Methylcellulose (or methylcellulose) is a chemical compound derived from cellulose. It is a hydrophilic white powder in pure form and dissolves in cold (but not in hot) water, forming a clear viscous solution or gel. It is sold under a variety of trade names and is used as a thickener and emulsifier in various food and cosmetic products, and also as a treatment of constipation. Like cellulose, it is not digestible, not toxic, and not an allergen.
Thickener and emulsifier
Methylcellulose is very occasionally added to hair shampoos, toothpaste and liquid soaps, to generate their characteristic thick consistency. This is also done for foods, for example, ice cream or croquette. Methyl cellulose is also an important emulsifier, preventing the separation of two mixed liquids because it is an emulsion stabilizer.
The E number of methyl cellulose as food additive is E461. E464 is Hydroxypropylcellulose and better soluble in water.
Methylcellulose (a.k.a. "Methocel", produced by Dow Chemical or "Mecellose", produced by Samsung Fine Chemicals) is also used as paint rheological modifier to prevent paint sagging.