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  • Writer's pictureDr. Megan Choy

Castor Oil

Updated: Sep 24, 2023


I recently discovered that castor oil has become a fad, especially on TikTok. I discovered this when a girlfriend of mine started posting about using castor oil packs on her stomach and she's loving the results (https://www.tiktok.com/t/ZPR7N7NvT/). I laughed a little when I saw her post, remembering how I learned about castor oil packs in my first year in naturopathic medical school. It's awesome how these things come around. I love it when I see traditional medicine embraced by a larger group of people!!


So what are these castor oil packs and why do they work? There's a lot of good information out there, and there is some misinformation out there. I want to go over the science, the lore, the traditions, and provide as much information as I can so that castor oil can be used safely and effectively.


The castor oil plant, Ricinus communes, is a tropical flowering plant that was indigenous to Eastern Africa, India, and the southeastern Mediterranean area. The oil is pressed from the bean, or seed, of the castor oil plant. The oil is rich in triglycerides, specifically 90% ricinoleic, 4% linoleic, 3% oleic, 1% stearic, and less than 1% linolenic fatty acids.


The seed does also contain ricin, a highly potent, water-soluble toxin, however, very little of the toxin comes out of the seed into the oil due to its solubility. If you ever come across the plant, the seeds are quite toxic, consuming 4-8 of them is enough to kill an adult. But since, as they say, "oil and water don't mix" the water-soluble toxin does not transfer into the oil, at least not in quantities that would be harmful. There are additional filtration and purification processes that the oil undergoes to ensure no ricin is in the oil. Furthermore, ricin is not especially toxic topically as our water-repellant skin prevents the toxin from entering the body in that way.



As you can see above, ricinoleic acid is the primary compound in castor oil. So what is ricinoleic acid and what does it do? Ricinoleic acid is an omega-9 fatty acid. Omega-9's are a mono-unsaturated fatty acid (MUFA) and are considered non-essential, meaning that the body can synthesize them on its own. However, in the case of omega-9's, the body is unable to synthesize enough for all requirements, so they are actually a partially essential fatty acid. Omega-9s have anti-inflammatory and anti-cancer characteristics. The anti-inflammatory characteristics stem from the ability of omega-9s to alter the production of inflammatory mediators, modulate neutrophil infiltration, and alter vascular endothelial growth factor (VEGF) effector pathways. The anti-cancer characteristics appear to stem from its ability to suppress the migration and proliferation of cancer cells (at least in breast cancer) as well as stimulate tumor suppressor genes. Much of this research is recent and further research is required to better understand these effects and mechanisms.


The effects listed above are for omega-9s generally, with oleic acid (the predominant fatty acid in olive oil) being the best studied. Many of the benefits of omega-9s will apply to ricinoleic acid, but it will have its own areas of specialization. I'm going to simply list off the various benefits of castor oil that I've found as I've been researching this topic. I doubt that this is a comprehensive list. I was surprised to find that most, if not all, of these have scientific research backing. All of them have the backing of long-standing traditional practices. Even the few specific uses (like menstrual cramps) that I couldn't find a scientific study for can be explained by the anti-inflammatory properties.


Topical Uses

  • Anti-inflammatory

  • Antioxidant

  • Antimicrobial (bactericide, antiviral, anti-fungal, anti-parasitic (ringworm))

  • Pain relief (joint pain and others)

  • Reduce masses/anti-cancer

  • Reduce menstrual cramps and bloating

  • Soften adhesions

  • Moisturize skin

  • Wound Healing

  • Soothe dry eyes

  • Treat acne

  • Treats melasma

  • Treats dandruff

  • Promote hair growth

  • Treat nasal polyps

  • Regain sense of smell


Internal (Oral) Uses

  • Induce Labor in Pregnant Women

  • Laxative

Castor Oil Applications

I'm not going to discuss the internal use of castor oil here. This should only be done under the care of a physician to ensure the safety of the patient. So let's talk about the topical uses of castor oil.


Castor oil can simply be applied to the skin. In this way, a small amount of the oil will be absorbed. The oil is also quite thick and sticky and it will stain any fabrics that it comes in contact with. If castor oil is applied to the skin and then rubbed in for 10+ minutes, more of the castor oil will be absorbed. This allows for more therapeutic effect, but does nothing to eliminate the stickiness and staining. The way castor oil is most typically used is in the form of a compress, referred to as a 'castor oil pack.' The castor oil is applied to a fabric, typically an organic cotton flannel. After allowing the oil to soak into the material, the fabric is wrapped around the body part to be treated (abdomen, neck, breast, etc.) and kept on for a few hours or overnight. This allows for a much greater absorption of the oil.


Naval Oiling

One other common application of castor oil is in naval oiling. For this, the oil is put into the belly button and rubbed in. There are some interesting theories about why this works that are floating around social media and TikTok. The one that causes my eyebrows to raise the highest is that "the belly button is connected to 72,000 veins." Before I talk about this, let me say that I suspect there is benefit to be received from naval oiling. However, I don't see any way that the mechanism is what is being described here. It only took me a quick google search to see where people are getting this, it is a direct quotation from an article in Times of India. But let's talk about this. First, even when the umbilicus was connected to the circulatory system as a fetus, it was connected in just a few places, not 72,000. Second, after birth, the connection between the umbilicus and the circulatory system of the body dissolves or disintegrates. You can see from the photo that the belly button is no longer attached to anything in the abdomen in a human adult. So I did a bit of research into the significance of the umbilicus in ayurvedic medicine. What I found is that they talk about 72,000 nadis (energetic channels) that are connected to the umbilicus. This misinformation came from a "lost in translation" event!


With that understanding, I can see why there is a tradition of rubbing oil into the naval. In Chinese medicine as well, the umbilicus is an important location on the body. It is a place to receive nurturing energy, it is an energetically sensitive point on the body. While I have no 'scientific' explanation for this, I see over and over again that energy is important in healing, and I NEVER discount the power of energetic medicine.


Cautions

Used topically, there is little to no risk of overdose or poisoning. Some individuals may have an allergic reaction to castor oil, in which case they should discontinue use.


Taken internally, castor oil can be taken in excess leading to overdose. In fact, castor oil should only be taken internally very sparingly and under physician supervision. Castor oil should be avoided by women during pregnancy unless recommended by a physician to induce labor.


References?

So there is a part of me that really would prefer to provide you with a proper reference section and have citations throughout the post. It would satisfy the scientist and perfectionist in me. It would also make this post take hours longer, possibly preventing me from posting at all because the task would get too large. So this is my compromise. In this section I am going to copy and paste all of the urls of the open tabs in my web browser. This will give you the resources that I used to write this article, and sometimes more.


My open web browser tabs:

  1. https://en.wikipedia.org/wiki/Ricinus

  2. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/castor-oil#:~:text=Castor%20oil%20is%20produced%20by,for%20its%20strong%20laxative%20effect.

  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015816/

  4. https://www.webmd.com/diet/castor-oil-health-benefits#:~:text=More%20than%2090%25%20of%20castor,joint%20pain%20and%20menstrual%20cramps.

  5. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=castor+oil+anti+inflammatory&btnG=&oq=castor+oil+anti

  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3418662/

  7. https://www.scielo.br/j/cta/a/jtzR5bpyvr9Fm6WYDrRqt7t/?lang=en&format=html

  8. https://www.sciencedirect.com/science/article/abs/pii/0378874182900381

  9. https://www.jstage.jst.go.jp/article/jos/71/6/71_ess21226/_article/-char/ja/

  10. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=castor+oil+antioxidant&btnG=

  11. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=castor+oil+skin+moisturizer&btnG=

  12. https://link.springer.com/article/10.2165/01197065-200502040-00006

  13. https://www.sciencedirect.com/science/article/abs/pii/B9780128185537000346

  14. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=castor+oil+wound+healing&btnG=

  15. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=castor+oil+inducing+labor&btnG=&oq=castor+oil+inducing

  16. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=castor+oil+laxative&btnG=

  17. https://www.healthline.com/nutrition/castor-oil#3.-May-promote-wound-healing

  18. https://www.medicalnewstoday.com/articles/319844#use

  19. https://www.health.com/castor-oil-benefits-6827595#citation-5

  20. https://www.ncbi.nlm.nih.gov/books/NBK551626/

  21. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8927560/

  22. https://timesofindia.indiatimes.com/life-style/beauty/what-happens-when-you-start-oiling-your-belly-button/articleshow/82943049.cms#

  23. https://utswmed.org/medblog/belly-button-pain/#:~:text=Why%20do%20we%20have%20belly,developing%20baby%20to%20the%20placenta.

  24. https://www.ncbi.nlm.nih.gov/books/NBK557389/#:~:text=The%20umbilical%20cord%20is%20considered,circulation%20to%20be%20eliminated%20maternally.

  25. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=castor+oil+acne&btnG=

And links for the articles I showed in my TikTok:

  1. https://www.hindawi.com/journals/mi/2000/360629/

  2. https://www.scielo.br/j/cta/a/jtzR5bpyvr9Fm6WYDrRqt7t/?lang=en&format=html

  3. https://www.sciencedirect.com/science/article/abs/pii/S0014299900007275

  4. https://www.sciencedirect.com/science/article/abs/pii/S037851731400948X

  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8963633/#:~:text=Some%20studies%20reported%20the%20association,and%20costs%20can%20be%20reduced.

  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4302680/

  7. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=constipation+inflammatory&btnG=#d=gs_qabs&t=1695586746584&u=%23p%3D9Rkvozq2hRAJ

  8. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=diarrhea+inflammatory&btnG=#d=gs_qabs&t=1695586852616&u=%23p%3DTWGJSg0ybp0J

  9. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=infammation+IBS&btnG=#d=gs_qabs&t=1695586936107&u=%23p%3DP5olxrvFoSoJ

  10. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=gall+stones+inflammation&btnG=#d=gs_qabs&t=1695587017104&u=%23p%3D1P1_D4sWcp0J

  11. https://acrjournals.onlinelibrary.wiley.com/doi/epdf/10.1002/art.38794

  12. https://acrjournals.onlinelibrary.wiley.com/doi/abs/10.1002/art.23755

  13. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C29&q=brain+tumor+inflammation&btnG=#d=gs_qabs&t=1695587194110&u=%23p%3DSnoK2fDw8-4J

  14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3492709/#:~:text=Inflammation%20has%20long%20been%20a,perhaps%20even%20all%20of%20them.

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