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Castor oil is most well-known as a home remedy for constipation. But there might be more to this oil than meets the eye.
Castor oil is also frequently touted for its lash-extending properties. While it likely won’t replace lash growth serums, mascara, or eyelash extensions, it might make your eyelashes appear longer or thicker. Whether it actually makes your lashes grow is up for debate.
What is castor oil?
Castor oil is a multi-purpose vegetable oil pressed from the seeds of the Ricinus communis plant.
As a natural remedy, it’s been used as a laxative, anti-inflammatory agent, skin lubricant, and hair growth stimulant. Castor oil has even been used to induce labor during the final days of pregnancy.
Even though castor oil for eyelashes has not been scientifically proven, research has found substances in castor oil (unique fatty acids) have moisturizing properties that might make eyelashes and skin appear healthier.
There’s also evidence that a component of castor oil might be able to prevent hair loss and promote hair and eyelash growth.
Does castor oil actually help eyelashes grow?
Although there is no scientific evidence that castor oil lengthens lashes, there is research showing that some substances it contains may help hair, eyelash, and eyebrow growth. That said, the science behind this isn’t very strong.
Castor oil contains what’s called ricinoleic acid, a substance that blocks the production of something called prostaglandin D2 (PG-D2, for short) in our bodies (Fong, 2015).
Research has shown that PG-D2 is present in high levels in some people who experience hair loss. This lends to the idea that castor oil might help with hair loss, but there isn’t enough proof yet for it to be a routine recommendation (Garza, 2012; Ezekwe, 2020).
Aging, sun exposure, and pollution are a few reasons hair and skin get stressed and become fragile. Castor oil contains a lot of vitamin E, an antioxidant that may help improve hair and skin health (Ananth, 2019; Beoy, 2010).
Using antioxidants on damaged human hair may decrease the breakdown of fibers and help smooth hair cuticles, resulting in improved shine (Fernandez, 2012).
It might be possible that the nourishing properties of castor oil help fight breakage of brittle hair, especially for people who’ve overused things like eye makeup, eyeliners, and waterproof mascara.
How to use castor oil on lashes
Since castor oil is relatively inexpensive compared to commercial eyelash serums, there’s likely no harm in trying it.
Castor oil is generally considered safe to use on skin and hair. It’s usually well-tolerated, but if it causes any irritation it’s a good idea to stop using it. Castor oil has even been used as an ingredient in specially formulated eye drops to treat dry eyes––though you should check with a healthcare provider before trying that (Goto, 2002).
Prices vary, but a bottle of pure castor oil for eyelashes is about $10 on Amazon and comes with little lash wands to make application easy. Many of the reviews are rave, though many customers used the product to grow their brows, not lashes. And of course, using Amazon reviews to pick your products is far from scientific.
Still, even if the only effects are a slightly glossier set of lashes, it’s hard to go wrong.
Potential benefits of castor
As mentioned previously, castor oil contains fatty acids and vitamin E, an important component in many skin and hair products. Both cosmetic and medical uses for vitamin E have positive reports in scientific literature (Keen, 2016).
Studies also suggest other plant oils (like sunflower and argan oils) that contain vitamin E can improve skin health and moisture (Lin, 2018). While there is no definitive data on castor oil specifically, it may serve as a moisturizer for both skin and hair.
Is castor oil safe to use on eyelashes and eyebrows?
Although no studies have been done on using castor oil directly on eyelashes or eyebrows, animal studies show putting castor oil on skin is safe (Jang, 2015).
When castor oil is processed or refined, all toxic elements are removed, resulting in a high-quality oil that can be safely used for medicines or beauty products. The ability of ricinoleic acid to promote hydration has made it a popular ingredient in skincare products, soaps, lipsticks, conditioners, and deodorants (Franke, 2019).
Do a patch test first
Like any other topical cosmetic, castor oil may not work for everyone. To know how your skin reacts to castor oil, a patch test is recommended.
To complete a patch test, use a cotton swab and apply castor oil to a clean, dry area of skin (preferably not on your face). Wait 24 hours to see if your skin reacts with swelling, redness, or itching. Be sure to purchase cold-pressed castor oil from a reputable seller.
How to apply castor oil to eyelashes
Using a small brush or cotton swab, apply a small amount of pure castor oil to the lash line before bed. Or using a clean mascara brush, apply castor oil directly to clean lashes nightly.
If you find that you have itchy or red eyes, flush your eyes with clear water and stop using castor oil on or around your eyes.
Castor oil for eyelashes or hair growth has not been studied thoroughly, and in the United States, the only FDA-approved use for it is as a stimulant laxative (Alookaran, 2021).
The use of castor oil appears promising as a moisturizer and hair loss inhibitor, and there are many people who use it to stop hair loss and promote lash and brow hair growth.
If you have concerns about the condition of your eyelashes or eyebrows, consult with a dermatologist as there may be medical conditions causing lash or brow loss or thinning.
If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
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Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.