Monday, December 14, 2009

Castor oil

Castor oil (INCI Ricinus communis (castor) seed oil) is an oil with a very interesting fatty acid profile. It contains about 2 to 6% oleic acid (C18:1), about 4% linoleic acid (C18:2), and 85 to 95% ricinoleic acid (C18:2, w-9). It is a very thick, pale coloured oil with very little taste. In fact, it is so thick that on one scale if soy bean oil has a viscosity of 29 and olive oil a viscosity of 47, castor oil has a viscosity of 293! This is one of the reasons it is used so much in cosmetic creations!

Castor oil is soluble in alcohol and creates an interesting solubility with beeswax, which is why it is used so much in lipsticks, lip balms, and deodorants. It has a low molecular weight so it penetrates skin easily, and acts as a softening oil. It is a greasy feeling oil with a lot of shine, but can feel sticky (again, this is why it is used so much in lipsticks - it's shiny and it works to keep the oil on your lips and not feathering into fine lines). It is low comedogenic (1 out of 5) and non-irritating. It has acanthotic activity, meaning it can help increase skin thickness.

Ricinoleic acid is an interesting fatty acid. It's a hydroxy acid, which is why it is soluble in alcohol (but not water) and oil. It's a humectant (look at those lovely OH groups!), which is another reason we see it so often in cosmetic products! The ricinoleic acid makes it both a drier type of oil and increases the viscosity of the oil.

Castor oil is an inexpensive oil with a shelf life of up to one year. It is a softening oil but can feel dry on your skin. It is considered a very thick oil - one of the thickest at the homecrafter's disposal - so you might want to save it for those times you really need some serious softening and moisturizing. Castor oil does contain some phytosterols in the form of ß-sitosterol, campesterol, and stigmasterol, so it does offer some anti-inflammatory and itch reducing properties. It doesn't appear to have much in the way of Vitamin E, so you might want to include a titch if you are planning to keep your product around for more than a year! The ricinoleic acid is considered an analgesic and anti-bacterial, and there are some indications it might act as an anti-fungal oil. (Hence the use for a lot of foot products!)

If you're interested in trying the oil cleansing method (OCM) for your face, consider using between 30 to 50% castor oil in an anhydrous mixture of various oils. It's a great addition in a product you want to be water resistant, like a lip stick or zinc oxide, or a heavy feeling moisturizer that will sink into your skin without occluding it. The anti-inflammatory and anti-microbial features might be a good addition for a facial product if you're having trouble with acne - it's low on the comedogenicity scale, so it shouldn't annoy sensitive skin too much.

As an aside, castor seeds contain ricin, which is incredibly poisonous. One seed could kill a child, 6 can kill a horse, 6 to 20 to could an adult, and 80 can kill a duck or a rooster (which really just goes to show that the dose really does make the poison!)

Castor oil is also considered a good laxative, but considering you need about 30 ml to be effective, you don't need to worry much about a lipstick with this oil! (You'll probably use something like 2 or 3 ml maximum in a lip balm, and you're not going to eat all of it in one day, right?)

As a note, you can buy sulfated castor oil, also known as turkey red oil, which is a surfactant that can be used an emulsifier in things like bath oils and bath bombs. I'll be writing more about this ingredient when I get into emulsifiers!

Join me tomorrow for a few ideas on formulating with castor oil.


Stacy said...

First, I LOVE your blog! I'm just starting a business and your blog is my first go-to for resources and information, so thank you! I hope I don't sound crazy by asking this, but is there any danger whatsoever using Castor Oil in massage cream/oil mixtures? I assume that the pressing process eliminates any chance of unsafe traces of ricin the oil, but the thought is crossing my mind. Thanks for your time, Stacy

Susan Barclay-Nichols said...

Hi Stacy. It's all good. And I've used your comment in today's Weekend Wonderings because I'm sure others have asked the same question!

Bonnie said...

Hey Susan. I bought Peg-40 Hydrogenated Castor Oil, which comes in a soft solid form. Will this have the same effect as the liquid castor oil? Also, what's the best beeswax / castor oil ratio to get that tackiness ?

Susan Barclay-Nichols said...

Hi Bonnie. Check out the link on the PEG-40 hydrogenated castor oil. It's a solubilizer, so it is completely different to castor oil. I'm not sure of the ratio necessary for the castor oil/beeswax as it has to be checked every time you make it because of the differences in each batch of castor oil and beeswax wax. I've seen recipes for mock Vaseline with a 94/6 ratio, so you'll want a higher percentage of beeswax than that.

Maria Miller said...

Hi Susan,

I was just browsing for a beginning formula that used castor oil, beeswax and water. I want to create a hair moisturizer with those ingredients but I want it to be an emulsion where I can add water based ingredients like humectants, extracts, etc. My concern is if I can use an emulsifier along with the beeswax. I am currently using CreamMaker fluid (hlb 11) and for long term stability a small amount of Sorbitan Tristearate (hlb 2.1).

Thanks for your help in advance.

Susan Barclay-Nichols said...

Hi Maria. Why would you make a moisturizer for your hair with those ingredients? What does each one bring to the product? You can use an emulsifier with this product to make a lotion - follow the directions of those emulsifiers from the company that supplied them.

Note: Beeswax is NOT an emulsifier. It is an oil soluble ingredient that can be emulsified along with all the other oils, butters, and so on.

Can I make a sugestion? This is a not-so-great combination for hair. The beeswax brings nothing to the hair and will be very hard to remove, creating build up and weighing your hair down, and the castor oil will moisturize your scalp and create a film on your hair, but it won't penetrate. The water will not mix with the other ingredients without an emulsifier. If you are making something for your hair, a cationic or positively charged emulsifier is the best choice as it will offer conditioning and substantivity to your hair, while a non-ionic one won't. Check out the hair care section of the blog for more information.

Anonymous said...

I find it interesting that Castor Oil is considered 'drying' to skin because I massage it all over my face, under my eyes, on my arms, legs and body before going to bed at night (just a titch, which does actually soak into my skin) and then I let it rinse off in the shower the following morning.

After I step out of the shower, dry and dress, I find that my skin has a 'slippery soft' feeling to it (only way I can describe it) - so soft, it makes a baby's skin seem rough.

I don't need to use a moisturizer as a result and my skin looks 'dewy' and fresh.

Also, the night before I wash my hair (it's hip length, thick and dry on the ends), I massage the tiniest bit of castor oil into the length of my hair (it absorbs very well), brush it through, leave it in overnight, then shampoo and condition as normal in the morning.

Makes my damaged and chemically treated hair feel like healthy, bouncy, shiny, very soft virgin hair. Again, it's hard to describe the dramatic change in my hair thanks to organic castor oil.

So as a result, I do find some of the negative comments and various 'warnings' about castor oil being 'drying', rather perplexing. I've not found that to be the case at all - quite the contrary, in fact but then again, I do use organic castor oil although I can't imagine that would have anything to do with it.