Castor oil for hair: what it is, what it does, how we blend it
Castor oil is about twenty times thicker than jojoba: a rich, glossy, syrup-like active that grips the hair and stays where you put it, used at 8.4% in Full Measure.
| Role | Active oil |
|---|---|
| Weight | 4 of 4, rich |
| Chosen for | Strength, fuller look |
| On the label | Ricinus Communis (Castor) Seed Oil |
| In our blends | Full Measure 8.4% |
| Builder limit | Up to 10% of a hair blend |
What it is
Pressed from the seeds of Ricinus communis (the toxic protein ricin stays in the seed cake, not the oil), castor oil is about 90% ricinoleic acid, a fatty acid with an extra hydroxyl group that makes the molecules cling to each other. That is why it measures roughly 700 centipoise at room temperature against about 33 for jojoba, and why it thins so much when warmed: the number falls by more than half between 25 C and 37 C. It is pale, with a faint, slightly waxy scent.
How it feels on hair
Weight 4 of 4, rich. It pulls between the fingers, spreads slowly, and leaves a high-shine coat with real hold, which is the fuller look our library lists it for. Warm it between the palms and it spreads twice as far from the same drop.
Who reaches for it
Thick, coarse and coily hair, edges and ends that want a glossy hold, and anyone building a pre-wash oil. On fine hair it is a lot; the builder shows its weight class so you can judge.
Where it sits in our blends
Full Measure carries castor at 8.4% (with Fractionated Coconut 78.5%, Pumpkin Seed 6.3%, Black Seed 5.3%, and more). Open it in the builder, change any oil, name it and we weigh it for you.
How to compose with it
The builder allows castor up to 10% of a hair blend. Full Measure leads the actives with it at 8.4% beside pumpkin seed and black seed over fractionated coconut, which keeps the bottle pourable. Pair it with a thin base and set the actives' share low if you want slip rather than hold.
Good to know: Very thick. Over a rich base the bottle will pour slowly; the pump handles it, the dropper is slower.
Compose with castor Find your formula
Weighed to the gram and blended to order in New Jersey, with the recipe printed on the label. For external use only; patch test before first use. Every oil, with its INCI name, is in the oil library.