Is It Good for Hair, Skin, Digestion, Childbirth, and More?

By Brittany Lubeck, RD 

Updated on July 02, 2023

 Medically reviewed by Beth Thomas, PharmD

Claims of castor oil benefits include that it may be used as a laxative, aid in childbirth and labor, relieve arthritis pain, and moisturize skin.

A vegetable oil derived from the seeds of the castor bean plant, castor oil is also known as Ricinus communis. The main active component of castor oil is ricinoleic acid, a type of fatty acid shown to possess anti-inflammatory properties.¹

This article looks at the suggested benefits of castor oil and possible side effects, precautions, interactions, and dosage.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLabs, or NSF. 

However, even if supplements are third-party tested, that doesn’t mean they are necessarily safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.

Supplement Facts

• Active ingredient(s): Ricinoleic acid

• Alternate name(s): Ricinus communis, riccinus oil

• Legal status: Legal in the U.S. and available over-the-counter (OTC)

• Suggested dose: There are no universal dosage requirements for castor oil.

• Safety considerations: Side effects, like abdominal cramping, bloating, and dizziness, are possible when using castor oil.²

Uses of Castor Oil

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

While castor oil has long been used both orally and topically in traditional medicine, research on its potential benefits is limited. Additionally, study results regarding its health effects have been inconsistent.

That said, castor oil continues to be touted as a treatment for a wide variety of conditions from headaches to menstrual cramps.

Below is a look at what is known about some of castor oil's most popular uses.

Laxative

The Food and Drug Administration (FDA) has approved castor oil for only one medical use: to serve as a stimulant laxative. In fact, castor oil is often used to treat constipation or prep the bowels for various medical procedures.³ However, it may not work as well as some other laxatives.

Ricinoleic acid is thought to be responsible for the laxative properties of castor oil. Once digested, castor oil is broken down into ricinoleic acid, stimulating the bowels through a series of reactions.⁴

Research has shown that castor oil is an efficient way to cleanse the bowels for procedures such as a colonoscopy. However, the studies conducted have been small; randomized trials with control groups are necessary to prove that castor oil is effective.⁵

Can Castor Oil Melt Body Fat?

Castor oil does not reduce body fat. Some people claim that drinking about 1 tablespoon of castor oil regularly can help lower weight and body fat. According to some proponents of the practice, castor oil suppresses your appetite, which naturally leads you to eat less and lose weight. However, no studies have been conducted indicating that castor oil affects body weight or body fat.

The laxative properties of castor oil can lead to a small immediate weight loss, but this should not be confused with long-term body fat reduction. Laxatives should not be used for weight loss.⁶

Hair and Skin Care

Despite numerous claims, there is no strong evidence that castor oil can stimulate hair growth.

Some people apply castor oil topically to the scalp and hair as a hair conditioner to treat dandruff or to make hair shiny. While some research has found that castor oil might improve the appearance of hair by increasing its luster, this evidence, too, is fairly weak and not conclusive.⁷

 What You Need to Know About Using Coconut Oil for Your Hair

Some people also use castor oil for skin care treatment for wrinkles and dry skin. Castor oil is considered an occlusive moisturizer, which means it creates a barrier to protect the skin and locks in moisture to prevent dry skin.⁸

However, while other plant oils have been well investigated for potential skin benefits, castor oil has not. This means that any skin benefits of castor oil have yet to be scientifically proven.

Labor Induction

It has long been claimed that castor oil can induce labor. But studies investigating this claim have shown mixed results.

An observational, retrospective study looked at the use of castor oil to induce, or initiate, labor. The study took place over five years and included women between 40 and 41 weeks pregnant, which is full-term. Compared with the control group, the women who used castor oil showed a higher probability of going into labor within 24 hours.⁹

Another study involved 612 women whose pregnancies lasted longer than 40 weeks. Of these women, 205 received castor oil for induction of labor. The study's authors found that the time to birth was not significantly different between those who took the oil and those who did not.¹⁰

w-ings / Getty Images

Arthritis

Castor oil has been studied for potential use in relieving symptoms associated with osteoarthritis of the knee.¹¹

In the study, men and women over 40 with knee osteoarthritis took capsules containing castor oil or diclofenac sodium (a nonsteroidal anti-inflammatory drug) three times daily for four weeks.

The results indicated that both treatments were effective at relieving pain associated with osteoarthritis. In the diclofenac sodium group, 90% of participants showed significant improvement in pain levels, while 92% of those in the castor oil group showed significant improvement in arthritis-associated pain.

The study authors noted that the findings were significant because no side effects were associated with the use of castor oil. But in the diclofenac sodium group, about 20% of participants complained of mild gastritis (inflammation of the stomach lining), and 4% of participants complained of skin rashes.¹¹

Antibacterial

Research has shown that castor oil contains antibacterial properties that make it appropriate to apply to a wound. The potassium salt in castor oil appears to control infection and promote healing.¹²

In addition to caring for wounds, castor oil can be used to remove bacteria from material. Studies have specifically focused on its effectiveness in removing bacteria from dentures, ensuring better overall health for denture wearers.¹³

What Are the Side Effects of Castor Oil?

It's important to be aware of potential side effects before starting a new supplement or medication. Like most supplements, side effects are possible when using castor oil. These side effects may be mild or severe.

Common Side Effects

Mild side effects have been reported with the use of castor oil. Typically, these and other side effects will subside once castor oil use stops.

Common side effects of castor oil may include:¹⁴

• Nausea

• Vomiting

• Abdominal pain or fullness

• Thirst

• Dizziness

• Diarrhea

• Anal irritation

• Insomnia

In addition to some evidence showing that castor oil may cause a skin rash, there is research showing it may be unsafe to use on your hair and scalp.

One study discovered a rare condition called acute hair felting, where the hair became hard, twisted, and entangled. These symptoms occurred following the use of castor oil for the first time by healthy individuals.¹⁵

Severe Side Effects

According to the National Institutes of Health (NIH), swallowing too much castor oil can be harmful. It is possible to overdose on castor oil, which could cause severe consequences.

Signs of castor oil overdose, which warrants immediate medical attention, include:¹⁶

• Abdominal cramps

• Chest pain

• Diarrhea

• Dizziness and fainting

• Hallucinations

• Nausea

• Shortness of breath

• Skin rash

• Throat tightness

Some of these are similar to the common side effects associated with castor oil, so it is important to take it exactly as directed. Talk with your healthcare provider about the right dose of castor oil for you.

Precautions

Castor oil may not be right for everyone, and there are a few precautions to take when using it.

It is recommended that people who are pregnant avoid using castor oil, as it could cause premature contractions.¹⁶

There is not enough research to know if castor oil is safe for breastfeeding people. Because of this, you should consult your healthcare provider before using castor oil. Also, parents should consult their pediatrician before giving castor oil to children.

It's possible to be allergic to the castor plant, as contact dermatitis has been reported in rare cases after using topical castor oil. Therefore, anyone allergic to castor oil should avoid using it.¹⁷

Ricin, a substance in castor beans, is also important to note. Ricin is a potent toxin derived from part of the waste mash produced when beans from the castor plant are processed to make castor oil. It is contained in the hull of the bean, which is discarded in the oil manufacturing process. This means it does not make its way into the end product.

Ricin made news when letters containing the toxin were sent to members of Congress and the White House in 2018. According to the Centers for Disease Control and Prevention (CDC), unintentional exposure to ricin is highly unlikely, except through the ingestion of castor beans.¹⁸ However, if you suspect exposure to ricin, the agency recommends that you seek medical help immediately.

Dosage: How Much Castor Oil Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs. 

Castor oil may be used orally or topically in varying amounts. Due to a lack of research, there are no official recommendations for the dosage of castor oil.

In adult males, an appropriate castor oil dose is 15 to 60 milliliters (mL) a day when used as a laxative.³ However, this range may not be suitable for everyone. You should follow dosage recommendations from your healthcare provider or as listed on the supplement label.

Taking too much castor oil may cause side effects, so it's important to talk with your healthcare provider about the right dosage for you.

What Happens if I Take Too Much Castor Oil?

It is possible to take too much castor oil, which may cause various side effects.

Generally, castor oil is thought to be safe and non-toxic when used in appropriate amounts. But it is possible to overdose on it.¹⁶

The castor oil plant, Ricinus communis, contains ricin, which is a known toxin. Fortunately, the ricin is removed from the castor bean in making castor oil. However, large amounts of castor oil are thought to be poisonous.¹⁶

You should seek immediate medical attention if you think you have overdosed on castor oil. Signs of a castor oil overdose include but are not limited to:¹⁶

• Stomach cramps

• Chest pain

• Hallucinations

• Fainting

• Shortness of breath

• Skin rash

• Throat tightness

Because it is possible to overdose on castor oil, you should talk with your healthcare provider to determine the proper dosage and instructions for use.

Interactions

Oftentimes, supplements may interact with various medications or other supplements. In the case of castor oil, drug or supplement interactions are not well-documented.

Aside from the lack of evidence, interactions with castor oil may still exist. You should discuss any potential interactions between castor oil and the medications or supplements you're taking with your healthcare provider.

It is vital that you carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included. Please review new supplement labels with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications. 

How to Store Castor Oil

Supplements should be stored properly to avoid spoiling. Keep your castor oil supplements in a cool, dry place. They should also be stored out of direct sunlight.

Be sure castor oil and other supplements are out of the reach of children and pets in your home. Discard castor oil supplements once they reach their expiration date as listed on the packaging.

Similar Supplements

Various supplements may work similarly to castor oil. However, it is typically recommended to avoid using multiple supplements for the same purpose at a time. Talk with your healthcare provider about which supplements are best for you.

Similar supplements to castor oil include:

• Black cohosh: Black cohosh has traditionally been used by midwives for natural labor induction. However, it is recommended that pregnant people use black cohosh with caution and speak with their healthcare provider before using it.¹⁹

• Magnesium: Some magnesium supplements, like magnesium oxide, are thought to work like laxatives. After ingestion, magnesium helps pull water to the bowels, an important part of stool formation. It is often used as a laxative in the clinical setting due to its safety.²⁰

• Vitamin D: Vitamin D has been found to have many benefits for human health, including skin health. Studies have shown that dry skin is related to low levels of vitamin D in the body. Because of this, using vitamin D supplements is thought to improve skin hydration.²¹

• Boswellia: Also known as Indian frankincense, Boswellia has been used for the treatment of osteoarthritis. One systemic review looked at several studies and found Boswellia could relieve pain associated with osteoarthritis. The supplement was also found to be a safe option.²²

No supplement should replace standard medical care. Always seek medical guidance from a healthcare provider to discuss the right supplement choice.

Sources of Castor Oil and What to Look For

Castor oil is not widely found in foods and is mostly used in supplement form.

Castor Oil Supplements

Castor oil can be used either orally or topically. It is available as a serum, soft gel, or oil.

Some castor oil supplements are cold-pressed and unrefined, while others are a bit more processed. Typically, castor oil supplements are both vegan and gluten-free.

It is recommended that you look for a reputable castor oil brand and, if possible, buy from a familiar vendor such as your local pharmacy. It's also important to read the castor oil label carefully, as potentially irritating fragrances are sometimes added.

Summary

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease. 

Many people think of castor oil as a treatment for constipation. However, it has also been studied for other potential uses, like inducing labor, relieving arthritis pain, and moisturizing skin. Many of these claimed benefits of castor oil are not well-supported by evidence.

Castor oil supplements can cause side effects, including diarrhea, abdominal cramps, nausea, rash, and even hallucinations, in some cases. You should be aware of any precautions or interactions associated with castor oil, and talk with your healthcare provider before using it.