What are fragrance solvents and fixatives
Fragrance solvents are substances used to dissolve the various ingredients in a fragrance or perfume.
Fragrance fixatives function to equalize the varying volatilities of a perfume so more volatile ingredients do not evaporate before less volatile ones. They are important to maintaining a consistent scent over time as it allows for slower evaporation of the more volatile ingredients.
Fixatives themselves can either lend a particular scent note to the perfume or are odorless.
Some chemical substances can serve to varying degrees as both solvents and fixatives.
Human health and environmental concerns associated with some solvents and fixatives
Diethyl phthalate (DEP, CASRN 84-66-2) is a phthalate ester used as a fragrance solvent and fixative and valued for its low cost, odorlessness, and versatility as a solvent. Although some sources report that DEP has limited fixative properties, that has been an important use of the product.
Northwest Green Chemistry evaluated alternatives to five ortho phthalates deemed to be of concern to Puget Sound that included DEP. The report cited studies showing that about 25% of all cosmetics (for adults and children) and up to 90% of perfumes were found to contain DEP (Northwest Green Chemistry, 2018).
Demand for the removal of DEP from fragrances is being driven by consumer concerns, especially for children and women’s health (Eden Botanicals, 2015). While the US Food & Drug Administration (FDA) states that DEP “does not pose known risks for human health as it is currently used in cosmetics and fragrances,” it does pose risks as a skin sensitizer and as an irritant, as well as an acute aquatic toxin (Northwest Green Chemistry, 2018).
Alternatives to DEP Fragrance Solvents
Solvent and fixative alternatives must be functional alternatives that could replace DEP as a fragrance solvent or fixative. Such performance requirements are based on current use patterns and fragrance formulator feedback. For example, preferred alternatives are those that function as a solvent and/or a fixative and that do not have a strong odor that would unfavorably alter the fragrance profile and inhibit formulation of the fragrance to achieve the desired results.
Alternatives must also meet minimum requirements to be included in this portfolio; alternatives must not be listed as a High Priority Substance on the Sephora Public Chemicals Policy, and they should not be found on the Cradle to Cradle Certified Restricted Substances List (RSL) v4 (DRAFT), the REACH Annex 14 (Candidate List for Authorisation) or the REACH Annex 17 (Restricted List).
Preferred alternatives are those that would be effective as solvents and/or fixatives for fragrances, for which comprehensive human health and environmental toxicity and fate data are available, and for which the human and environmental health hazards are low.
This ChemForward Fragrance Fixative and Solvent Portfolio includes full chemical hazard assessments for dipropylene glycol, triethyl citrate, triacetin and isopropyl myristate. Each ChemForward portfolio is dynamic and more alternatives may be added over time.
Cradle to Cradle Products Innovation Institute. 2019. Draft v4 Basic Level Restricted Substances List (RSL)
Eden Botanicals. 2015. Fixatives and Their Function in Natural Perfumery
European Chemicals Agency (ECHA). Authorisation list. Accessed March 2020
European Chemicals Agency (ECHA). Restricted substances by Annex XVII to REACH Regulation. Accessed March 2020
FDA. 2018. Fragrances in Cosmetics
Northwest Green Chemistry. 2018. Alternatives to Five Phthalates of Concern to Puget Sound