Quaternium-15, a preservative, is one of the most used substances and is added to several cosmetics and other industrial products. Quaternium-15 is a mixture of isomers, where the cis-form is the dominant form and where the trans-form is the minor component present as an impurity. Quaternium-15 can be found under a variety of names, most commonly those of the Dow Chemical Company: Dowicil 200 (cis isomer only), Dowicil 75 and Dowicil 100 (both a mix of cis and trans isomers). The isolated cis-compound is used primarily in cosmetic applications, with a maximum permitted concentration in the EU of 0.2%. DOWICIL 200 preservative (cis form) is used primarily as a preservative in a wide variety of personal-care and cosmetic products. It is designed to provide highly effective broad-spectrum antimicrobial activity, especially in water-based formulations. It is used in both leave-on and rinse-off application such as baby-care products, hair-care products, lotions, powders, and creams. The mixed product (cis- and trans-) is used in a wider range of formulations such as: emulsifiable metal-cutting fluids; latex and emulsion paints; liquid floor polishes and floor waxes; glues and adhesives. Recently, the cis-form has been classified as a CMR substance with the classification toxic to reproduction, category 3. This classification only concerns the cis-isomer:

Benzalkonium chloride, also known as BZK, BKC, BAC, alkyldimethylbenzylammonium chloride and ADBAC, is a type of cationic surfactant. It is an organic salt called a quaternary ammonium compound. In 2011, a large clinical trial designed to evaluate the efficacy of hand sanitizers based on different active ingredients in preventing virus transmission amongst schoolchildren was re-designed to exclude sanitizers based on benzalkonium chloride due to safety concerns. Benzalkonium chloride has been in common use as a pharmaceutical preservative and antimicrobial since the 1940s. While early studies confirmed the corrosive and irritant properties of benzalkonium chloride, investigations into the adverse effects of, and disease states linked to, benzalkonium chloride have only surfaced during the past 30 years. Benzalkonium chloride is classed as a Category III antiseptic active ingredient by the United States Food and Drug Administration. Ingredients are categorised as Category III when "available data are insufficient to classify as safe and effective, and further testing is required”. Benzalkonium chloride is excluded from the current United States Food and Drug Administration review of the safety and effectiveness of consumer antiseptics and topical antimicrobial over-the-counter drug products, meaning it will remain a Category III ingredient. The mechanism of bactericidal/microbicidal action is thought to be due to disruption of intermolecular interactions. This can cause dissociation of cellular membrane lipid bilayers, which compromises cellular permeability controls and induces leakage of cellular contents. Other biomolecular complexes within the bacterial cell can also undergo dissociation. Enzymes, which finely control a wide range of respiratory and metabolic cellular activities, are particularly susceptible to deactivation. Critical intermolecular interactions and tertiary structures in such highly specific biochemical systems can be readily disrupted by cationic surfactants. Benzalkonium chloride is a human skin and severe eye irritant. It is a suspected respiratory toxicant, immunotoxicant, gastrointestinal toxicant and neurotoxicant.

Nerolidol (aka peruviol) is a naturally occurring sesquiterpene found in the essential oils of many types of plants and flowers. The aroma of nerolidol is woody and reminiscent of fresh bark. It is used as a flavoring agent and in perfumery. It is also used in non-cosmetic products such as detergents and cleansers. Additionally, it is known for several biological activities including antioxidant, anti-fungal, anticancer, and antimicrobial activities.

Farnesol, (2E,6E)- is an isoprenoid found in many aromatic plants and is also produced in humans, where it acts on numerous nuclear receptors and has received considerable attention due to its apparent anticancer properties. Farnesol is present in many essential oils such as citronella, neroli, cyclamen, lemon grass, tuberose, rose, musk, balsam, and tolu. It is used in perfumery to emphasize the odors of sweet floral perfumes. Its method of action for enhancing perfume scent is as a co-solvent that regulates the volatility of the odorants. It is especially used in lilac perfumes. Farnesol is a natural pesticide for mites and is a pheromone for several other insects. In a 1994 report released by five top cigarette companies, farnesol was listed as one of 599 additives to cigarettes. Farnesol has been suggested to function as a chemopreventative and anti-tumor agent. Farnesol is subject to restrictions on its use in perfumery as some people may become sensitized to it, however, the evidence that farnesol can cause an allergic reaction in humans is disputed.

Triphosphoric acid (also tripolyphosphoric acid), a condensed form of phosphoric acid. Sodium tripolyphosphate (STPP) is used as a preservative for poultry, meat, and seafood; it’s added to processed cheeses as an emulsifier and is used in food industry as an E number E451.

D&C Black #2 is the name, given by the FDA, for a highly pure form of carbon black prepared by combusting aromatic petroleum oil in the "oil furnace" process. It consists, essentially, of pure carbon. The Cosmetic, Toiletries and Fragrance Association (CTFA) petitioned the U.S. Food and Drug Administration (FDA) for approval to use carbon black in cosmetic formulations. The FDA granted approval on August 29, 2004, and now D&C Black #2 is used in all cosmetic products: mascaras, eyeliners, brush-on-brow, eyeshadows, and lipsticks.