DMDM hydantoin is an antimicrobial

Antimicrobial

An anti-microbial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes or prevent the growth of microbes...

 formaldehyde releaser

Formaldehyde releaser

- Antimicrobials :Formaldehyde releasers are often used as an antimicrobial preservative in cosmetics. Examples include:* Quaternium-15* Imidazolidinyl urea * Diazolidinyl urea * DMDM hydantoin...

 preservative

Preservative

A preservative is a naturally occurring or synthetically produced substance that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical changes....

 with the trade name Glydant. DMDM hydantoin is an organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 belonging to a class of compounds known as hydantoin

Hydantoin

Hydantoin, which is also known as glycolylurea, is a heterocyclic organic compound that can be thought of as a cyclic "double-condensation reaction" product of glycolic acid and urea...

s. It is used in the cosmetics

Cosmetics

Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...

 industry and found in products like shampoos, hair conditioner

Hair conditioner

Hair conditioner is a hair care product that alters the texture and appearance of hair.-History:For centuries, natural oils have been used to condition human hair. These natural products are still used today, including essential oils such as tea tree oil and carrier oils such as jojoba oil...

s, hair gels and skin care products.

DMDM hydantoin works as a preservative because the released formaldehyde

Formaldehyde

Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...

 makes the environment less favorable to the microorganism

Microorganism

A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...

s.

Safety

Cosmetic Ingredient Review (CIR) Expert Panel has evaluated DMDM hydantoin and concluded "that it was safe to a great majority of consumers but has limited the concentration to 0.2% free formaldehyde due to the skin sensitivity of some individuals to this agent." A study found "An increase in the use of DMDM hydantoin in cosmetic products will also inevitably increase the risk of cosmetic dermatitis in consumers allergic to formaldehyde."