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The Science of Castor oil in Skin Care Products

Geschrieben von: Dr. Leslie Baumann

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Lesezeit 7 min

Castor oil has become a popular ingredient in many skin care products, but what exactly is castor oil and how does it benefit the skin? In this blog, we'll explore the components and properties of castor oil that make it an effective ingredient for dry, oily, aging, and acne-prone skin. We'll also overview proper usage and any risks. Read on to learn more about harnessing the power of castor oil in skin care based on your unique Baumann Skin Type.

What is Castor oil?

What is Castor oil?

Castor oil comes from pressing the seeds of the castor plant, whose scientific name is Ricinus communis L. of the Euphorbiaceae family. (3) The castor plant is native to tropical regions like China, India, and Brazil. (3)

Castor oil has been used commercially for various industrial purposes like lubricating airplane engines, manufacturing dyes, detergents, and varnishes. (3) In skin care, castor oil is used for its beneficial skin lipids and phenolic antioxidant compounds. (3)

What is castor oil made of?

The main component of castor oil is the triglyceride fatty acid called ricinoleic acid, making up almost 90% of the oil. (2) Ricinoleic acid is unique in that it's a hydroxylated fatty acid produced when oleic acid is chemically modified. (5)

Other fatty acids found in smaller quantities in castor oil include linoleic acid, oleic acid, linolenic acid, palmitic acid, and stearic acid. (2) Linoleic and linolenic acids are anti-inflammatory and moisturizing for skin. The oil also contains antioxidants like vitamin E, carotenoids, phospholipids, and beta-sitosterol. (3)

What is Ricinoleic acid?

What is Ricinoleic acid?

Ricinoleic acid is a monounsaturated 18-carbon fatty acid, structurally similar to oleic acid with the addition of a hydroxyl group. This shape gives ricinoleic acid the ability to break apart fats. (It's an emulsifier). (5)

Ricinoleic acid also has pain killing and anti-inflammatory effects. It acts on inflammation similar to capsaicin, the active component in hot chili peppers. However, unlike capsaicin, ricinoleic acid doesn't cause any initial stinging or burning. (6) With repeated use over several days, ricinoleic acid reduces inflammation and swelling. (7)

Benefits of Castor oil in Skin Care

The ingredients in castor oil offer a number of benefits that make it effective for various skin types and conditions:

  • Ricinoleic acid has anti-inflammatory properties that can calm irritation and redness. (4, 6, 7)
  • Ricinoleic acid provides mild pain relief. (4, 6)
  • Castor oil has antibacterial properties to combat acne-causing bacteria. (8)
  • The fatty acids help nourish and moisturize the skin barrier. (2)
  • Vitamin E and other antioxidants protect against free radical damage. (3)
  • Castor oil helps treat skin conditions like hyperpigmentation. (2)
  • It can be used to manage blepharitis (eyelid inflammation) when applied in an eye cream. (1)

Here are some of my favorite castor oil products in general:

Side-effects of Castor oil

Castor oil is generally safe to use topically. The EWG (Environmental Working Group) gives castor oil a safety rating of 2, which is a great score. Pregnant women should also avoid consuming castor oil unless advised by a doctor, as it may potentially stimulate labor. (10)

When applying castor oil to the skin, use only a small amount as it can feel greasy in excess. Discontinue use if any irritation develops. 

Castor oil for dry skin

The hydrating and quick working fatty acids in castor oil make it an excellent moisturizer for dry skin types. The ricinoleic acid provides a soothing effect for flaky, irritated skin. Castor oil's thick consistency allows it to form an occlusive barrier on the skin, preventing moisture loss.

Look for castor oil in hydrating serums, creams, oils, and masks to combat dryness. You can also apply a light layer of pure cold-pressed castor oil onto dry areas as an overnight treatment. Focus on dry spots like the hands, heels, elbows, and any cracked skin.

Here are some of my favorite castor oil products for dry skin:

Castor oil for oily skin

Although castor oil has a greasy texture, it can still benefit oily and acne-prone skin when used properly. The antimicrobial activity of castor oil can destroy acne-causing bacteria on the skin. (8) Ricinoleic acid helps reduce inflammation that leads to breakouts.

When acne-fighting ingredients like salicylic acid or benzoyl peroxide cause dryness, using moisturizers with castor oil can boost hydration without clogging pores. Oily skin types should opt for cleansing oils with castor oil to remove makeup and dirt while maintaining moisture.

Here are some of my favorite castor oil products for oily skin:

Castor oil for aging skin

Castor oil contains fatty acids and vitamin E to nourish aging skin and combat dryness, which is common during menopause. The antioxidants in castor oil also protect mature skin against wrinkle-causing free radicals that accumulate with age.

For sunspots and uneven tone, dab castor oil on hyperpigmented areas to fade discoloration thanks to its ability to inhibit melanin production.

Here are some of my favorite anti-aging castor oil products:

Castor oil for acne

Castor oil can be beneficial for acne-prone skin when used in moderation. The antimicrobial properties make castor oil a great addition to acne cleansers. (8) Ricinoleic acid calms the inflammation that leads to breakouts.

When using castor oil for acne, don't use a pure castor oil product, as the thick texture can clog pores. It can safely be one of many ingredients for acne-prone skin, but the palmitic acid in it means there is a small risk of comedones. Check that your skin tolerates castor oil before applying all over the face.

Here are some of my favorite castor oil products for acne prone skin:

Castor oil for inflammation

One of the main benefits of castor oil is its ability to reduce inflammation. The ricinoleic acid soothes irritation and swelling on contact. Applying castor oil can calm inflammatory skin conditions like eczema and psoriasis.

Castor oil also eases the pain of sunburns due to the analgesic effect of ricinoleic acid. Castor oil can be put into soothing aloe vera gel for sunburn relief. 

Here are some of my favorite castor oil products for inflammation:

Closing thoughts

Castor oil has many benefits for skin thanks to its nourishing fatty acids, antioxidants, and antimicrobial properties. Ricinoleic acid calms inflammation that underlies many skin ailments like acne, eczema, and sun damage. Castor oil provides intense hydration for dry skin while maintaining a balanced moisture level for oily skin prone to breakouts.

When shopping for skin care products, look for castor oil on the ingredients list to target your specific skin needs. With various uses for all skin types, castor oil can enhance skin care routines year-round. Let us know about your experience with castor oil in the comments!

Take the Baumann Skin Type quiz today to find out if castor oil is right for you!

Level up your skin care knowledge with medical advice from dermatologists

Best References and Scientific Publications on Castor oil in skin care

  1. Muntz, A., Sandford, E., Claassen, M., Curd, L., Jackson, A. K., Watters, G., ... & Craig, J. P. (2021). Randomized trial of topical periocular castor oil treatment for blepharitis. The ocular surface19, 145-150.

  2. Parvizi, M. M., Saki, N., Samimi, S., Radanfer, R., Shahrizi, M. M., & Zarshenas, M. M. (2023). Efficacy of castor oil cream in treating infraorbital hyperpigmentation: An exploratory single‐arm clinical trial. Journal of Cosmetic Dermatology.

  3. Yeboah, A., Ying, S., Lu, J., Xie, Y., Amoanimaa-Dede, H., Boateng, K. G. A., ... & Yin, X. (2020). Castor oil (Ricinus communis): a review on the chemical composition and physicochemical properties. Food Science and Technology41, 399-413.

  4. Vieira, C., Evangelista, S., Cirillo, R., Lippi, A., Maggi, C. A., & Manzini, S. (2000). Effect of ricinoleic acid in acute and subchronic experimental models of inflammation. Mediators of inflammation9, 223-228.

  5. James, A. T., Hadaway, H. C., & Webb, J. P. (1965). The biosynthesis of ricinoleic acid. Biochemical Journal95(2), 448.

  6. Vieira, C., Evangelista, S., Cirillo, R., Terracciano, R., Lippi, A., Maggi, C. A., & Manzini, S. (2000). Antinociceptive activity of ricinoleic acid, a capsaicin-like compound devoid of pungent properties. European journal of pharmacology407(1-2), 109-116.

  7. Vieira, C., Fetzer, S., Sauer, S. K., Evangelista, S., Averbeck, B., Kress, M., ... & Manzini, S. (2001). Pro-and anti-inflammatory actions of ricinoleic acid: similarities and differences with capsaicin. Naunyn-Schmiedeberg's archives of pharmacology364, 87-95.

  8. 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 Science71(6), 781-793.

  9. Conforti, C., Giuffrida, R., Fadda, S., Fai, A., Romita, P., Zalaudek, I., & Dianzani, C. (2021). Topical dermocosmetics and acne vulgaris. Dermatologic Therapy34(1), e14436.

  10. Azhari, S., Pirdadeh, S., Lotfalizadeh, M., & Shakeri, M. T. (2006). Evaluation of the effect of castor oil on initiating labor in term pregnancy. Saudi medical journal, 27(7), 1011.
  11. Baumann L. Antiaging Ingredients in Ch. 37 of Baumann's Cosmetic Dermatology Ed 3. (McGraw Hill 2022)
  12. Baumann, L. Ch. Cosmeceuticals and Cosmetic Ingredients (McGraw Hill 2015)