In a comparison of skin care products based on price, researchers have found that less expensive products tend to contain fewer allergens.
A test of 100 products showed that 26 allergenic substances were found in both expensive and inexpensive products. The products that fell under the expensive category averaged more allergens per product than the inexpensive products, according to a study published online ahead of print in the journal Dermatitis (Oct. 20, 2018).
Researchers used 50 expensive and 50 inexpensive moisturizers available online at CVS Health—chosen as the source because it is the largest drugstore chain in the United States—to test for allergens found in the Core Allergen Series, which includes 80 allergens, and the North American Contact Dermatitis Group’s allergen series, which includes 70 allergens. Some additional allergens not listed in either series were also considered based on previously published studies and expert opinions.
Sorting products from highest price to lowest price, researchers choose the 50 most expensive, and 50 least expensive items of the 607 products available online from CVS under the categories “Creams and Serums,” “Moisturizer,” “Cream,” “Face Cream,” and “Night Cream.” Eye creams, neck creams, serums, and emulsions, as well as products containing SPF, tinted products, and medicated products were excluded from the study.
Copyright-free photo by Karolina Mis via goo.gl/7Mxy4p (CC BY 2.0)
The inexpensive moisturizers ranged in price between $0.99 and $8.50, while the expensive moisturizers ranged from $39.99 to $579.99 (all price in US dollars). In total, 414 allergens were found in the expensive group, and 280 were found in the inexpensive group.
Allergens were grouped into seven categories: acrylates, botanicals, emulsifiers, fragrances, preservatives, tocopherols, and “other.”
Fragrances were the most common potential allergens found in the expensive moisturizers—found in 88%—and of all of the allergen types, were found at significantly higher rates in the expensive products than the inexpensive products. The next most common allergens were preservatives, tocopherols, botanicals, emulsifiers, acrylates, and “other.”
The conclusion reached by the study is that “physicians may counsel cosmetic-induced allergic contact dermatitis patients that monetary value is not a suitable proxy for evaluating the risk of ACD.”
Arranged from most to least, here are the top allergens found in the pool of products:
Fragrances were the most common potential allergens found in the expensive moisturizers—found in 88% of those tested—and the second most common in the inexpensive products, found in 62%. Of all of the potential allergens, fragrances were the allergen found in the statistically highest rate in expensive products. For the purposes of this study, fragrance chemicals include amylcinnamaldehyde, hydroxycitronellal, geraniol, eugenol, citral, farnesol, citronellol, hexyl cinnamic aldehyde, coumarin, limonene, linalool, lilial, benzyl sa- licylate, and sesquiterpene lactones/α-bisabolol, as well as some unspecified fragrance formulas protected as intellectual property.
Preservatives were the second most common allergen found in the expensive moisturizers—and first overall when combining both expensive and inexpensive categories. Preservative chemicals include benzalkonium chloride (BAK), benzyl alcohol and benzoic acid, diazolidinyl urea, disodium sulfite/sodium metabisulfite, dimethyloldimethyl (DMDM) hydantoin, ethylhexylglycerin, imidazolidinyl urea, iodopropynyl butylcarbamate, methylisothiazolinone (MI), parabens, phenoxyethanol, sodium benzoate, and sorbic acid.
Tocopherols were the third most common allergen found in both the expensive and inexpensive products. The organic compound, which also has antioxidant effects, was found in 58% of expensive products and 60% of inexpensive products contained the organic compound.
Botanical extracts were the fourth most common allergen found in both expensive and inexpensive products. In expensive products, they were found 40% of the time, and in inexpensive products it was found 56% of the time. Botanicals include Aloe vera, Anthemis nobilis, Apis mellifera, Arnica montana, Chamomilla, officinalis, Echinacea angustifolia, Echinacea purpurea, Lavandula angustifolia, Matricaria chamomilla, and ylang-ylang oil. Researches noted that “botanicals may also be used to perfume moisturizing products; however, the substances listed in this section were not doubly included as fragrances.”
Emulsifiers were the fifth most common allergen found in both expensive and inexpensive products. They were found 38% of the time in expensive products and 36% of the time in inexpensive products. Emulsifiers include lanolin, pro- pylene glycol (PG), and sorbitan sesquioleate (SSO), in addition to SSO-related substances such as lanolin, pro- pylene glycol (PG), and sorbitan sesquioleate (SSO), which can cause cross-reactions.
Acrylates were the sixth most common allergen found in both expensive and inexpensive products. Found in 14% of the expensive products and 6% of the inexpensive products, acrylates include 2-hydroxyethyl methacrylate, ethyl acrylate, and methyl methacrylate.
For the purposes of this study, “Other” refers to “miscellaneous ingredient found in this study at minuscule quantities and frequencies.” Such ingredients include butylated hydroxytoluene (BHT), chlorhexidine digluconate, and hydroquinone.