What is Hydrogenated Castor Oil ?

Pure castor oil can provide a number of benefits for our health and wellness. But hydrogenated castor oil is a buzzword you may be less familiar with. What is hydrogenated castor oil? What are it’s uses, and how does it stack up against pure castor oil?

what is hydrogenated castor oil

So What is Hydrogenated Castor Oil?

Hydrogenated castor oil, also known as castor wax, is a hardened vegetable wax produced from pure castor oil through the chemical process of hydrogenation. When hydrogen is introduced to pure castor oil in the presence of a nickel catalyst, the resulting product becomes waxy, highly viscous, and more saturated.

Hydrogenated castor oil is an ingredient prevalently found in many cosmetics, varnishes, and polishes. You most likely use it on a daily basis. Unlike pure castor oil, which is said to have a slightly offensive smell, it is completely odorless. Hydrogenated castor oil is also insoluble in water.

But why hydrogenate castor oil when the pure oil works so well for so many different applications? What is the purpose of hydrogenating castor oil, exactly?

Hydrogenated Castor Oil Uses?

The purpose of the hydrogenation process is to improve castor oil’s melting point, texture, odor, and shelf-life.

hydrogenated castor oil

Once hydrogenated, the resulting castor oil product is comprised of hard, brittle flakes. Hydrogenated castor oil is considered an organic ingredient, as well as a vegan one, as it is vegetable-derived.

One application of hydrogenated castor oil is to improve certain cosmetic products. You can add the flakes to cosmetic formulations until thoroughly melted. In this capacity, hydrogenated castor oil acts as an emollient and a thickener; increasing the viscosity of creams, ointments, and lotions when their composition is too runny.

Hydrogenated castor oil also stabilizes cosmetics that come in stick-form (like lipstick) and increases these products’ melting points, making for a more stable product. In part thanks to hydrogenated castor oil, it’s not the end of the world if we leave a tube of red lipstick in a hot car! Hydrogenated castor oil means our lipsticks maintain a solid structure even when they’re pushed to the limit, and our deodorant doesn’t crumble as we apply it.

What Products Contain Hydrogenated Castor Oil?

You will often find hydrogenated castor oil in the following cosmetic products:

  • Lotions
  • Creams
  • Ointments
  • Deodorants
  • Foundations
  • Lipsticks
  • Lip balms
  • Anything in “stick” form

HCO gives some of our favorite products the texture, consistency, and stability we love.

hydrogenated castor oil in cosmetics


Of course, just like pure castor oil, hydrogenated castor oil is incredibly versatile. Cosmetics are not the only products that benefit from its properties. HCO is also frequently present in the production of:

  • Rubbers
  • Waxes
  • Paints
  • Polishes
  • Varnishes
  • Crayons
  • Candles
  • Lubricants
  • Sealants
  • Carbon paper
  • Electrical capacitators
  • Polyurethane
  • …and more

Hydrogenated castor oil is especially present in these types of products when something requires resistance to moisture and oils, such as in polishes, varnishes, and paints.

What is PEG-40 Hydrogenated Castor Oil?

PEG-40 Hydrogenated Castor Oil is the polyethylene glycol (PEG) derivative of hydrogenated castor oil. It’s uses are common in this form as an emulsifier and a fragrance ingredient.

PEG-40 has the FDA-approval for external use. Studies have found PEG-40 to be safe in concentrations of up to 100%. Generally speaking, PEGs are not skin irritants. PEG-40’s molecular weight of 40 means it is only minimally absorbed into the skin.

hydrogenated castor oil in industry

However, there is quite a bit of controversy over the safety of PEG-40. While the FDA approved it for external use, the Cosmetics Database found it to be moderately hazardous. According to the database, contamination is possible with potentially toxic impurities. Studies show that applying products containing PEG-40 to severe burns can result in kidney toxicity. So never apply to broken skin due to the risk of organic toxicity.

How can PEG-40 be so toxic when absorbed by the body when pure castor oil is so safe? To understand that, we need to look at the scientific process of ethoxylation.

PEG-40 is a result of the ethoxylation process. When hydrogenated castor oil is ethoxylated with ethylene oxide, which is a petroleum-based chemical, the process may introduce the carcinogen 1,4 dioxane as a contaminant. It also may not. This is a possibility each time the ethoxylation process occurs. However, it is not a guarantee that the product result is without contamination.

The Bottom Line: Is Hydrogenated Castor Oil Safe?

Like everything else we purchase and use, hydrogenated castor oil and PEG-40 contain both pros and cons. It is up to you to decide what is right for you, your body, your home, and your family.

Scientifically, hydrogenating castor oil is considerably safe. Even PEG-40 seems to be generally safe with only a low-to-moderate risk of contamination. Whenever possible, though, we recommend the pure form of castor oil over any derivative.

With PEG-40, you never know if it might contain contaminating carcinogens. You are simply trusting the product’s manufacturer. Simply, contaminants do not need to be visible on product labels. So why take the risk?

Exercise caution and always research before you buy any product. Know that just because something has a “natural” label doesn’t mean it doesn’t contain potentially harmful or toxic chemicals.

Always be a smart and savvy consumer and research any ingredients that seem foreign to you on your cosmetics, food, and otherwise.


  1. Susan Rekieta said:

    Hi Brittany,
    Thank you for your informative post. I was wondering if you have a recommendation for a substitute for Peg 40. I have a lotion recipe that I am going to make but just do not feel comfortable using Cremophor CO 40. The recipe calls for 3/4 of an ounce.
    Kind Regards,

    November 2, 2017
    • Hi Susan,
      Thanks so much for reaching out to me and for your patience while I respond to an increasing amount of requests! Thanks for your comment. I am not as familiar with substitutes, however, but if your concern is with the safety then I would recommend double checking your recipe’s source. It’s an intricate question, so I’d prefer not to give you advice of which I am unsure of. According to this site, some substitutions may be possible. Please click here to read it. I wish you all the best! I’m sorry I could not offer you the answer you were looking for exactly. Thanks in any case for reading my article and for your encouraging words. All the best,

      November 20, 2017

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