Castor oil is pressed from the seeds of the castor plant and is chemically distinctive because it is roughly 85 to 90 percent ricinoleic acid, a hydroxylated fatty acid rarely found at this concentration elsewhere in nature. That hydroxyl group gives castor oil a higher viscosity and more film forming, slightly tacky feel than most plant oils.
Isolated ricinoleic acid has shown genuine anti inflammatory activity in animal models, reducing swelling through a receptor pathway distinct from the one targeted by common anti inflammatory medications. On skin, castor oil's thick film also lends itself to eyelash and eyebrow serums, though the popular claim that it grows longer lashes or thicker hair is not well supported by controlled human trials, and the fuller look it produces may come largely from its shine and coating effect rather than genuine new growth.
Castor Oil References
Effect of ricinoleic acid in acute and subchronic experimental models of inflammation, Mediators of Inflammation, 2000
Castor Oil, Properties, Uses, and Optimization of Processing Parameters in Commercial Production, Lipid Insights, 2016
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Reliable, well tolerated ingredients that do their job without complaint. They may not carry the headline benefits of a Best rated active, but they hydrate, stabilize a formula, or support the ingredients around them in ways that make a real difference in how a product performs and feels.
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Ingredients that are perfectly safe and serve a clear function, typically as an emollient, thickener, or filler, but do not offer any meaningful skin benefit beyond that basic job. Not a red flag, just not a reason to choose one product over another.
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Ingredients with documented potential to irritate skin, disrupt the barrier, or trigger sensitization in some users, often synthetic fragrance, drying forms of alcohol, or certain essential oils. Not automatically a dealbreaker for every skin type, but worth knowing about before you commit to a product.
