Cosmetic preservatives: the ingredients, their EU limits and the claims

Why products with water need preserving

EU law defines preservatives as substances exclusively or mainly intended to inhibit the development of microorganisms in the cosmetic product (Article 2).¹ They protect the product, not your skin. A review of preservation strategies gives the reason: cosmetics, like any product containing water and organic or inorganic compounds, need protection from microbial contamination, both for the user's safety and for shelf life.²

The EU's Scientific Committee on Consumer Safety (SCCS) names two sources of contamination: production and filling, and use at home, where every opening and every touch of hands and skin adds microbes. It describes a challenge test, in which the finished formula is deliberately contaminated and the fall in microbes measured, as mandatory for any product that could deteriorate or risk infecting the user. Routine testing of each batch can be skipped in some justified cases, such as products with more than 20% alcohol.³

Annex V: the EU's list of permitted preservatives

A cosmetic sold in the EU may not contain preservatives other than those listed in Annex V of the cosmetics regulation, and listed ones must be used within the conditions set there (Article 14).⁴ Each entry gives a maximum concentration in the ready-for-use product; some add product types, warnings or limits for young children. Some of the entries:

Phenoxyethanol and Sodium Benzoate have their own articles; Potassium Sorbate, Benzyl Alcohol, Methylparaben, Dehydroacetic Acid and Chlorphenesin have dictionary entries. Benzyl alcohol is also a fragrance allergen that EU labels must name above set thresholds (Annex III, entry 45)¹, which EU fragrance allergen labels explains.

Antimicrobial, but not a listed preservative

Not every ingredient that helps keep a product free of microbes is a listed preservative. Ethylhexylglycerin has no Annex V entry, and CosIng lists it as a deodorant and skin conditioning ingredient.⁵¹ It is commonly used alongside phenoxyethanol, and a laboratory study found that it strengthens phenoxyethanol's effect on bacteria by damaging their cell membranes.⁶ A patch-test study describes it as used for its surfactant, emollient, skin conditioning and antimicrobial properties.⁷

Formulators can also make a product harder for microbes to live in. A review of "self-preserving" cosmetics describes combining several hurdles, such as good manufacturing practice, suitable packaging, low water activity and a low or high pH, with ingredients that have antimicrobial properties but are not regulated as preservatives.⁸ Packaging, pH and manufacturing hygiene do not appear on an ingredient list at all.

Formaldehyde releasers and the "releases formaldehyde" warning

Formaldehyde itself is banned in EU cosmetics: it is classified as a carcinogen (category 1B) and a skin sensitiser, and sits in Annex II, the list of prohibited substances, at entry 1577. Some preservatives still on Annex V work by gradually releasing formaldehyde, and are known as formaldehyde releasers.⁹ The FDA's list of common cosmetic allergens names seven of them¹⁰, and EU law treats each as follows:

Under the Annex V preamble, point 2, any finished product containing an Annex V substance that releases formaldehyde must carry the warning releases formaldehyde when the total formaldehyde released exceeds 0.001% (10 ppm), however many releasers it contains. Products that met the old rules could be placed on the market until 31 July 2024 and made available until 31 July 2026.¹ The old threshold was 0.05%; the SCCS advised that it did not sufficiently protect people sensitised to formaldehyde, and that 10 ppm would protect the vast majority of them.¹¹⁹ DMDM Hydantoin and Diazolidinyl Urea have dictionary entries; sensitive skin and cosmetic labels covers the allergy side.

What "preservative-free" means

"Preservative-free" is a claim, not a legal category. EU guidance on "free from" claims says it should not be used when a product contains ingredients that protect it against microorganisms but are not in Annex V, alcohol being its example, though the claim may be appropriate if the company has evidence, such as a challenge test of the formula without them, that they do not contribute to protecting it. The same guidance says "free from formaldehyde" is not allowed on a product that contains a formaldehyde releaser.¹² It is guidance, not law; what "clean" means on a label covers "free from" claims in general.

In a Belgian study of 13 people allergic to ethylhexylglycerin, many of the products responsible were leave-on cosmetics advertised as "hypo-allergenic" or "preservative-free".⁷ Read the claim as a statement about listed preservatives, and the ingredient list for what is there instead.

What to look for on the label

• Find the preservatives by their names in the tables above. A product can use more than one, and in the EU only Annex V substances may be used as preservatives.⁴
• "Releases formaldehyde" on an EU pack means a formaldehyde releaser is present and the total released exceeds 10 ppm.¹
• Use the tools. Paste a list into the ingredient checker to see which names are listed as preservatives, or compare two products with the ingredient list comparison tool.

A preservative on a list is not a verdict on the product. EU limits apply to every product sold there, and the list cannot show how much of any preservative is present.