit.)


H2O: 6 M


1.3 g/cm3 (lit.)


≤0.10 at 260 nm in H2O at 6 M

SMILES string




InChI key


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Guanidine hydrochloride (GdnHCl) has been used:
  • to perform absolute quantitation of amyloid-beta (Aß) isoforms in plasma
  • in protein carbonylation assay
  • for the quantification of glycosaminoglycans (GAG)
  • for denaturation of cow′s milk allergens
  • as a control in antiviral screening tests with coxsackievirus B3 (CVB3)
  • in RNA isolation to dissociate nucleoproteins and inhibit RNase
Strong chaotropic agent useful for the denaturation and subsequent refolding of proteins. This strong denaturant can solubilize insoluble or denatured proteins such as inclusion bodies. This can be used as the first step in refolding proteins or enzymes into their active form. Urea and dithiothreitol (DTT) may also be necessary.


25, 100, 500 g in poly bottle
2, 10, 25 kg in poly drum
1 kg in poly bottle
Each kit contains 3 x 100G samples, each sample from a uniquely manufactured lot.

Biochem/physiol Actions

Guanidine hydrochloride (GdnHCl) is hydroscopic and a small molecule. It is a potent denaturant of enzymes, which results in conformational changes in the enzyme, leading to complete loss of enzyme activity. GdnHCl is involved in blocking the activity of heat shock protein 104 (Hsp104) adenosine triphosphatase (ATPase) in vivo. It is involved in denaturing alkaline phosphatase (ALPase) in Haliotis diversicolor. GdnHCl leads to the deactivation of enzymes like papain and aminoacylase. GdnHCl, at higher concentrations, is effective in virus inactivation, such as herpes simplex virus 1 (HSV-1).


May agglomerate upon storage. The quality of the product does not appear to be affected and solutions prepared from the free-flowing and lumpy guanidine hydrochloride appear identical. For free-flowing material, please see our Redi-Dri free-flowing product number RDD001.

Preparation Note

In order to make an 8M solution in water, one must heat the solution to 35 °C for approximately 30 minutes.
The maximum solubility of guanidine hydrochloride in water at room temperature is approximately 6M.

Legal Information

Redi-Dri is a trademark of Sigma-Aldrich Co. LLC


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Hazard Statements

Hazard Classifications

Acute Tox. 4 Inhalation - Acute Tox. 4 Oral - Eye Irrit. 2 - Skin Irrit. 2

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificate of Analysis

Enter Lot Number to search for Certificate of Analysis (COA).

Certificate of Origin

Enter Lot Number to search for Certificate of Origin (COO).

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