Cellulose Gum

Also known as Sodium Carboxymethyl Cellulose, Sodium Carboxymethylcellulose, Carboxymethylcellulose Sodium, NaCMC, CMC, Carmellose Sodium

Cellulose Gum (CAS 9004-32-4), the INCI name for Sodium Carboxymethyl Cellulose (NaCMC, CMC), is an anionic, water-soluble cellulose ether produced by alkali-catalyzed reaction of cellulose with sodium monochloroacetate. In cosmetics it functions as a viscosity-increasing agent, thickener, emulsion stabilizer, suspending agent, and film-former, typically used at concentrations up to 10%. The CIR Expert Panel originally assessed Cellulose Gum together with four related cellulose ethers (Hydroxyethylcellulose, Hydroxypropylcellulose, Methylcellulose, and Hydroxypropyl Methylcellulose) in 1986 (Elder, JACT 5(3):1-59, 1986) and issued an amended safety assessment in March 2009, concluding that these cellulose derivatives are safe in the present practices of use and concentration in cosmetics. The 1986 assessment found Cellulose Gum to be practically nontoxic by oral, dermal, inhalation, intraperitoneal, and subcutaneous routes; passes essentially unchanged through the GI tract; nonirritating to slightly irritating to skin and minimally irritating to eyes when tested at concentrations up to 100%; non-mutagenic; and not associated with significant teratogenic or reproductive effects. Its high molecular weight (typically tens to hundreds of kDa) precludes meaningful skin penetration, so systemic exposure from topical cosmetic use is negligible. The same chemistry is approved as food additive E466 (with extensive food-grade safety record) and is in pharmacopeial use as Carmellose Sodium. PubMed evidence specific to the cosmetic-thickener role is limited; the broader topical-application literature (e.g., NaCMC fibers in hydrocolloid wound dressings on irritant peristomal skin, PMID 34415254) is consistent with low cutaneous reactivity.