Castor oil, an oil with healing properties?

Castor vegetable oil is a particularly favoured natural ingredient for its strengthening effect on nails, hair, eyelashes, and eyebrows. It is primarily composed ofricinoleic acid(from 83% to 88%), a fatty acid known for its bactericidal and antifungal properties. Therefore, it is also used to purify acne-prone skin.

In terms of its organoleptic properties, castor oil has a greasy, viscous feel. Despite this, it is low in comedogenicity (comedogenicity index=1), meaning it does not clog pores. On the contrary, it is recognised for its good tissue penetration despite its viscosity.

Following a lesion or injury to the dermis, the healing process often leaves a visible mark on the skin known as a scar. During healing, the scar tissue does not have the same hue as the tissue it replaces, leaving a mark that is either lighter or darker. Depending on the severity of the injury, its location, and age, the scar may fade over time or persist for several years.

There are various types of scars:

• Thehypertrophic scarsappear reddish and are the result of long-lasting inflammations;

• Theatrophic scarsappear in the form of craters and are often caused by acne spots;

• Sclerotic scars appear hard and lack flexibility, they occur after burns;

• Keloid scarsare dark red marks that extend beyond the initial lesion, appearing as a result of trauma (surgical scars, acne...).

Firstly, it is important to clarify that a scar cannot completely disappear with the application of castor oil or any other compound. Only laser treatment is effective in completely removing a scar (and even then, this depends on its severity).

Next, regarding the effects of castor oil on scars, very few scientific studies currently exist on this subject using human skin explants. A study on the healing properties of pure castor oil involves the reduction of a significant wound in an elderly horse. It has been demonstrated that castor oil has bactericidal, healing, repelling, and larvicidal properties. Regarding the application of castor oil on human skin, a retrospective study involving 36 patients who underwent a skin graft examined the effects of a combined ointment containing castor oil, Peru balsam, and trypsin. According to the researchers, this ointment may improve healing. However, it is difficult to determine which compound actually influenced the healing, or if the result is due to a synergy between the three ingredients.

Thus,castor oil could potentially be relevant for topical application during the healing of a minor wound. Indeed, ricinoleic acid, a mono-unsaturated fatty acid present at about 85%, will combat bacterial colonisation and therefore prevent a minor lesion from becoming a significant scar.

How to use it? Daily, morning and evening, apply it to the targeted area and perform massages to enhance its absorption.

• NARAYANAN S. & al. Comparison of pressure ulcer treatments in long-term care facilities: clinical outcomes and impact on cost. Journal of Wound, Ostomy and Continence Nursing (2005).

• PERES A. R. & al. Use of castor oil in tissue repair of extensive wound in senile horse Medicine (2015).