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IUPAC name
Butyl 4-hydroxybenzoate
Other names
Butyl paraben;
Butyl parahydroxybenzoate;
Butyl p-hydroxybenzoate
3D model (JSmol)
ECHA InfoCard 100.002.108
Molar mass 194.23 g·mol−1
Appearance Colorless, odorless, crystalline powder
Melting point 68 to 69 °C (154 to 156 °F; 341 to 342 K)
Slightly soluble
Solubility in acetone, ethanol, chloroform, glycerin, propylene glycol Soluble
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oilHealth code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Butylparaben, or butyl p-hydroxybenzoate, is an organic compound with the formula C
.[1] It is a white solid that is soluble in organic solvents. It has proven to be a highly successful antimicrobial preservative in cosmetics.[2] It is also used in medication suspensions, and as a flavoring additive in food.

Natural occurrence[edit]

Members of the paraben family are found in fruit and vegetable products, such as barley, flax seed, and grapes.[3] Butylparaben has also been found to be produced in some microorganisms including Microbulbifer .[4]


Butylparaben is prepared by the esterification of 4-hydroxybenzoic acid with 1-butanol in the presence of an acid catalyst such as sulfuric acid.[5] It is produced industrially.

Uses and reactions[edit]

Butylparaben is one of the most common bactericidal/fungicidal additives in cosmetics. It has been used in cosmetic products since the 1940s and in pharmaceutical products since 1924.[6] The popularity of butylparaben in these products is due to its low toxicity in humans and its effective antimicrobial properties, in particular those against mold and yeast.[7] It is now found in more than 20,000 cosmetic products including eye shadow, facial moisturizer/treatment, anti-aging cream, foundation, and sunscreen.[8] It is also used as low-ionic strength solutions as a preservative in some foods and drugs.[5] In most cosmetics paraben is used at low levels, ranging from 0.01 to 0.3%.[9] Butylparaben is used in low concentrations in liquid and solid medication suspensions, such as Tylenol (acetaminophen) and ibuprofen.[10]

Mechanism of action[edit]

The exact mechanism of how parabens work is unknown but they are proposed to act by inhibiting DNA and RNA synthesis, and enzymes like ATPase and phosphotransferase in some bacterial species. It has also been suggested that they interfere with membrane transport processes by disrupting the lipid bylayer and possibly causing the leakage of intracellular constituents.[11]

Regulation and controversy[edit]

Butylparaben has not escaped controversy, which itself is controversial.[12][9][13]

In December 2010 the Scientific Committee on Consumer Products (SCCP) of the European Union reported that insufficient data is available to perform risk assessments for butylparaben in humans.[14] The committee has also stated that it considers the use of butylparaben and propylparaben as preservatives in finished cosmetic products as safe to the consumer, as long as the sum of their individual concentrations does not exceed 0.19%.[1]


Denmark restricts butylparaben in products for use by children younger than the age of three.[14]

In 2003, butylparaben was approved for use as a flavor additive in food by the U.S. Food and Agriculture Organization and the World Health Organization.[1][15] Butylparaben is also regulated by the United States Environmental Protection Agency under the U.S. Toxic Substances Control Act of 1976 and the Federal Insecticide, Fungicide, and Rodenticide Act. Its pesticide registration was canceled in 1998.[1]

Endocrine disruption[edit]

Long-chained parabens, like butylparaben, are more estrogenic than short-chained parabens, like methyl- or ethylparaben. This difference is attributed to the greater lipophilicity of the former.[14] Butylparaben displayed the most competitive binding to rat estrogen receptors when tested along with methyl, ethyl, and propylparabens.[16]


Butylparaben can decrease sperm function and alter metabolic hormones.[14] Rats exposed to a high concentration of butylparaben during pregnancy gave birth to fewer pups, and pups with malformed reproductive organs.[1] Mice administered butylparaben at 0.01-1% body weight for ten weeks showed a decrease in serum testosterone concentration and in spermatid counts in the seminiferous tubules.[1]


It has been shown that butylparaben enter the body through the lungs, GI tract, and skin epithelium.[1]

It occurs in breast cancers at around 20.6±4.2 ng/g tissue.[1] However, parabens have not been proven to cause breast cancer.[9] Estimates by the U.S. Food and Drug Administration and the Center for Food Safety and Applied Nutrition have found that the average person is exposed to about 37 ng of butylparaben per day.[1]

Butylparaben has been found in small concentrations in human breast fat and breast tumors.[1] A review by the National Toxicology Program concluded, "There is no evidence of demonstrable risk for the development of breast cancer caused by the use of paraben-containing underarm cosmetics."[17] Animal studies have been inconclusive. Oral administration of butylparaben to eight-week-old rats has caused tumors such as thymic lymphoma, non-thymic lyphoid leukemia, and myeloid leukemia.[1] Similar studies, however, have found no significant increase in tumors upon butylparaben administration.[1] Butylparaben is not listed as a carcinogen by the International Agency for Research on Cancer.[18]

Environmental fate[edit]

Butylparaben has been found in the sewage. A 2001 study found that concentrations of parabens in Danish sewage facilities was to 100 to 1000 times below the acute or chronic effect concentrations.[19]


  1. ^ a b c d e f g h i j k "Butylparaben Review of Toxicological Literature" (PDF). National Toxicological Program. April 2005. Archived from the original (PDF) on 2011-10-21.
  2. ^ Philip A. Geis "Preservation strategies" in "Cosmetic Microbiology, A Practical Approach" Edited by Philip A. Geis, CRC Press 2006. Pages 163–180, Print ISBN 978-0-8493-1453-7, eBook ISBN 978-1-4200-0332-1 doi:10.3109/9781420003321-12
  3. ^ "Parabens". Vashon Organics. Retrieved 2011-10-31.
  4. ^ Peng, X; Adachi, K; Chen, C; Kasai, H; Kanoh, K; Shizuri, Y; Misawa, N (2006). "Discovery of a Marine Bacterium Producing 4-Hydroxybenzoate and Its Alkyl Esters, Parabens". Applied and Environmental Microbiology. 72 (8): 5556. doi:10.1128/AEM.00494-06. PMC 1538717. PMID 16885309.
  5. ^ a b "Butylparaben". Hazardous Substance Data Bank. February 2004.
  6. ^ "Parabens as Preservatives" (PDF). UENO FINE CHEMICALS INDUSTRY LTD. Archived from the original (PDF) on 2012-04-25. Retrieved 2011-10-31.
  7. ^ "Parabens as Preservatives" (PDF). UENO FINE CHEMICALS INDUSTRY LTD. Archived from the original (PDF) on 2012-04-25. Retrieved 2011-10-31.
  8. ^ Anon, "Final Amended Report on the Safety Assessment of Methylparaben, Ethylparaben, Propylparaben, Isopropylparaben, Butylparaben, Isobutylparaben, and Benzylparaben as used in Cosmetic Products", Int. J. Toxicol. 2008, 27, 1.
  9. ^ a b c "Parabens". U.S. Food and Drug Administration. Archived from the original on 2011-10-30. Retrieved 2011-10-31.
  10. ^ "Ibuprofen Suspension". FreshPatents.com. Retrieved 2011-10-31.[permanent dead link]
  11. ^ Valkova, N; Lépine, F; Valeanu, L; Dupont, M; Labrie, L; Bisaillon, JG; Beaudet, R; Shareck, F; Villemur, R (June 2001). "Hydrolysis of 4-Hydroxybenzoic Acid Esters (Parabens) and Their Aerobic Transformation into Phenol by the Resistant Enterobacter cloacae Strain EM". Applied and Environmental Microbiology. 67 (6): 2404–9. doi:10.1128/AEM.67.6.2404-2409.2001. PMC 92888. PMID 11375144.
  12. ^ Castelain, F., Castelain, M., "Parabens: a real hazard or a scare story?", Eur. J. Dermatol. 2012, 22, 723. doi:10.1684/ejd.2012.1835
  13. ^ "EWG's Skin Deep Cosmetics Database". Environmental Working Group. Retrieved 2011-10-31.
  14. ^ a b c d "Parabens used in personal care products and cosmetics". Chem Sec International. Archived from the original on 2012-04-23. Retrieved 2011-10-31.
  15. ^ "35th Session of the Codex Committee on Food Labeling". Biodiversity Policy and Practice. 2003.
  16. ^ "Pharmaceuticals and Personal Care Products in the Environment: Agents of Subtle Change?" (PDF). Environmental Health Perspectives. Retrieved 2015-02-08.
  17. ^ "Butylparaben [CAS No. 94-26-8]: Review of Toxicological Literature" (PDF). National Toxicology Program, National Institutes of Health. April 2005.
  18. ^ "Agents Classified by the IARC Monographs, Volumes 1–109" (PDF). International Agency for Research on Cancer.
  19. ^ "The Royal Danish School of Pharmacology Annual Report 2001" (PDF). The Royal Danish School of Pharmacology. 2001.