Therapeutic uses of castor oil
By Jillian Jastrzembski
Castor oil has an almost magical appeal in the alternative medicine community, along with growing interest in mainstream healthcare. You likely have heard castor oil touted for hair loss, abdominal pain, constipation, menstrual pain, joint pain, and many other ailments.
In this article, we’re talking about the various uses of castor oil – and there are many. How is castor oil being used today? What is the clinical and scientific evidence to support its efficacy? And what is the biochemical mechanism behind these therapeutic properties?
What is castor oil?
Castor oil is derived from the castor oil plant, otherwise known as Ricinus communis. It is originally native to Africa and India, and now grown worldwide on an industrial scale.
The castor oil is extracted from the bean of the plant via solvent extraction and cold pressing. The major constituent of the resulting pale-yellow oil is ricinoleic acid, which accounts for up to 90% of the chemical composition. Other fatty acids are present to a lesser degree, including oleic, linoleic, and palmitic acids, as well as their glycosidic derivatives.
Ricinoleic acid itself is an unsaturated fatty acid with three different functional groups, including a single alkene, one alcohol, and one carboxylic acid. It has both hydrophilic and lipophilic components, which lend themselves to this molecule’s versatility. The variety of functional groups means that ricinoleic acid can participate in many different chemical reactions. As a result, castor oil has a range of valuable properties.
Uses of Castor Oil
Castor oil has a long history of therapeutic use, and remains today in many traditional herbal pharmacopeias. Documented medical use dates back to at least 1500 BC in ancient Egypt. Castor oil has also been found in tombs dating back at least 5000 years.
Additionally, the body of scientific research validating the use of castor oil for medical and therapeutic applications is growing. Today, topical and/or oral castor oil may be used for:
- Cosmetics/ personal care products
- Drug delivery systems
- Wound dressing
- Polymeric materials
- Tissue engineering
- Bioadhesives
- Traditional herbal pharmacopeias
- Food manufacture
- Hair growth
- Ophthalmic treatments
- Labor induction
- Laxative
A popular way to apply castor oil topically is in the form of castor oil packs, which also widely available as kits. A towel or cloth is soaked with castor oil and heat is applied (for example, via a heating pad). This is a traditional therapy for ailments such as menstrual issues, abdominal pain, pregnancy and postpartum complications, constipation, and more. Evidence for efficacy is mainly anecdotal and clinical.
So far there is limited scientific research on this therapy. There is some scientific evidence that castor oil packs can relieve symptoms of constipation in the elderly.
Castor oil may also be used internally. Again, although there is a long history of clinical use, scientific studies are still lacking. There is some evidence that castor oil can be used to induce labor in low-risk late-term pregnant women. As we’ll see, the mechanism for its efficacy is also reasonably well-defined.
Properties of Castor Oil
Castor oil boasts a long list of valuable properties including:
- Anti-microbial
- Anti-inflammatory
- Anti-nociceptive
- Analgesic
- Antioxidant
- Wound healing
- Vasoconstricting
- Anti-fungal
- Anti-herpetic
Biochemical basis of castor oil therapy
A key feature of ricinoleic acid is that its chemical structure is similar to the prostaglandin family. Prostaglandins are hormone-like chemicals produced in the body which have key biological functions. They play a role in menstruation and ovulation, labor induction, blood flow, inflammation, and repair.
As such, drugs that resemble prostaglandins are often useful for the treatment of health conditions. Because of its structural similarity to prostaglandins, ricinoleic acid can interact with prostaglandin receptors. It is therefore relevant in a variety of physiological pathways. For example, this explains the ability of castor oil to act as a laxative, and to induce uterine contractions.
The prostaglandin-like action of castor oil may also contribute to hair growth, wound healing, and skin regeneration. Another useful feature of castor oil is its antimicrobial action. Antimicrobials can target the cell wall of bacteria, ultimately leading to cell death. This isn’t purely attributed to the presence of ricinoleic acid, but also thanks to some of the minor constituents, such as glycosides.
The antioxidant capacity of castor oil is largely attributed to ricinoleic acid, its methyl esters, tocopherols, and tocotrienols. Even at trace levels, many of these compounds are effective in inhibiting and repairing oxidative stress.
Conclusion
Castor oil is a popular remedy from ancient times that still finds therapeutic relevance today. It has a multitude of valuable healing properties including anti-microbial, antioxidant, analgesic, and anti-inflammatory. Castor oil is used topically and orally to treat gynecological disorders, gastrointestinal organs, and to promote general healing. The efficacy of castor oil is largely attributed to its primary component, ricinoleic acid, which resembles prostaglandins, and is thus able to influence a variety of biochemical pathways.
References
Arslan, G. G., & Eşer, I. (2011). An examination of the effect of castor oil packs on constipation in the elderly. Complementary therapies in clinical practice, 17(1), 58–62. https://doi.org/10.1016/j.ctcp.2010.04.004
Gilad, R., Hochner, H., Savitsky, B., Porat, S., & Hochner-Celnikier, D. (2018). Castor oil for induction of labor in post-date pregnancies: A randomized controlled trial. Women and birth : journal of the Australian College of Midwives, 31(1), e26–e31. https://doi.org/10.1016/j.wombi.2017.06.010
Nitbani, F. O., Tjitda, P. J. P., Wogo, H. E., & Detha, A. I. R. (2022). Preparation of Ricinoleic Acid from Castor Oil:A Review. Journal of oleo science, 71(6), 781–793. https://doi.org/10.5650/jos.ess21226
Sandford, E. C., Muntz, A., & Craig, J. P. (2021). Therapeutic potential of castor oil in managing blepharitis, meibomian gland dysfunction and dry eye. Clinical & experimental optometry, 104(3), 315–322. https://doi.org/10.1111/cxo.13148
