Carrier Oil Profile: Castor Oil
Monday, November 19, 2018
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
|
81
|
|
Oleic Acid
|
9
|
|
Linoleic Acid
|
5
|
|
Stearic Acid
|
3
|
|
Others
|
2
|
Table Source: https://shop.skinchakra.eu/en/Cosmetic-Lab/Plant-oils-butters-and-waxes/Castor-oil-organic-cold-pressed.html
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).
References:
Castor
Oil. Retrieved from https://swiftcraftymonkey.blog/castor-oil/
Castor
Oil. Retrieved from https://www.anandaapothecary.com/castor-oil
Saponification
Chart. Retrieved from https://www.fromnaturewithlove.com/resources/sapon.asp
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