If you’ve been on social media recently, you’ve likely heard of castor oil. There are countless videos of influencers touting its benefits—claiming the oil can improve vision, break down belly fat, detoxify the body, get rid of wrinkles, and much more.
Castor oil is “one of the oldest drugs,” says Stefan Offermanns, a professor of pharmacology at Goethe University, Frankfurt, and a director at the Max Planck Institute for Heart and Lung Research. Scientists have discovered castor oil in Egyptian tombs dating back to 4000 B.C. An ancient Egyptian medical text called the Ebers Papyrus, dating to 1550 B.C., shows that early physicians prescribed castor oil as a laxative, to treat various eye and skin conditions, and to induce labor, among other things.
But scientists have learned a lot about castor oil since then. While some of these modern claims are fairly innocuous, others might put your health at risk. So, which castor oil claims are grounded in science?
What is castor oil—and what is it actually good for?
Castor oil is a vegetable oil made from castor beans, which are the seeds of Ricinus communis, the castor oil plant. The plant is indigenous to the Mediterranean, North Africa, and India, where communities have used castor oil as a laxative and to stimulate birth for millennia.
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Offermanns thinks that castor oil’s noticeable laxative effect is one reason it has been around so long. He was among the first to study how ricinoleic acid—the active ingredient in castor oil—causes muscle contractions. By studying mice, he found that castor oil works on the EP3 receptor, a prostaglandin receptor that is found in several areas of the body, including the gut and cervix. Stimulating this receptor causes muscle contractions, leading the body to push out stool or induce cervical contractions that kickstart the birthing process. Mice that lacked the receptor didn’t experience these effects.
The U.S. Food and Drug Administration has approved castor oil for use as a laxative, meaning that it’s safe and effective to use for this reason. Several studies have also looked at whether castor oil can be safely used to induce birth, but the evidence has been more mixed, and the oil does not have FDA approval for that purpose, Offermanns says.
Still, Offermanns says he probably wouldn’t recommend his patients take castor oil for its laxative effects because there are more effective laxatives on the market with fewer side effects like nausea and vomiting. Plus, studies show that consistently taking castor oil can cause irritation and damage to the intestinal lining. This goes for all laxatives—misusing laxatives is likely to cause serious damage to the gut and other organs over time, Offermanns adds.
But when it comes to other uses, castor oil might be ineffective or downright dangerous.
Stomach and belly button
Many popular videos show people smearing castor oil on their stomachs and inside their belly buttons, claiming that doing so can get rid of belly fat, improve gut health, and “detoxify” the body. But those assumptions are not rooted in science, says University of Texas MD Anderson Cancer Center program manager and wellness dietician Lindsey Wohlford.
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“Unfortunately, most of these are claims, anecdotes, or personal testimonies, but they’re not based on any type of science or solid research,” she says, explaining that castor oil isn’t absorbed through the skin and into the body—so putting it on your skin is unlikely to affect your internal organs.
This also means castor oil can’t treat tumors close to the surface of the skin, like breast tumors, as some have claimed. “There’s just absolutely no evidence of that,” says Jun Mao, chief of the Integrative Medicine Service at the Memorial Sloan Kettering Cancer Center.
Wohlford adds that while putting castor oil on your stomach only comes with a low risk of skin issues, drinking castor oil is riskier.
“When we’re talking about safely losing weight, any weight loss method that is unproven has the risk of being not only unsafe and ineffective, but also a waste of someone’s money and time,” Wohlford says.
Wohlford says that if weight loss is your goal, the best way to go about it is to develop healthy, sustainable habits.
Skin care
For the skin, castor oil can have positive effects. Nina Botto, an associate professor of dermatology at the University of California, San Francisco, says that the biggest benefit castor oil offers the skin is hydration.
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The same is true for other oils, too. But while castor oil is less likely to irritate the skin than oils like olive or citrus oils—plus it has some antimicrobial properties—Botto says it’s not the first product she would recommend to patients. For people with acne-prone skin, castor oil can clog pores and worsen acne. But “there are certainly much worse [oils],” she says.
Additionally, Botto says that spreading castor oil on your face is unlikely to reduce wrinkles, as some have claimed. Researchers have yet to find evidence that castor oil, or any oil, has anti-aging effects.
Eye problems
Experts say there’s no scientific evidence backing claims that castor oil can cure eye problems like blurry vision or help your eyelashes grow longer—and that people who have vision problems should talk to their physician.
“You only have two eyes and you need to take care of them,” says Saba Al-Hashimi, an associate clinical professor of ophthalmology at UCLA’s Stein Eye Institute. “There’s not any great evidence to suggest that [castor oil] can help with things like glaucoma or improving vision.” That’s because these conditions are often inside the eye, and castor oil can’t seep into the eyeball—it only sits on the surface.
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In fact, studies have found that some people experience eye irritation and blurry vision after taking eye drops containing castor oil. Eyedrops require rigorous amounts of sterility and regulation to be considered safe to use, and sometimes homeopathic products don’t meet those standards. Putting unsterilized castor oil on your eye might end up causing an infection, resulting in vision loss, Al-Hashimi says. Castor oil can contain things like perfumes and preservatives, which can cause irritation.
Castor oil may have some promise as a dry-eye treatment, according to a small number of studies, and it is already an ingredient in some products. Scientists are also interested in researching castor oil because some patients prefer nonsynthetic eyedrops. But Al-Hashimi stresses that this doesn’t mean you should start putting castor oil in your eyes. “I hesitate to endorse the use of a preparation of castor oil that is not manufactured for ophthalmic use and not regulated by the FDA,” he says.
Talk to your doctor
Even though castor oil continues to be touted as a cure-all, experts say that it’s not that simple—and that it’s always safest to consult with your doctor. For example, Mao points out that castor oil could cause complications or unexpected interactions if you’re also taking other drugs.
Even as a laxative, castor oil can cause side effects and intestinal damage—often an unnecessary risk given there are other, better laxatives out there, Offermanns says.
Still, scientists continue to research the benefits and drawbacks of castor oil—and, in the future, they may have more evidence as to what castor oil can and cannot do for us.
