The less than gentle things most of us do to make our hair look great may seem effective at first—but they often lead to just the opposite results in the long run. Whether it’s frequent blow drying, flat-ironing, perming, coloring, relaxing, or other harsh chemical products and treatments, years (or even decades) of washing and styling with heat and chemicals leaves hair looking dry, dull, brittle, frizzy, lifeless—and in need of a major intervention.

If you’ve been hanging your hopes on the latest expensive gadgets and formulas to rejuvenate your tresses, it’s time to break the cycle of short-term results that actually damage hair over time. It turns out that one of the safest and best ways to reveal truly healthy, glamorous locks is one of the most humble—it’s that bottle of natural castor oil that your grandmother (and probably her grandmother!) kept in the medicine cabinet all along.

What makes castor oil so special is its high concentration of ricinoleic acid, antioxidants, fatty acids, protein, vitamins, and minerals—which work together to nourish your hair and scalp and give your hair a full, glossy, smooth appearance that’s easy to manage no matter how you style it. If you’re ready for better hair than you ever thought possible, here’s how to create a luxurious deep conditioning castor oil treatment.

How to Condition with Castor Oil

Nothing could be easier than fixing up a castor oil hair conditioner because you only need one ingredient: castor oil! Just be sure to go with a single-ingredient product like Valentia that’s ethically sourced, cruelty-free, and doesn’t contain any added fragrance, preservatives, sulfates, parabens, or other harmful artificial additives. To deep condition your hair:

1. Spritz on some water so hair is damp, not wet. This makes it easier to apply the castor oil. You may also want to light a candle and put on some soft music to create a relaxing spa environment.
2. Work about a teaspoon (about 3-4 pumps) of castor oil into hair and scalp for a few minutes to coat each hair shaft. If your hair is very long or thick, you can increase the amount to about a tablespoon as needed. You may want to part your hair on one side, massage in a drop or two, and then repeat—moving the part over a little bit each time. (If you find the texture of castor oil alone too sticky, it’s fine to mix in a silky, healthy botanical oil like jojoba or argan.)
3. Cover hair with a shower cap to protect bedding, clothing, and furniture.
4. Leave treatment in for at least a few hours, preferably overnight.
5. Repeat once or twice weekly as needed.

Washing the Treatment Out

The longer you wait to wash out this treatment, the more benefit you’ll enjoy—and it will be easier to wash out since more of the castor oil will have time to be absorbed into your hair and scalp. When you’re ready to clean up, gently wash your hair with a natural shampoo as usual. If you’re finding it challenging to remove the castor oil, massage in a bit of your regular conditioner or a whisked, raw egg—and then shampoo again.

Specialty Treatment Ideas

A single tablespoon of castor oil makes a wonderful deep conditioner all by itself—but including a few other natural carrier and essential oils can help tailor your treatment to your specific hair issues. Just add:

For long and lovely hair:
• 1-2 drops rosemary essential oil
• 1 tablespoon coconut oil

To max out moisture and gloss:
• 1-2 tablespoons argan oil

For luscious fullness:
• 1 tablespoon almond or jojoba oil
• 1 drop lavender essential oil
• 1 drop clary sage essential oil

Castor oil treatments are a bit messy, but the results are well worth a little stickiness. Meanwhile, feel free to experiment and tweak the recipes until you find the perfect ingredient ratios for your unique tresses. With time and patience, this very down-to-earth hair care approach will help you achieve the healthiest, most head-turning hair of your entire life.