Castor Oil and Curly Hair

Castor Oil and Curly Hair

Castor oil has been a staple for many individuals in their personal hair care journey. Its popularity has been on the rise recently as more curlies learn how this plant derived oil can benefit their hair care routines.

Castor oil is a vegetable oil that is derived from the castor bean typically through a press. The produced oil is a pale yellow color featuring a very distinct odor and taste. The oil is mostly comprised of ricinoleic acid that is beneficial due to its chemical composition.

Since the castor beans derived oil contains the unique compound ricinoleic acid, the oil is a bit more polar than most other oils. This increased reactivity allows for chemical derivatization that isn’t really seen with other seed oils meaning more essential compounds are contained in the extracted thick oil.  Because of this ability castor oil is very useful in a multitude of industries but for hair and skin, castor oil is desired for its moisturizing and conditioning of the skin and hair. Many producers utilize this ingredient in products intended for increasing moisture, or to address skin irritations on the scalp caused by extended periods of dryness. 

When considering purchasing castor oil many encounter a multitude of brands and processing methods. The castor bean contains a known toxic enzyme called ricin. The heat generated during processing safely neutralizes this compound.  Some processes utilized heat directly to denature the enzyme so that the oil is safe for use prior to processing. In this heating process, the bean is roasted and the pressed oil is much darker and more full of essential nutrients extracted from the cell walls of the bean and infused into the oil. This particular method has been perfected for generations in Carribean cultures like Jamaica. Jamaican black castor oil (JBCO) has become highly sought after due to its ability to aid in the treatment of dandruff, acne, its growth promotion, and even its abilities to ease muscle pain. 

If moisture and healthy hair growth is your goal, then either JBCO or pure castor oil will work. But remember, there is no scientific proof that JBCO or any type of castor oil will make your hair follicles thicker or grow faster, but the anti-inflammatory fatty acids found in the oil encourage blood circulation, which helps to create a healthy scalp and promote more hair growth. Applying either castor oil is great for thinning spots in the hair and even growing your eyebrows or eyelashes.

Traditional seed oils are produced through cold presses. Where immense amounts of pressure are applied to the beans and the desired oil is extracted. Usually, this oil is very light in color. The immense amounts of pressure actually generate heat which is enough to neutralize the toxic enzyme ricin. Included in the pressed oil are other nutrients and additional essential fatty acids found within the castor bean. Additionally, this process is less alkaline than the roasting process which could prevent any irritations if the scalp is itchy or dry.  Some producers will use solvents to make the extraction process cheaper and quicker but many of the key nutrients be extracted in a cold press. with all seed extractions, cold extractions are the best choice for use in medicinal, food, or cosmetic products. 

The term moisturizer is very broad and in this instance, castor oil is considered an emollient which is a moisturizer that causes the hair shaft to be encapsulated. Unlike some moisturizing emollient ingredients, castor oil doesn’t leave the greasiness associated with other sealing oils like shea butter. Because castor oil can reduce product build-up on the scalp there is a known reduction in the chance for skin irritations making castor oil an extremely helpful ingredient for those suffering from irritations of the scalp. 

Curly, coily and kinky hair typically see the most benefit from castor oil due to the inherent dryness of curlier hair textures. The textures of hair are related to the shape of the cuticle as it exits the follicle. Straight hair is circular and symmetrical versus coily hair which is a flat oval shape.  Hair shafts that have more raised cuticles are considered to be more porous and harder to restrict the movement of moisture and nutrients out of the hair shaft. Sealing oils like castor oil are great for highly porous hair because it can seal the hair shaft trapping needed moisture and nutrients for balancing hair health and moisture. 

All of the hair types react differently to thick oils like castor oil making it essential to have a good understanding of hair texture and the cyclic moisture needs of the hair shafts.  Some people with finer and less porous hair may find castor oil too thick for the hair leaving it greasy and in need of cleansing. Mixing castor oil with another lighter oil will make it much easier to determine the exact needs of the hair. Straight hair would only use castor oil for repair and for cleaning the scalp whereas a coiled texture would use the oil for sealing in moisture on a frequent basis. Castor oil can be substituted into the “curly girl method” 

For example, castor oil can be mixed with lighter carrier oils such as coconut oil, black seed oil, jojoba oil, olive oil or grapeseed oil. Other identified helpful ingredients like essential oils can be combined with the castor oil/carrier oil blend to add more functionality to haircare products. Common oils used are rosemary, lavender, thyme, cedarwood or chamomile.

Castor oil solutions should only be applied 1-2 times per week. Apply to damp, pre sectioned curls, working it from scalp to ends. Make sure to massage it into the scalp to get the antibacterial and scalp stimulating benefits.  This mixture works best when applied as an overnight hair treatment, which can then be washed when hair becomes overwhelmed with grease using a gentle cleansing shampoo.  Many products on the market blend castor oil with other components to achieve a functional moisturizing product.

ROBBINS, CLARENCE R. Chemical and Physical Behavior of Human Hair. 5th ed., SPRINGER, 2016.
Leidamarie, Leidamarie. “Helix Magazine.” The Science of Curls | Helix Magazine, 20 May 2014,
“Castor Oil.” Wikipedia, Wikimedia Foundation, 6 May 2019,