What kind of castor oil is best?


Castor oil was one of the first cultivated crops, and has long been prized for its medicinal, beautifying, and chemical properties.

The best type of castor oil undoubtedly depends on the intended application. In this article, we’ll review the different types of castor oil, and when you might use them.

What is castor oil?

Castor oil is extracted from the beans of the castor plant, Ricinus Communis. Multiple farming, extraction, and processing methods are possible to obtain the castor oil.

Castor oil is rich in an important compound called ricinoleic acid, an unsaturated fatty acid. Ricinoleic acid comprises up to 90% of castor oil, and is believed to be responsible for several of the therapeutic benefits. The remaining proportion of castor oil is comprised of other unsaturated fatty acids and their glycosidic derivatives, which may also contribute to the pharmacological activity.

What is castor oil used for?

Castor oil has multiple applications, both traditional and modern. These include:

  • Anti-inflammatory agent for arthritis
  • Castor-oil packs
  • Topical treatment of skin conditions
  • Hair growth topical
  • Digestive disorders
  • Menstrual or reproductive disorders
  • Inducing labor
  • Manufacture of soaps and lubricants
  • Biopolymer manufacture
  • Fuel and biodiesel

Factors that affect the type of castor oil

The quality of castor oil is affected by the quality of the castor beans. Just like any plant, growing conditions can have a substantial influence on the quality of the fruit. The castor plant is native to Africa and India, but is now grown worldwide to meet increasing demand for castor oil. However, the castor plant fares best in its native tropical climate.

Steps that are further down the processing chain also contribute to the final type and quality of the castor oil. For example, the extraction method may involve chemical extraction, manual pressing, or a combination of the two.

The temperature of pressed castor beans will affect the final chemical composition. A heated extraction may speed up the process and increase efficiency, but it will also result in chemical degradation and loss of certain bioactive molecules.

Finally, seeds may or may not be roasted prior to extraction. Roasted seeds yield black castor oil, as opposed to the yellow castor oil we are used to seeing. The roasting process changes the chemical composition of the seeds, so that the final product has distinctly different properties.

Here is a summary of the factors that influence the type of castor oil:

  • Growing conditions
  • Extraction method – chemical extraction or pressing
  • Temperature of processing (cold-pressed vs. regular)
  • Whether or not the seeds were roasted (yellow vs black castor oil)

Types of castor oil

The following are some of the labels you may see on castor oil. Note that these are not necessarily mutually exclusive, so there may be some overlap.

USP grade castor oil

USP grade castor oil is among the highest quality, since it must fulfill the criteria set by the United State Pharmacopeia. This type of castor oil is suitable for use in pharmaceuticals owing to its high purity.

Lab grade castor oil

Lab grade castor oil does not have to fulfill any specific purity standards, and is therefore appropriate for general use but not for human consumption.

Cold-pressed castor oil

Cold-pressed castor oil is kept at a low temperature during the mechanical extraction process. Keeping the temperature cool prevents the degradation of valuable compounds, thereby preserving the aroma, chemical properties, and pharmacological activity of the oil. This type of oil is great for medicinal and personal care applications.

Expeller-pressed castor oil

Expeller pressing is a mechanical extraction process. However, because the beans are not intentionally kept cool, the friction of the mechanical process is enough to contribute to some degree of chemical degradation. This type of castor oil is ideal for soaps, waxes, and lubricants.

First-press castor oil

As with extra virgin olive oil, first press castor oil will be (in many respects) superior quality. The first press contains fewer impurities from the beans or other residues, resulting in a thin, pale, low-acidity oil with relatively neutral aroma. This type of castor oil may be preferred for medicinal and personal care products.

Chemically-extracted castor oil

The oil that is left behind in the seeds following mechanical pressing can be extracted using a chemical solvent. This increases the oil yield from any given crop of castor beans. The residues left behind may make this castor oil unsuitable for personal care or medicine. This type of oil is probably best for industrial use.

Black Castor Oil (aka Jamaican Black castor oil)

Black castor oil is made from castor seeds that were roasted prior to extraction. Like most things, the roasting process results in a darker color and toasty aromas, which carries over into the final product. It has a distinct chemical composition, since important chemicals will have been transformed during the roasting process. This type of oil is often marketed for hair treatment and other health and beauty aids.

Which castor oil is best?

The best castor oil for you depends on your application. Lab Alley is pleased to provide you with USP grade castor oil for pharmaceutical or therapeutic uses. We also offer Lab Grade castor oil if your purity requirements are less strict, as in regular industrial use.

If you have additional questions about castor oil, or any of our products, please don’t hesitate to contact us.

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