Which castor oil benefits are backed by science?
Social media influencers swear by castor oil for curing blurry vision, busting belly fat, and even killing tumors. But what does it actually do for the body?
Castor oil gets tons of attention on social media. Countless videos tout its purported health benefits, from relieving constipation to promoting hair growth and breaking down belly fat.
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 it 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 it as a laxative, to treat various eye and skin conditions, and to induce labor, among other things.
But scientists have learned much about the oil since then. While some of these modern claims are fairly innocuous, others may put your health at risk. So, which castor oil claims are grounded in science?
What is castor oil used for?
Castor oil is a vegetable oil made from the seeds of the castor oil plant, which is indigenous to the Mediterranean, North Africa, and India. Communities in those areas have used castor oil for constipation and to stimulate birth for millennia. The seeds are also called castor beans, which are poisonous if the outer shell is broken and the bean is ingested.
(Arsenic pills and lead foundation: The history of toxic makeup)
Offermanns thinks the oil’s noticeable laxative effect is one reason it has been around so long. He was among the first to study how ricinoleic acid in castor oil causes muscle contractions.
By studying mice, he found that the 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.
(Drinking chlorophyll is a popular wellness trend. Does it really work?)
The U.S. Food and Drug Administration (FDA) 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 it can be safely used to induce birth. However, the evidence has been more mixed, and the oil does not have FDA approval for that purpose, Offermanns says.
(Why women are more likely to have IBS)
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.
Additionally, 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 castor oil has many downsides. When it comes to other uses, it can be downright dangerous.
(The secret to a healthy gut is simpler than you think)
Castor oil to reduce belly fat
Many popular videos show people applying 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.
(Some call it ‘nature’s Ozempic.’ Are the claims too good to be true?)
“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 Memorial Sloan Kettering Cancer Center.
(New research shows how genes can identify risks of breast cancer)
Wohlford adds that while putting castor oil on your stomach only comes with a low risk of skin issues, drinking it 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 adds that if weight loss is your goal, the best way to go about it is to develop healthy, sustainable habits.
(Cortisol rises during intense workouts. Is that really a bad thing?)
Castor oil to improve skin
The effect of castor oil on the skin can be positive. Nina Botto, an associate professor of dermatology at the University of California, San Francisco, says the biggest castor oil benefit for skin is hydration.
(Vitamin C, retinol, biotin? Here’s what your skin actually needs.)
The same is true for other oils, too. But while it has antimicrobial properties and is less likely to irritate the skin than other oils like olive or citrus, 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 any amount of castor oil on your face every night won’t reduce wrinkles, as some have claimed. Researchers have yet to find evidence that castor oil, or any oil, has anti-aging effects.
(‘Superagers’ seem to share this one key personality trait)
Castor oil to treat 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. Instead, 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 the oil can’t seep into the eyeball—it only sits on the surface.
(No food or medicine can do what olive oil can do. Here’s why.)
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 may cause infection, resulting in vision loss, Al-Hashimi says. Castor oil can contain things like perfumes and preservatives, which can cause irritation.
(Why are so many children being diagnosed with myopia?)
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.
(What is methylene blue and can it really boost your brain power?)
Talk to your doctor
Even though castor oil continues to be touted as a cure-all, experts say it’s not that simple. 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.
(Are you taking the wrong medications? You might be surprised.)
Even as a laxative, castor oil can cause side effects and intestinal damage. Often, that’s an unnecessary risk given there are other, better laxatives out there, Offermanns says.
Still, scientists continue to research the benefits and drawbacks. In the future, they may have more evidence as to what castor oil can—and cannot—do for us.
