Ricínio

The large bottle of Propos'Nature's organic castor oil — the same single-ingredient, cold-pressed oil as the 50 ml, in the size that makes sense once you use it on hair rather than only on lashes and nails.

Cold mechanical pressing, no refining, no chemical treatment: what comes out is Ricinus communis seed oil and nothing else. It is around 90% ricinoleic acid, which is what makes it so much thicker and stickier than other plant oils — and why it stays where it is put instead of soaking away.

• 500 ml — the hair-treatment size
• 100% organic virgin castor oil, cold pressed
• Single ingredient — no additives, no preservatives
• Seed origin: India · certified organic cosmetic
• Hair, scalp, beard, lashes, brows, nails

How to use. As a pre-wash hair mask: warm two or three tablespoons in the hands, work through the scalp and lengths, leave for an hour or overnight under a towel, then shampoo twice — it is heavy and one wash rarely shifts it. On brows and lashes, a trace on a clean brush at night. On nails, massage into the cuticle. If it feels too thick to spread, cut it half and half with a lighter oil such as jojoba or sweet almond.