One ingredient. Cold-pressed castor oil — Ricinus communis seed oil and nothing else. No refining, no chemical treatment, no additives, no preservative. 500 ml, the size that makes sense once you start using it on hair rather than only on lashes and nails.
Why it behaves unlike any other plant oil
Castor oil is roughly 90% ricinoleic acid, a fatty acid found in almost nothing else. That single fact explains everything about it.
Ricinoleic acid carries a hydroxyl group along its chain, which lets the molecules hydrogen-bond to one another. The result is an oil that is strikingly thick, sticky and viscous — and one that stays where you put it rather than spreading out and soaking away. That is why it is the oil used on brows and lashes, where anything thinner migrates into the eye; and why it makes a genuinely occlusive hair mask.
It is also why it is hard work to wash out, and why some people find it too heavy used neat.
The two questions everyone asks
1. “Isn't the castor bean the ricin plant?” Yes — and the oil is safe. Ricin is a large, water-soluble protein. When the seeds are pressed, the ricin stays behind in the solid seed cake; it does not follow the oil out. Cold-pressed castor oil contains no ricin, and it has been used as a cosmetic and a medicine for thousands of years. The plant is genuinely poisonous; the oil pressed from it is not.
2. “Can I take it internally?” Not casually. Castor oil is a stimulant laxative and a licensed medicine for that purpose — a powerful and fast one, which causes cramping and can cause dehydration and electrolyte loss. This bottle is sold as a cosmetic oil, not as a medicine.
And one absolute rule: never take castor oil internally during pregnancy. Ricinoleic acid acts on receptors in the gut that also stimulate the uterus — castor oil has been used for centuries to bring on labour, and that is precisely why it must not be swallowed by anyone pregnant. Using it on your hair or skin is a different matter and is fine.
How to use it
As a pre-wash hair and scalp mask — the main use for a 500 ml bottle. Warm two or three tablespoons between your hands, work it into the scalp and through the lengths, and leave it for an hour or overnight under a towel or a cap. Then shampoo twice. This is not optional: castor oil is heavy and a single wash rarely shifts it, which is the commonest reason people conclude it “left my hair greasy”.
If it feels too thick to spread, cut it half and half with a lighter oil — jojoba, sweet almond or coconut. Most people find the blend far more usable than neat castor oil, and it makes the bottle last twice as long.
Brows and lashes: a trace on a clean spoolie or brush at night, on the lash line rather than in the eye. Use very little. Do not get it into the eye itself — it stings, it blurs vision, and heavy oil around the lid margin can block the small glands there. Take it off in the morning. If your eyes become red or irritated, stop.
Nails and cuticles: a drop massaged into the cuticle nightly.
Beard: a few drops warmed and worked through, best left overnight and washed out.
Dry patches — heels, elbows, knees — where its occlusiveness is exactly the point.
What may not be claimed
Castor oil is surrounded by claims about hair growth, and we will not repeat them. There is no authorised health claim, and no good clinical evidence that castor oil makes hair or lashes grow. What it demonstrably does is coat and lubricate the hair shaft, which reduces breakage and makes hair look thicker and shinier — and hair that breaks less does, over time, get longer. That is a real and useful effect, and it is not the same as stimulating growth.
Cautions
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Patch test on the inner forearm before the first use. Castor allergy exists.
- Not for use on broken or badly inflamed skin.
- Keep out of reach of children — swallowed, it is a strong laxative.
- It stains fabric. Use an old pillowcase or a towel.
Storage
Cool, dark and tightly closed. Castor oil is unusually stable and will keep for a couple of years, but heat and light shorten that. If it ever smells sharp or sour, it has oxidised.