Not An Allergen

PEG-40 Castor Oil

PEG-40 Castor Oil is what is usually used in cosmetics. It is not on published lists of top contact allergens and is not a standard inclusion in patch test trays. That said, there are some things that are good to know and to consider with your contact dermatitis specialist.

First, neither “as is” castor oil nor its hydrogenated or PEGylated variants are toxic. Castor is a plant that produces seeds (beans). Castor oil is produced by pressing ripe seeds that have had their outer covering (hull) removed. The hull, which is part of the seed, contains a deadly poison called ricin. Ricin is a naturally occurring, extremely potent toxin that has no antidote. Castor oil does not contain ricin because ricin does not partition into the oil and is water soluble. In other words, ricin (which is found in the outer part of the seed and is the toxic component) is removed in extraction. The component that is left in the castor oil itself is ricinoleic acid.

While a 2017 study shows that it does seem that there are occasional allergic reactions to Ricinus communis (castor seed oil), “PEGylated and/or hydrogenated derivatives (the latter formerly also available from patch test allergen suppliers) and/or cosmetics containing these specific derivatives did not result in contact allergy or allergic contact dermatitis.” The study continues:

“In our department, castor oil is routinely patch tested ‘as is’, as part of a cosmetic series, but the vast majority of patients (~400 every year, also serving as control patients for the two cases reported here) show no allergic or irritant reactions …

Kalavala et al. previously reported PEG-7 hydrogenated castor oil as a cause of allergic contact dermatitis, and their report suggested that higher molecular weight PEGylated castor oil-derivatives may have less potency to cause allergic contact dermatitis.”

“Contact Allergy to Castor Oil, but Not to Castor Wax,” by Michel Verheyden, Sven Rombouts, Julien Lambert and Olivier Aerts, Department of Dermatology, University Hospital Antwerp

“As is” castor oil is the ethoxylated version of castor oil. This natural oil is used as a fragrance or perfuming agent, which could potentially explain why it might account for more case studies of allergic reactions than the PEGylated variant. PEG-40 castor oil functions as a cleansing and emulsifying surfactant.

When VMV Hypoallergenics lipsticks contain castor oil, we use the PEG-40 variant and our policy is to use larger molecular sizes in our products (no nanoparticles) — a rule of thumb in hypoallergenic formulations: the smaller the molecular size, the higher the risk of an allergic reaction.

Allergic and irritant reactions in lipsticks and lip balms tend to be more from top contact allergens such as dyes, fragrance, and preservatives.

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If you have a history of sensitive skin…

…don’t guess! Random trial and error can cause more damage. Ask your dermatologist about a patch test.

To shop our selection of hypoallergenic products, visit vmvhypoallergenics.com. Need help? Ask us in the comments section below, or for more privacy (such as when asking us to customize recommendations for you based on your patch test results) contact us by email, or drop us a private message on Facebook.

For more:

• On the prevalence of skin allergies, see Skin Allergies Are More Common Than Ever. 
• For the difference between irritant and allergic reactions, see It’s Complicated: Allergic Versus Irritant Reaction.
• For the difference between food, skin, and other types of reactions: see Skin & Food Allergies Are Not The Same Thing. 
• On the differences between hypoallergenic, natural, and organic, check out Is Natural Hypoallergenic? and this video in our YouTube channel. 
• To learn about the VH-Rating System and hypoallergenicity: What Is The Validated Hypoallergenic Rating System?

Main References: 

Regularly published reports on the most common allergens by the North American Contact Dermatitis Group and European Surveillance System on Contact Allergies (based on over 28,000 patch test results, combined), plus other studies. Remember, we are all individuals — just because an ingredient is not on the most common allergen lists does not mean you cannot be sensitive to it, or that it will not become an allergen. These references, being based on so many patch test results, are a good basis but it is always best to get a patch test yourself.

1. Verheyden M, Rombouts S, Lambert J, Aerts O. Contact Allergy to Castor Oil, but Not to Castor Wax. Cosmetics. 2017; 4(1):5. https://doi.org/10.3390/cosmetics4010005
2. Kalavala, M.; Hughes, T.M.; Stone, N.M. Allergic contact dermatitis to polytheylene glycol-7 hydrogenated castor oil. Contact Dermat. 2007, 56, 287–288. [Google Scholar] [CrossRef] [PubMed].
3. DeKoven JG, Silverberg JI, Warshaw EM, Atwater AR, et al. North American Contact Dermatitis Group Patch Test Results: 2017-2018. Dermatitis. 2021 Mar-Apr 01;32(2):111-123.
4. DeKoven JG, Warshaw EM, Zug KA, et al. North American Contact Dermatitis Group Patch Test Results: 2015-2016. Dermatitis. 2018 Nov/Dec;29(6):297-309.
5. DeKoven JG, Warshaw EM, Belsito DV, et al. North American Contact Dermatitis Group Patch Test Results 2013-2014. Dermatitis. 2017 Jan/Feb;28(1):33-46.
6. Warshaw, E.M., Maibach, H.I., Taylor, J.S., et al. North American contact dermatitis group patch test results: 2011-2012. Dermatitis. 2015; 26: 49-59.
7. W Uter et al. The European Baseline Series in 10 European Countries, 2005/2006–Results of the European Surveillance System on Contact Allergies (ESSCA). Contact Dermatitis 61 (1), 31-38.7 2009.
8. Wetter, DA et al. Results of patch testing to personal care product allergens in a standard series and a supplemental cosmetic series: An analysis of 945 patients from the Mayo Clinic Contact Dermatitis Group, 2000-2007. J Am Acad Dermatol. 2010 Nov;63(5):789-98.
9. Warshaw EM, Buonomo M, DeKoven JG, et al. Importance of Supplemental Patch Testing Beyond a Screening Series for Patients With Dermatitis: The North American Contact Dermatitis Group Experience. JAMA Dermatol. 2021 Dec 1;157(12):1456-1465.
10. Verallo-Rowell VM. The validated hypoallergenic cosmetics rating system: its 30-year evolution and effect on the prevalence of cosmetic reactions. Dermatitis 2011 Apr; 22(2):80-97.
11. Ruby Pawankar et al. World Health Organization. White Book on Allergy 2011-2012 Executive Summary.
12. Misery L et al. Sensitive skin in the American population: prevalence, clinical data, and role of the dermatologist. Int J Dermatol. 2011 Aug;50(8):961-7.
13. Warshaw EM1, Maibach HI, Taylor JS, Sasseville D, DeKoven JG, Zirwas MJ, Fransway AF, Mathias CG, Zug KA, DeLeo VA, Fowler JF Jr, Marks JG, Pratt MD, Storrs FJ, Belsito DV. North American contact dermatitis group patch test results: 2011-2012.Dermatitis. 2015 Jan-Feb;26(1):49-59.
14. Warshaw, E et al. Allergic patch test reactions associated with cosmetics: Retrospective analysis of cross-sectional data from the North American Contact Dermatitis Group, 2001-2004. J AmAcadDermatol 2009;60:23-38.
15. Foliaki S et al. Antibiotic use in infancy and symptoms of asthma, rhinoconjunctivitis, and eczema in children 6 and 7 years old: International Study of Asthma and Allergies in Childhood Phase III. J Allergy Clin Immunol. 2009 Nov;124(5):982-9.
16. Kei EF et al. Role of the gut microbiota in defining human health. Expert Rev Anti Infect Ther. 2010 Apr; 8(4): 435–454.
17. Thavagnanam S et al. A meta-analysis of the association between Caesarean section and childhood asthma. Clin Exp Allergy. 2008;38(4):629–633.
18. Marks JG, Belsito DV, DeLeo VA, et al. North American Contact Dermatitis Group patch-test results, 1998 to 2000. Am J Contact Dermat. 2003;14(2):59-62.
19. Warshaw EM, Belsito DV, Taylor JS, et al. North American Contact Dermatitis Group patch test results: 2009 to 2010. Dermatitis. 2013;24(2):50-99.
20. Verallo-Rowell V. M, Katalbas S.S. & Pangasinan J. P. Natural (Mineral, Vegetable, Coconut, Essential) Oils and Contact Dermatitis. Curr Allergy Asthma Rep 16,51 (2016) . https://doi.org/10.1007/s11882-016-0630-9.
21. Park G, Oh DS, Lee MG, Lee CE, Kim YU. 6-Shogaol, an active compound of ginger, alleviates allergic dermatitis-like skin lesions via cytokine inhibition by activating the Nrf2 pathway. Toxicol Appl Pharmacol. 2016 Nov 1;310:51-59. doi: 10.1016/j.taap.2016.08.019. Epub 2016 Aug 22. PMID: 27562088.
22. de Groot AC. Monographs in Contact Allergy, Volume II – Fragrances and Essential Oils. Boca Raton, FL: CRC Press Taylor & Francis Group; 2019.
23. De Groot AC. Monographs in Contact Allergy Volume I. Non-Fragrance Allergens in Cosmetics (Part I and Part 2). Boca Raton, Fl, USA: CRC Press Taylor and Francis Group, 2018.
24. Zhu TH, Suresh R, Warshaw E, et al. The Medical Necessity of Comprehensive Patch Testing. Dermatitis. 2018 May/Jun;29(3):107-111.

Want more great information on contact dermatitis? Check out the American Contact Dermatitis Society, Dermnet New Zealand, the Contact Dermatitis Institute, and your country’s contact dermatitis association.

Laura is our “dew”-good CEO at VMV Hypoallergenics and eldest daughter of VMV’s founding dermatologist-dermatopathologist. She has two children, Madison and Gavin, and works at VMV with her sister CC and husband Juan Pablo (Madison and Gavin frequently volunteer their “usage testing” services). In addition to saving the world’s skin, Laura is passionate about health, inclusion, cultural theory, human rights, happiness, and spreading (like a VMV cream!) goodness!