Essential Oils as Preservatives in Cosmetics: An Integrative Review

Cosmetics are more natural and sustainable due to pressure from the current society, which requires modification in traditional components, usually synthetic. Preservatives, which aim to extend products due to their ability to inhibit the growth and proliferation of microorganisms, are at the forefront of this change. The present study is characterized as an integrative review carried out about the use of essential oils (EO) as a cosmetic preservative, evaluating its effectiveness to replace or complement the current preservative system. The research’s guiding question was: EOs are effective as cosmetic preservatives and substitute equivalents for synthetic ones? Twenty-eight articles were selected in the consulted databases (Google Scholar, PubMed, and Scielo). EOs are promising natural preservatives either alone or combined with other EOs and with synthetic preservatives and additives. The results in vitro and cosmetic formulations demonstrated antimicrobial action in a broad spectrum of microorganisms. However, there is no standardization of the methods used to assess the antimicrobial efficacy and few studies with continuity, being necessary to carry out more studies concerning the preservative activity in ready-made cosmetic formulations and in vivo studies with humans using the final product for comparison and, in the future, replacement of synthetic preservatives by the OE.