Table of Contents

• What are the effects of castor oil?
• Castor Oil: Effects on skincare & wound healing
• Castor Oil: Effects on hair & scalp care
• Castor Oil: Effects on eyelashes & eyebrows
• Castor Oil: Effects on lips & nails
• Castor Oil: Effects on the beard
• How do castor oil packs work?
• Castor Oil: Effects of the Pechoti Method (Pechoti Drop)
• How does castor oil affect digestion?

What are the effects of Castor Oil?

Castor Oil can inhibit germs, reduce inflammation, and protect the skin from moisture loss – these effects are all supported by laboratory and animal studies. Additionally, Castor Oil is traditionally used to promote circulation, for example through massages. Many users swear by this effect, but it has not been scientifically proven. Below, we will take a closer look at all known effects of Castor Oil.

Moisturizing effect of Castor Oil

Castor Oil forms a protective film on the skin and hair, preventing excessive moisture loss. This keeps the skin soft and nourished for longer.

Castor Oil is very viscous, meaning it has a high viscosity and therefore acts as an occlusive. This means it forms a protective film on the skin and hair, which reduces fluid loss through the skin. This keeps the skin hydrated for longer. This property is also described in dermatological reviews and pharmacological reference works, where castor oil is classified as an emollient, occlusive ingredient.¹ ²

Antibacterial & Antifungal Effect of Castor Oil

Castor Oil can inhibit bacteria and fungi – several studies have shown this. This is likely due to fatty acids contained in Castor Oil, which support the skin's defense system.

Due to its antimicrobial properties, sodium ricinoleate is a main component in certain dental solutions. It is a surface-active substance that presumably attacks the cell walls of bacteria and fungi, causing the microbes to die. How this mechanism works exactly is still unclear.³

Clinical studies have also shown that a 2% castor oil solution is as effective as an alkaline peroxide solution in removing biofilm on dentures. And not only that: it is also significantly more effective than saline solution.⁴

In another study, a 10% Ricinus communis solution had a similar effect to a 0.25% sodium hypochlorite solution in people with inflamed gums under dentures. The inflammation healed in about half of the study participants.⁵

And: Several reviews indicate that fatty acids like ricinoleic acid can destabilize bacterial cell walls and support innate immune defense. This also makes the antimicrobial effect of castor oil solutions plausible.⁶

Anti-inflammatory effect of Castor Oil

Studies in animals show that ricinoleic acid has anti-inflammatory effects. It dampens certain nerve messengers, thereby reducing swelling and pain.

In one study, scientists treated inflammation on the paws of rats with ricinoleic acid for several days. They found that the inflammation was significantly less pronounced than in the control group. In addition, the tissue contained significantly less Substance P – a messenger that amplifies pain and inflammatory reactions.⁷

A second study used the same animal model, but focused more on the role of messengers and nerve cells. Here, too, swelling could be reduced with ricinoleic acid, but above all, tissue samples showed a strong reduction of two inflammatory messengers (Substance P and Neurokinin A). As part of this study, in-vitro experiments were also carried out on nerve cells. The finding: Ricinoleic acid significantly reduced the transmission of pain signals, for example due to stimuli such as sharpness (capsaicin) or acid. Presumably, because the substance calms the nerve cells and thereby alleviates inflammation and pain.⁸

Circulation-promoting effect of Castor Oil

In natural cosmetics, Castor Oil is traditionally used in conjunction with gentle massages. The aim is to promote microcirculation. While many users report positive effects, scientific proof of this effect is still pending.

Castor Oil: Effects on Skin Care & Wound Healing

Animal studies have shown that castor oil can promote wound healing and have antimicrobial effects. In skincare, it is traditionally used to support skin regeneration, strengthen the skin barrier without clogging pores, and make the skin more supple.

Castor oil can support wound healing – researchers have demonstrated this in one of the mentioned animal models. According to this, ointments with castor oil ensure that wounds contract faster (wound contraction) and are covered with new skin cells more quickly (epithelialization). They also increase collagen production.⁹

Castor oil-containing polymer hybrids (wound dressings) have shown a similar effect in animal experiments: improved re-epithelialization and tissue regeneration.¹⁰ In addition, according to various laboratory studies, castor oil also appears to have antibacterial activity against certain skin germs.¹¹ This is further evidence that castor oil is excellently suited for skin care.

In natural cosmetics, castor oil is traditionally used to promote skin regeneration, improve its elasticity, and reduce the appearance of scars or stretch marks. However, these effects have not yet been scientifically proven – they are based on numerous reports from many users.

On the other hand, the low comedogenicity (~1) of castor oil has been proven.¹¹ It strengthens the skin barrier without clogging pores and is therefore often recommended for the care of blemished skin.

Castor Oil: Effects on Hair & Scalp Care

Castor oil is often used as a scalp treatment or overnight mask because it adds shine and makes hair more supple. Animal models also suggest that castor oil promotes hair growth. However, this effect has not yet been scientifically proven in humans.

A preclinical study has shown that castor oil-containing formulations led to both an increase in hair density and accelerated hair regrowth in rabbits, for example.¹²

Although comparable studies on hair growth in humans are not yet available, castor oil is very popular in natural cosmetics for this purpose, among others. Users are advised to massage the oil into the scalp, as this is said to vitalize the hair roots and stimulate growth. The aforementioned overnight treatments are also very common. The desired effect, shine and suppleness, is also plausible given the occlusive and nourishing properties of the oil.

Castor Oil: Effects on Eyelashes & Eyebrows

Thanks to its nourishing properties, castor oil can moisturize eyelashes or eyebrows, making them appear more supple, shinier, and optically stronger. However, scientific evidence for increased eyebrow or eyelash growth in humans is still lacking.

In a randomized, placebo-controlled study, participants had pure castor oil applied to their upper eyelashes daily for 6 weeks. The placebo group received an identically looking oil without active ingredients. After the study, some participants subjectively reported that their eyelashes looked more nourished, but no growth effect compared to the control group could be detected.¹³ At this point, another study with a longer observation period would be useful – after all, the growth cycle of eyelashes (4-11 months) significantly exceeds the study period.

Regardless of potential effects on hair growth, castor oil is characterized by high viscosity and its occlusive properties. Thus, the oil can coat the fine hairs, retain moisture, and thereby make them appear more supple and shinier – a cosmetic effect that is plausible and well-documented in skincare.¹⁴

In natural cosmetics, castor oil is used as a natural alternative to chemical eyelash serums, regardless of any study results. Regular application reportedly makes eyelashes and eyebrows appear stronger and denser, according to user reports.

Castor Oil: Effects on Lips & Nails

Castor oil forms a protective film on the lips, preventing them from drying out and making them more supple. Traditionally, castor oil is also used to make lips softer and nails appear stronger – however, this is based on anecdotal evidence.

A review article concludes that castor oil is an occlusive (film-forming) oil that reduces transepidermal (through the skin) water loss. In addition, the authors classify castor oil as an emollient, i.e., a nourishing ingredient that smooths the skin, makes it more supple, and leaves a pleasant skin feel. Accordingly, castor oil can protect chapped lips or dry cuticles from further dehydration and make the skin more supple.¹⁵ ¹⁶

Traditionally, castor oil is used as a conditioning agent for softer lips and stronger nails. Many users therefore appreciate it as a natural ingredient in lip balms or as nail oil, even if these effects are based on experience and have not yet been scientifically proven.

Castor Oil: Effects on Beards

There is much to suggest that castor oil softens the beard and protects the skin underneath from dryness, even though studies explicitly dealing with beard care with castor oil are still pending.

Here again, the already repeatedly described and scientifically proven properties of castor oil come into play:

• Occlusive oil
• Reduces water loss through the skin
• Emollient¹⁷ ¹⁸

It is more than plausible that, given these properties, castor oil can also have positive effects in beard care, such as a reduction in dryness and irritation of the skin under the beard.

Preclinical studies also demonstrate the antimicrobial properties of ricinoleic acid, the main component of castor oil, according to which it inhibits the growth of certain bacteria and fungi.¹⁹ This property should also have a beneficial effect on the skin under the beard.

Traditionally, users of castor oil for hair care expect more shine and suppleness, which is quite likely given the high viscosity of the oil. This also applies to beard care.

How do Castor Oil Packs work?

Castor oil packs are cloths soaked in castor oil, traditionally placed on the abdomen for detoxification. This detoxifying effect has not yet been scientifically proven.

Castor oil packs have been used in naturopathy for decades. They are placed on the abdomen or liver region, often in combination with a hot water bottle. Users report a warming, soothing, and relaxing effect, some also an detoxifying effect. However, according to a review article, there is currently no scientific evidence for this effect. Instead, the author attributes the perceived benefits of castor oil packs more to the application of heat and the associated soothing, relaxing effect than to a pharmacological effect of the oil itself.²⁰

Castor Oil: The Effects of the Pechoti Method (Pechoti Drop)

In the so-called Pechoti method, also known as Pechoti Drop, castor oil is dripped into the navel to achieve positive effects on digestion, hormones, and general well-being. While many users swear by this effect, it has not yet been scientifically proven.

Ayurvedic teachings consider the navel to be the energetic center of the body. The navel is said to house the so-called Pechoti gland, which serves to absorb substances and distribute them throughout the body. In practice, this substance is often castor oil, as it is believed to have a regulating effect on digestion, hormones, and general well-being. However, according to current medical knowledge, there is no verifiable "Pechoti gland," and there are no clinical studies confirming an internal effect of oil in the navel.²¹ ²²

The fact that many users of the Pechoti method report noticeable benefits is attributed by scientists to general factors, such as the moment of calm, self-care during the ritual, or the placebo effect.

How does Castor Oil affect digestion?

Castor oil strongly stimulates bowel activity and usually takes effect within a few hours. During pregnancy, castor oil should only be used in this context under medical supervision.

Castor oil has a strong laxative effect when taken orally: In the intestines, special enzymes (lipases) break down the oil into its active component, ricinoleic acid. This binds to specific control points of the intestinal muscles (so-called EP3 receptors) and thus stimulates bowel movement. The effect usually sets in after 1 to 3 hours. However, castor oil can also cause side effects such as abdominal cramps, diarrhea, nausea, and electrolyte disturbances. During pregnancy, a medical assessment is advisable here, as ricinoleic acid can occasionally trigger uterine contractions.²³ ²⁴

References

¹ Lin T-K, Zhong L, Santiago JL. Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils. Int J Mol Sci. 2017;18(11):244. doi:10.3390/ijms18112444. (Review: Plant oils, including Castor Oil, have occlusive effects, reduce TEWL, and support the skin barrier) PMC5796020

² Draelos ZD. Cosmetic Dermatology: Products and Procedures. 2nd ed. Wiley-Blackwell; 2015. (Castor Oil classified as an “occlusive emollient” in skincare)

³ Salles MM et al. Antimicrobial activity of complete denture cleanser solutions: A literature review. J Appl Oral Sci. 2015. (Mechanism/Detergent, cell wall damage).

⁴ Andrade IM et al. Trial of an experimental castor oil solution for cleaning dentures. Braz Dent J. 2014. (RCT on biofilm removal).

⁵ Badaró MM et al. Clinical trial for evaluation of Ricinus communis and sodium hypochlorite solutions… J Appl Oral Sci. 2017. (clinical findings in denture stomatitis).

⁶ Guimarães A et al. The Potential of Fatty Acids and Their Derivatives as Antifungal Agents. Front Microbiol. 2022; and Fischer CL et al. Antimicrobial Activity of Host-Derived Lipids. Microorganisms. 2020. (antimicrobial activity of unsaturated fatty acids in general).

⁷ Vieira C. et al. Effect of ricinoleic acid in acute and subchronic experimental models of inflammation. Mediators of Inflammation. 2000;9(5):223–228. Finding: Inhibition of carrageenan-induced edema after 8 days of RA application; reduction of Substance P in tissue. (PMCID: PMC1781768).

⁸ Vieira C. et al. Pro- and anti-inflammatory actions of ricinoleic acid: similarities and differences with capsaicin. Naunyn-Schmiedeberg’s Arch Pharmacol. 2001;364(2):87–95. Finding: Anti-edema effect after repeated administration; −75–80% Substance P, −46–51% Neurokinin A; RA inhibits capsaicin-/pH-induced currents in DRG neurons and reduces CGRP release (24 h).

⁹ Soujanya K. et al. Wound healing activity of polyherbal formulation with castor oil base in rats. Indian J Pharm Sci. 2020;82(2):309–315.

¹⁰ Muzammil KM et al. Castor oil-based polyurethane hybrid biomaterials promote wound healing in vivo. J Biomed Mater Res B Appl Biomater. 2021;109(2):205–214.

¹¹ Lin T-K, Zhong L, Santiago JL. Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils. Int J Mol Sci. 2017;18(11):244.

¹² Ali N. et al. Evaluation of hair growth potential of herbal hair oil in albino rabbits. Int J Pharm Sci Res. 2012;3(1):546–550. (Castor oil in combination with other plant oils accelerated hair growth in rabbits.)

¹³ Kumar N. et al. A randomized, double-blind, placebo-controlled trial of castor oil for eyelash growth. J Cosmet Dermatol. 2016;15(4):e22–e28. (No significant effect on eyelash growth compared to placebo.)

¹⁴ Lin T-K, Zhong L, Santiago JL. Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils. Int J Mol Sci. 2017;18(11):244. (Castor Oil described as an occlusive, moisturizing plant oil.)

¹⁵ Lin T-K, Zhong L, Santiago JL. Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils. Int J Mol Sci. 2017;18(11):244. (Castor Oil as an occlusive, moisturizing oil that reduces TEWL and supports the skin barrier.)

¹⁶ Draelos ZD. Cosmetic Dermatology: Products and Procedures. 2nd ed. Wiley-Blackwell; 2015. (Castor Oil described as an occlusive emollient in cosmetics, frequently used in lip and skin care products.)

¹⁷ Lin T-K, Zhong L, Santiago JL. Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils. Int J Mol Sci. 2017;18(11):244. (Castor Oil as an occlusive oil that reduces TEWL and supports the skin barrier).

¹⁸ Draelos ZD. Cosmetic Dermatology: Products and Procedures. 2nd ed. Wiley-Blackwell; 2015. (Castor Oil described as an “occlusive emollient,” used in cosmetics for hair and skin care).

¹⁹ Andrade IM et al. Trial of an experimental castor oil solution for cleaning dentures. Braz Dent J. 2014;25(1):43–47. (Antimicrobial activity of Ricinus communis solution, inhibitory against biofilm and microbes in the oral context).

²⁰ Bosland MC. Castor oil: fact and fiction. J Altern Complement Med. 2005;11(5):939–943. (Review article: Castor Oil Packs have been used in naturopathy for decades, scientific evidence for "detox" effects is lacking.)

²¹ Healthline. Pechoti Method: What You Need to Know. Healthline Media; 2024. (Review article: Traditional application of the Pechoti method described; no evidence for a physiological "Pechoti gland" or demonstrable internal effect.) Available at: https://www.healthline.com/health/pechoti

²² Health.com. Does Putting Castor Oil in Your Belly Button Have Benefits? Health; 2024. (Review article: Castor Oil in the belly button is used in the wellness area; experts emphasize the lack of scientific evidence, benefits are more likely explained by warmth and relaxation.) Available at: https://www.health.com/castor-oil-in-belly-button-11697683

²³ Tunaru S. et al. Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors. PNAS. 2012;109(23):9179–9184.

²⁴ StatPearls. Castor Oil. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; Updated 2024.