Castor oil is commonly used as a food additive and in the manufacturing of various other items including commercial hair products, soaps and skin cosmetics. It is rich in ricinoleic acid, a fatty acid that may have anti-inflammatory, antimicrobial, and pain-relieving abilities.
Castor oil is a vegetable oil that’s made from the seeds of Ricinus communis, a plant commonly known as the “castor oil plant” that’s found across Africa, India, and tropical regions around the globe. The oil ranges in hue from pale-yellow to colourless and has a “nauseating taste,” according to PubChem, an open chemistry database maintained by the National Institutes of Health (NIH).
Depending on the use, castor oil can be applied to the skin topically or ingested orally.
Cultures around the world have used it for thousands of years as a remedy for a variety of conditions and ailments, per the U.S. Department of Agriculture (USDA).
“A long time ago, people used castor oil because they thought it would make them healthier. They would take a tablespoon of it every day before they really understood too much about it,” says Kathryn Boling, MD, a family medicine physician at Mercy Personal Physicians at Lutherville, Maryland.
But recently, the public’s interest in its purported benefits has surged, thanks in large part to coverage on social media. More than 783 million views were dedicated to #castoroil on TikTok as of August 29, 2023, and nearly 264,000 posts appeared on Instagram. Online influencers claim that castor oil works as a treatment for everything from constipation to cellulite reduction.
But how accurate are these assertions? Here’s an overview of what research has to say about some of castor oil’s most touted uses:
8 POSSIBLE USES FOR CASTOR OIL
1. Laxative for Constipation
The U.S. Food and Drug Administration (FDA) has approved castor oil for one medicinal use: as a stimulative laxative for the relief of occasional constipation, according to StatPearls. The oil is expected to produce a bowel movement within 6 to 12 hours when taken orally, according to the National Library of Medicine’s DailyMed database.
Research on elderly patients who have chronic constipation has shown that castor oil can reduce straining during a bowel movement and create softer stools.
And in a study published in the World Journal of Gastrointestinal Pharmacology and Therapeutics, researchers reported that when castor oil was added to the standard medication prep for a capsule endoscopy — a procedure in which a tiny camera takes pictures of your digestive tract — it helped clean the bowels more thoroughly.
“It’s definitely one of the things you could take that would help you with constipation, but it doesn’t taste very good. There are a lot of other treatments out there for constipation,” says Dr. Boling.
Castor oil use for constipation has declined over the years as more effective options have become available, per StatPearls. Additionally, there may be some side effects which include abdominal cramping, vomiting, bloating, and dizziness.
If you do wish to try castor oil for constipation, it’s best to first discuss this with your doctor. The drug label suggests a dosage of between 1 and 4 tablespoons for adults and children older than 12, taken for just one week, per DailyMed.
2. Labour Inducer
Throughout history, pregnant women have taken castor oil to try to induce labour. While this method was once considered customary, many doctors warn against castor oil’s unpleasant side effects, such as nausea, vomiting, and diarrhoea. Some research also suggests the use of castor oil to induce laboir may increase the baby’s risk of passing meconium (the first bowel movement) before birth, which can be harmful.
“I would say, don’t take it to make your labour start. I don’t think it’s safe,” says Boling. “Maybe if I was in a country with no medical resources and I was desperate, and castor oil was the only thing available, I might take it. But otherwise, there are many better [evidence-supported] options.”
Castor oil is believed to help induce labour via its laxative effects, which could irritate the uterus. “If you stimulate the uterus, either by rubbing it with your hand or by your intestines being super active, that could prompt you to have some contractions,” explains Boling.
While some preliminary research suggests women who are 40 to 41 weeks pregnant who take castor oil have a greater chance of going into labour within 24 hours, other research has shown that women at 40 or more weeks who took castor oil did not give birth any sooner than those who had no oil.
3. Denture Cleaner
Dentures can harbour a lot of bacteria and fungi, so keeping them clean is important. Some research suggests that castor oil may be an effective way to keep dentures in tip top shape.
A lab study published in Brazil Oral Research found that soaking a bacteria and fungi-contaminated mould resembling a denture in a 10 percent castor oil solution reduced some of the contamination but wasn’t as effective in removing the fungi and bacteria as a sodium hypochlorite solution.
A study published in the Journal of Applied Oral Science showed that brushing and soaking dentures in a castor oil solution did however, lead to reductions in candida, a fungal infection caused by yeast.
4. Cellulite Cure
If it sounds too good to be true, it just might be. While some online influencers and posters have made anecdotal claims that castor oil can eliminate cellulite, Boling says there’s no evidence to back them up.
“This is what I tell my patients: When there’s something that gets rid of cellulite, you’ll know, because you’ll look around and see that no one will have any,” says Boling. “But until that happens, there is nothing that’s going to get rid of it.”
Despite the lack of published research supporting the topical use of castor oil to treat cellulite, some people still believe that massaging the oil onto lumpy, dimpled areas of the skin can improve circulation, which they believe reduces the appearance of cellulite.
5. Arthritis Remedy
Castor oil may provide relief for people who suffer from arthritic pain. “Arthritis is inflammatory; that’s what makes it hurt. You have inflammation,” explains Boling. “So anything that has an anti-inflammatory in it, such as castor oil, [may] help with arthritis.”
In one study, participants with knee osteoarthritis took capsules containing castor oil or diclofenac sodium (a drug used to treat arthritis) three times a day for four weeks.
Results showed both groups experienced comparable and significant improvements in arthritis pain levels. But the people in the castor oil group reported fewer side effects.
Other research has suggested that applying castor oil topically may reduce joint pain and inflammation.
6. Skin Hydrator
While there’s no proof that castor oil can erase all wrinkles, as some online accounts profess, the oil does have properties that can help lock in moisture and keep your skin hydrated.
Castor oil is commonly used in many cosmetic products, such as lotions and cleansers, but the research on its benefits for skin is relatively limited.
According to one study review, fatty acids found in castor oil may enhance smoothness and softening of the skin.
Additionally, the authors note that the oil may promote an increase in healthy pores and skin tissue via its moisturising, cleansing, and hydrating abilities.
Castor oil can be used on its own or mixed with another oil, such as coconut oil or almond oil, prior to applying. Because castor oil can be irritating and may cause an allergic reaction in some people, it’s a good idea to test a small area of the skin before using it all over.
7. Eye Soother
About 20 million people in the United States are living with dry eye disease, according to the American Academy of Ophthalmology. Some research suggests that castor oil may help relieve symptoms of this common condition. What’s more, castor oil is commonly used as an ingredient in many eye drops.
A small study showed that an eye drop formula containing castor oil, created especially for the study, lessened symptoms of dry eyes by producing a more stable tear film.
And the Clinical and Experimental Optometry review concluded that castor oil can relieve clinical signs and symptoms of dry eye but recommended further research be done to determine its effectiveness.
While some online accounts have suggested placing castor oil directly in the eye, experts recommend against this advice. Be sure to talk to your healthcare provider if you’re thinking about using castor oil for dry eye symptoms. Your doctor can tell you which products are safe and effective.
8. Hair Grower
You may have seen videos online promoting the use of castor oil for thicker hair, fuller eyebrows, or longer lashes. Despite various anecdotal claims, there’s no solid scientific evidence proving that castor oil can stimulate hair growth. In fact, a review of research examining various natural products did not find any evidence to support the use of castor oil to treat hair loss.
“It’s not going to regrow hair, unfortunately,” says Boling.
However, some people use castor oil on their hair to lubricate and moisturise their scalp. This could potentially be helpful if you have dry, irritated skin on your head. Some online posts mention massaging a few drops of castor oil directly into the scalp for a couple of hours to help alleviate dryness.
THE BOTTOM LINE
For years, castor oil has been used as a beauty hack or medicinal remedy for various ailments. Recently, online social media platforms have sparked a renewed interest in the oil’s benefits, though the claims aren’t always true or supported by published research. While castor oil has been approved by the FDA for limited use in relieving constipation, there’s no solid and consistent evidence at this time showing it can definitely help with anything else mentioned above. If you want to add castor oil or any other supplement to your diet or skincare routine, Boling says that it’s always a good idea to talk to your doctor first.