Ricinus Communis (Castor) Seed Oil
A very thick oil rich in ricinoleic acid. Seals in moisture and adds shine; Jamaican black castor oil is the same oil made from roasted beans.
About Ricinus Communis (Castor) Seed Oil
Castor oil is pressed from the seeds of the castor plant. Almost 90% of its fatty acids are ricinoleic acid, an unusual fatty acid with an extra hydroxyl group. That chemistry makes castor oil far thicker and stickier than other plant oils, and slightly more attracted to water.
In hair care it is a heavy sealant. It coats strands, slows moisture loss, adds high shine and gives a little grip, which is why people use it to lay edges, seal ends and smooth twists. Jamaican black castor oil (JBCO) is castor oil made by roasting the beans and boiling the paste before collecting the oil; the ash gives it its dark color and smoky smell, but on the label it is still Ricinus Communis Seed Oil.
Castor oil is widely promoted for growing thicker edges, eyebrows and hair. There is no good clinical evidence that it makes hair grow faster or thicker. What it can do is reduce breakage by keeping hair lubricated, which helps you keep length — so retention may improve even if growth doesn't change.
Who tends to love it: people with thick, coarse or high porosity hair, and anyone sealing ends. Who may find it too heavy: fine or low porosity hair, where it can look greasy, attract lint and be hard to wash out. Mixing a few drops with a lighter oil helps. It is approved for the Curly Girl Method. Patch-test on the scalp if you have sensitive skin.
How our checker rates it
| Mode | Rating | Why |
|---|---|---|
| Curly Girl | OK | No concerns for this mode. |
| Relaxed hair | Good | Softens and helps seal in moisture. |
| Low porosity | Caution | Heavy ingredient near the top of the list — can sit on low-porosity hair and build up. |
| Protein-sensitive | OK | No concerns for this mode. |
Ratings assume it is listed near the top of the label. After the first preservative or fragrance (likely 1% or less) most cautions soften.
What oil ingredients do
Plant and synthetic oils that soften, add shine and slow moisture loss. Some (like coconut) can enter the hair shaft; most coat the surface.
This one is on the heavy side, so it can weigh down fine or low-porosity hair if it sits near the top of a product’s list.
Also listed as
- castor oil
- ricinus communis seed oil
- ricinus communis oil
- jamaican black castor oil
- black castor oil
- jbco
- haitian black castor oil
Similar ingredients
Sources
Last data update:
- Robbins CR. Chemical and Physical Behavior of Human Hair. 5th ed. Springer; 2012. Reference text on hair structure, surfactants, conditioning agents, protein, heat and chemical treatments.
- Cosmetic Ingredient Review (CIR). Ingredient safety assessments. Safety assessments for cosmetic ingredients cited on ingredient pages.
How we research and update pages: editorial policy. Spotted an error? Tell us.