Quaternium-15

Quaternium-15 is a preservative found in many cosmetics and industrial substances that releases formaldehyde. It can be found in numerous sources, including but not limited to: mascara, eyeliner, moisturizer, lotion, shampoo, conditioner, nail polish, personal lubricants, soaps, body wash, baby lotion or shampoo, facial cleanser, tanning oil, self-tanning cream, sunscreen, powder, shaving products, ointments, personal wipes or cleansers, wipes, paper, inks, paints, polishes, waxes and industrial lubricants. It can cause contact dermatitis, a symptom of an allergic reaction, especially in those with sensitive skin, on an infant's skin, or on sensitive areas such as the genitals.

Its chemical formula is C9H16Cl2N4. It can be found under a variety of names, including: Dowicil 75; Dowicil 100; Dowco 184; Dowicide Q; 1-(3-Chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride; N-(3-chloroallyl) hexaminium chloride; hexamethylenetetramine chloroallyl chloride; 3,5,7-Triaza-1-azoniaadamantane; 1-(3-chloroallyl)-chloride.

Formaldehyde-releasing
Other formaldehyde-releasing preservatives similar to quaternium-15 include: imidazolidinyl urea (Germall®), diazolidinyl urea (Germall II®), DMDM hydantoin (Glydant®), bromonitropropane diol (Bronopol™), tris(hydroxymethyl) nitromethane (Tris Nitro®), and sodium hydroxymethylglycinate.

Safety concerns
Quaternium-15 is an allergen, and can cause contact dermatitis in susceptible individuals. Many of those with an allergy to quaternium-15 are also allergic to formaldehyde. Allergic sensitivity to quaternium-15 can be detected using a patch test.