Carrier Oil Profile: Castor Oil

Monday, November 19, 2018

Carrier Oil Profile: Castor Oil
Image Source: Craftology Essentials

INCI Name: Ricinus communis (Castor) Seed Oil
Source: Castor beans
Types: Refined / Unrefined
Color: Clear yellow
Aroma: Neutral smell
Viscosity: Very thick
Absorption: Slow
Comedogenic Rating: 1
Shelf Life: 2 years (if stored in cool, dry place and away from direct sunlight)
SAP Value (for soap making): 176 - 186 (mg KOH), NaOH = 0.129 (g, oz or lb), KOH = 0.181 (g, oz or lb)
Ideal for which skin type: oily, acne-prone skin
Fatty Acid Profile (in %):

Ricinoleic Acid
Oleic Acid
Linoleic Acid
Stearic Acid

Castor oil is extracted from castor beans, often via cold-pressed method. It has a very thick and sticky consistency (like a corn syrup) and has slow absorption rate. It is also a highly glossy oil which explains why it is often use in lip products (e.g. lip gloss) to add some shine and to achieve wet-look lips.

There are two types of castor oil: refined and unrefined. Actually, there isn’t that much distinction between the two types in terms of color and scent. The only difference is that the refined version has longer shelf life but has less beneficial properties.

In terms of fatty acid profile, castor oil has high amount of ricinoleic acid which is not found in other vegetable oils. Ricinoleic acid is a monounsaturated omega-9 fatty acid which possesses analgesic (painkilling), anti-inflammatory, antimicrobial, antibacterial and antifungal properties. It is also a hydroxy acid – a type of acid that is often found in chemical peeling products to reduce the appearance of wrinkles and fine lines. The hydroxy acid content of castor oil makes it a suitable ingredient for anti-aging skincare products. Ricinoleic acid also makes castor oil a humectant which attracts moisture from the atmosphere and binds it to our skin to make it hydrated.

The castor beans (where castor oil is derived) contain a toxic substance called ricin. In fact, it is so poisonous that it’ll only take one castor bean to kill a child. Luckily, castor oil doesn’t contain ricin. It’s because ricin is water soluble (won’t mix with oil) and it is deactivated when heat is applied during the oil extraction process. Yes, even cold-process extraction uses low heat so the poisonous substance won’t be present at all in castor oil.

Castor oil is more suitable for people with oily and/or acne-prone skin. It’s anti-inflammatory and antibacterial properties can help prevent the growth of pimple-causing bacteria. Castor oil is also an astringent so it can tighten and shrink enlarged pores, as well as reduce excess oil on your skin. Moreover, it has a low comedogenic rating of 1 which means that it has a low chance of clogging your pores. Even though castor oil is highly moisturizing (due to its low molecular weight that makes it penetrates deep into the skin), it is not recommended for dry skin because of its astringent properties which can further dry out the skin.

Castor oil is a common ingredient in color cosmetic products (e.g. lipstick, liquid foundation, etc.) because its high viscosity can disperse pigments (e.g. iron oxide) evenly compared to other vegetable oils. In fact, when you buy oil soluble liquid pigments, they are often a mixture of castor oil and iron oxide.

There has been some speculations floating around the internet saying that castor oil can promote hair growth, which is evident by the number of DIY eyelash serum recipe with castor oil as the primary ingredient. In reality, (as of this writing) there are no strong scientific evidences or studies conducted supporting this claim. Those who have personally experienced hair growth through the use of castor oil might be attributed to a placebo effect, so the result could be a bias. However, this does not mean that castor oil doesn’t have any good effects on hair. Aside from being a hair conditioner, the antifungal property of castor oil can help get rid of dandruff.

In cold process soap making, castor oil boosts lather (bubbles) and cleansing action due to its ability to draw out dirt out of your skin. Use not more than 5% of castor oil in your soap formulation because more than that amount will cause the soap to be sticky.

Castor oil is also a natural laxative so it can be used to relieve constipation. Since it’s considered as stimulant laxative, it’s not recommended for long term usage. Also, don’t worry if your lip products have castor oil. The amount of castor oil in lip products are not adequate enough to induce bowel movement.

Because of its thick and sticky consistency, castor oil is typically blended with other carrier oils at 5 – 20% of the total formulation (whether it’s for skin or hair products).


Castor Oil. Retrieved from

Saponification Chart. Retrieved from

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