Levulinic Acid

What it is

Levulinic acid is a small organic acid made from sugars, and in cosmetics it almost never travels alone: it is paired with sodium levulinate, its own sodium salt. The Panel that assessed the two describes them as essentially identical in aqueous solution, so in a water-based mask the distinction between acid and salt is a good deal less than the two names suggest. Its declared cosmetic functions are skin conditioning and, separately, fragrance.

What it does well

• Antimicrobial in practice, without being a listed preservative

  The effect is real and documented: the same assessment records levulinic acid stunting bacterial growth in preserved ready-to-eat meats, and working as a cytocidal agent in oral rinse solutions. What keeps it off the EU's preservative list is not a want of effect but its declared purpose. Legally it is a skin-conditioning agent; functionally it is doing a preservative's job.

  Moderate evidence

• Assessed as safe, with a condition attached

  The Expert Panel concluded levulinic acid and sodium levulinate are safe in cosmetics in the present practices of use and concentration when formulated to be non-irritating. That last clause is doing real work: the finding is about the finished formula, not about the ingredient in isolation.

  Moderate evidence

Worth knowing

• The condition the Panel attached is about eyes, not skin

  "Formulated to be non-irritating" sounds like boilerplate, and it is not. The Panel attached it because these ingredients turn up in products that can incidentally reach the eyes, and neat levulinic acid tested as an eye irritant in two separate assays. That is the raw material rather than a finished mask, and on skin the same report found no sensitisation in human testing - so the practical reading is the ordinary one: keep a mask off the eyelid and out of the eye, and rinse if it gets there.

  Matters most toAnyone laying a sheet mask close to the eye area, or using a wash-off mask around the eyes.

• It is also recorded as a fragrance ingredient

  Levulinic acid has a declared function as a fragrance ingredient as well as a conditioning one, so a mask presented as fragrance-free can still contain it. That does not make the claim false - it is not one of the fragrance allergens the EU requires to be named separately on a label - but it is worth knowing if you avoid aroma chemicals entirely.

  Matters most toAnyone who avoids fragrance materials beyond the declarable allergen list.

Where the EU stands

Sources (2)

Every link goes to the original: a journal, a PubMed record or an EU document.

1. [1]
   Safety Assessment of Levulinic Acid and Sodium Levulinate as Used in Cosmetics

   Cosmetic Ingredient Review, International Journal of Toxicology 44:91S-99S · 2025 · doi:10.1177/10915818251359228

   The Expert Panel concluded that Levulinic Acid and Sodium Levulinate are safe in cosmetics in the present practices of use and concentration described in the safety assessment when formulated to be non-irritating. Both are reported to function as skin conditioning agents, and Levulinic Acid is also reported to function as a fragrance ingredient. Checked 16 August 2026.

2. [2]
   Safety Assessment of Levulinic Acid and Sodium Levulinate as Used in Cosmetics (Final Report)

   Cosmetic Ingredient Review, Expert Panel for Cosmetic Ingredient Safety · 2021

   The final report behind the published assessment, and the document that says why the conclusion is conditional. Because these ingredients are used in products that might incidentally reach the eyes, "the Panel was concerned that the potential exists for ocular irritation with the use of products formulated using these ingredients. The Panel, therefore, specified that products containing Levulinic Acid or Sodium Levulinate must be formulated to be non-irritating." The eye data are on the neat raw material: in an EpiOcular human cornea assay mean tissue viability was 2.5%, against an irritation threshold of 60%, and a BCOP assay returned an in vitro irritancy score of 84.29, in the range for serious eye damage. The skin picture is different - 26 volunteers exposed to 4% levulinic acid in a human maximisation test showed no sensitisation, and two human tests of products containing sodium levulinate at 0.4011% and 0.57% found no irritation or sensitisation. The Panel also noted negative log Kow values for both, suggesting a low likelihood of either crossing the stratum corneum, while cautioning that they may enhance the penetration of other ingredients. Checked 18 August 2026.