What is it?
A large sugar polymer built from chains of glucose. It is made when certain bacteria, mainly Leuconostoc mesenteroides, grow on sucrose (table sugar), and it is then purified. In cosmetics it is used in small amounts as a binder and bulking agent. Dextran also has medical uses, including in some eye drops and, given by infusion, as a blood plasma volume expander.
Key information
- Dextran is a glucose polymer made by bacteria growing on sugar.
- The CIR Expert Panel concluded that dextran and related microbial gums are safe in the present practices of use and concentration.
- Reported cosmetic use was low: 51 products, at 0.2 percent or less.
- Rare severe allergic-type reactions have been reported when dextran is infused into a vein, a medical use unrelated to skin care.
More information
Dextran is made by fermentation. Strains of Leuconostoc mesenteroides grow on a sucrose solution and build long, branched chains of glucose. For medical grades, the chains are then partly broken down and separated into fractions of specific sizes. The Cosmetic Ingredient Review (CIR) Expert Panel reviewed dextran together with 33 other gums made by microorganisms, including xanthan gum and pullulan, and concluded in its 2012 final report that they are safe in the present practices of use and concentration. In the data it reviewed, dextran was reported in 51 cosmetic products at up to 0.2 percent.
The panel noted that these very large molecules are not expected to be significantly absorbed through the skin, and that the gums as a group were not irritating or sensitizing in testing. In one human study, labeled dextrans did pass through skin that had been deliberately abraded, with smaller molecules absorbed more than larger ones, a reminder that damaged skin is more permeable than intact skin. Rats fed a diet containing 2.5 percent dextran for 480 days showed no increase in tumors. The panel also discussed sodium dextran sulfate, a chemically modified form used to induce colitis in laboratory rodents, and judged those findings not relevant to cosmetic use.
Dextran’s known risk lies in medicine. In one hospital series in which dextran 70 was infused as a plasma volume expander during gynecological surgery or cesarean section, about 1 in 383 patients had an immediate anaphylactoid (severe allergic-type) reaction. In the United States, dextran 70 is also permitted at 0.1 percent in over-the-counter eye drops when combined with another soothing polymer. On cosmetic labels it appears simply as dextran.
Sources: Cosmetic Ingredient Review: Safety assessment of microbial polysaccharide gums as used in cosmetics (2012); Cosmetic Ingredient Review: Quick reference table of ingredient findings (September 2020); Code of Federal Regulations, 21 CFR 349.12 (via Cornell LII): Ophthalmic demulcents
