# A Survey of Preservatives Used in Cosmetic Products
## 4 Discussion  
[PERSON] et al. (2019) reviewed various ingredients in cosmetic products, including preservatives. Surprisingly, only 60% of the tested products contained at least one preservative, including 75% of the analyzed rinse-off products. In the present study, however, as many as 95.4% of the tested cosmetics, and every rinse-off product, contained at least one preservative. The most commonly identified preservatives by [PERSON] et al. (2019) were phenoxyethanol (48.7%), sodium benzoate (35.6%), and potassium sorbate (22%). These three preservatives also dominated in the present study, as their frequencies of use were higher, from 6.6 _p.p._ to 13.7 _p.p._, amounting to 60.9%, 42.2%, and 35.7%, respectively. Figure 10: Prevalence of preservatives in rinse-off products (n = 100) from ten different cosmetic brands. One clear difference was that no benzyl alcohol was used in Italian products, while it was present in 23.4% of the products in Poland. The more common preservatives, methylisothiazolinone (MI)/methylchloroisothiazolinone (MCI) and methylparaben, were used more in the [PERSON] et al. study (9.9% and 15.2%, respectively), than in ours (4.0% and 10.2%, respectively). Similar to our study, sodium benzoate dominated in rinse-off products (57.6%) and phenoxyethanol in leave-on cosme (70.1%). However, among the rinse-off products, DMDM hydantoin (14.1%) and triclosan (4.7%) were more popular than in the present study (3.0% and 0%, respectively). For leave-on products, parabens were more popular in the study by [PERSON] et al. than in the present study: methylparaben (20.8% vs. 13.5%), ethylparaben (14.3% vs. 5.5%), propylparaben (10.4% vs. 7.5%), and butylparaben (10.4% vs. 2.0%) [19]. Considerably different results than those in the present study were obtained in a review of preservatives in dermocosmetics (n = 1093), personal hygiene and cosmetic products sold in supermarkets (n = 249) on the Spanish market in 2015 [3]. In dermocosmetics, the most frequently used preservative was phenoxyethanol (43.1%), which was only present in 23.3% of supermarket cosme; in our study, it was the most common preservative, being present in 60.9%. The second-most common in Spain was citric acid, although it is not on the list of preservatives in Annex V to Regulation 1223/2009. The second- and third-most common preservatives in the present study were sodium benzoate (42.2%) and potassium sorbate (35.7%), respectively; in comparison, in Spain, sodium benzoate was present in 13.8% of dermocosmetics and 27.3% of supermarket products, while potassium sorbate was present in 8.7% and 13.3%, respectively. Benzyl alcohol was not recorded in the Spanish products but was noted in 23.4% of products in the present study. Methylparaben was identified in 14.5% of each Spanish preparation group, compared to 10.2% in the present study. Interestingly, methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI) were observed in 18.1% and 14.9%, respectively, of Spanish supermarket products [3]. Our present findings indicate that several of the most popular preservatives were present in cosmetic products on the Polish market: phenoxyethanol, sodium benzoate, potassium sorbate, benzyl alcohol, and methylparaben. As such, it is important to be aware of the safety aspects associated with their use. The most popular preservative in our research was phenoxyethanol. It exhibits a broad spectrum of antimicrobial activity, being effective against Gram-positive bacteria, e.g., _Staphylococcus aureus_, Gram-negative bacteria, e.g., _Pseudomonas aeruginosa_, and yeasts, such as _Candida albicans_ and molds. It demonstrates a lower inhibitory effect on the bacteria of the skin microbiome than other preservatives, such as methylparaben and methylisothiazolinone. According to the SCCS (2016), when used as a preservative in cosmetic products at a maximum concentration of 1%, phenoxyethanol is safe for all consumers, including children of all ages [20].