Ricinus Communis Seed Oil

This ingredient is also known as castor oil. It is a skin conditioning ingredient.

The star component of castor oil is ricinoleic acid, an unusual fatty acid that makes up ~80-92% of its composition.

In skincare, it is an emollient that dries down to a solid film with water-binding properties. This helps keep skin hydrated and helps reduce transepidermal water loss (TEWL).

A 2026 dermatology review pulls together its broader uses:

• A small single-arm trial found castor oil cream reduced under-eye melanin and redness over 2 months
• It's a safe carrier oil in phenol peels for melasma
• It has some antioxidant activity

Human clinical testing found this ingredient to be non-irritating and non-sensitizing.

Because castor oil contains fatty acids in the C11-24 range, this ingredient may not be fungal acne safe.

Hair growth

At this time, the literature does not support castor oil in regrowing hair. A 2022 systematic review found no strong evidence that it supports hair growth and only weak evidence that it improves hair shine.

Masking and perfuming

Castor oil itself carries "perfuming" and "masking" function tags according to the official CosIng database. This is because of its mild odor and odor-dampening properties.