Castor beans are cultivated for the oil extracted from the seeds; it is produced by cold pressing the seeds followed by clarification of the oil by heat. . The castor bean from which oil is extracted contains toxic and allergenic chemicals, but these are not present in the oil itself, because ricin does not partition into the oil. The toxicity of the seeds makes them harder to cultivate and process.
Castor oil has better low-temperature viscosity properties and high-temperature lubrication than most vegetable oils, making it useful as a lubricant for engines. It’s also a great material for use as a raw material in chemical synthesis: the chemical reactivity of the alcohol group also allows chemical derivatization that is not possible with most other seed oils
How about skincare?
Castor oil is not magic (almost nothing is). If you like its high viscosity, you could replace it with rice bran oil, for example.
Is there anything special about its fatty acid composition? Ricinoleic acid may have some analgesic and anti-inflammatory effects. Castor oil is well known as a source of ricinoleic acid, a monounsaturated, 18-carbon fatty acid. Among fatty acids, ricinoleic acid is unusual because it has a hydroxyl functional group on the 12th carbon atom; this functional group causes ricinoleic acid (and castor oil) to be more polar than most fats. This may help a bit when used as an ingredient in an oily cleanser.
Why use an oil-based cleanser?
To clean your skin, you could just use just water, but in this case, much of the “grime” of the day will stay put.
You could use some soap and water, but you may remove stuff that needs not be removed, like fatty acids and ceramides that are part of your skin barrier, which prevent the outside pollutants from getting in and keep water inside.
There are not many ways to cleanse your skin while protecting its integrity. You need to preserve the skin barrier, avoid irritation and dryness and still remove the “gunk”, which includes excess dust, pollutants, and whatever else settled on the skin during the day, plus remove excess sebum, and dead cells, etc.