No known benefits

Bronopol at a glance

  • Used as a preservative in numerous commercial applications
  • Has broad-spectrum antimicrobial activity
  • Can cause allergic contact dermatitis
  • White crystals in its raw form

Bronopol description

Bronopol, also known as bronosol, is an organic compound first synthesized in 1897. It is used as a preservative in numerous commercial applications thanks to its broad-spectrum antimicrobial activities. The ingredient name you’ll see on the label is 2-bromo-2-nitropropane-1,3-diol. While it does an exemplary job of preventing bacterial growth (which is always a good thing, as some cosmetics without preservatives would be prone to rapid microbial growth) in both rinse-off and leave-on products, it is also known to cause allergic contact dermatitis. There are several other, equally effective preservatives that do not present this potential for side effects. In its raw form, bronopol appears as white crystals. Use levels in cosmetics range from 0.02–0.05%, a testament to this preservative’s potency.

Bronopol references

  • PubChem, Website, Accessed April 2024
  • Contact Dermatitis Institute, Website, Accessed April 2024
  •, Website, Accessed April 2024
  • ULProspector, Website, Accessed April 2024
  • Contact Dermatitis, July 2022, pages 20-27
  • Regulatory Toxicology and Pharmacology, June 2021, ePublication
  • Chinese Journal of Dermatology, December 2020, pages 895-899

Peer-reviewed, substantiated scientific research is used to assess ingredients in this dictionary. Regulations regarding constraints, permitted concentration levels and availability vary by country and region.

Ingredient ratings


Proven and supported by independent studies. Outstanding active ingredient for most skin types or concerns.


Necessary to improve a formula's texture, stability, or penetration.


Generally non-irritating but may have aesthetic, stability, or other issues that limit its usefulness.


There is a likelihood of irritation. Risk increases when combined with other problematic ingredients.


May cause irritation, inflammation, dryness, etc. May offer benefit in some capability but overall, proven to do more harm than good.


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Not rated

We have not yet rated this ingredient because we have not had a chance to review the research on it.