What's the Deal with Castile Soap?

There's no shortage of uses for this do-it-all cleanser.

dr. bronner's pure castile soap against a terrazzo background
Photo: Dr. Bronner's/Tony Stock/Shutterstock

Breaking news: Not all soap is created equal. And that's why pure castile soap — made from plant-based oils — has been lauded for years as being gentler and more versatile than any other soap out there. So what's the deal with castile soap? Ahead, everything you need to know about this multi-tasking sudser, exactly how to use castile soap, and the best castile soap brands to try.

Castile Soap vs. Other Soaps

Originally named after the olive oil–based soaps from Castile, Spain, castile soaps these days are made from olive oil and a variety of other oils, all of which are plant-, nut-, or vegetable-derived. Coconut, hemp, almond, and walnut oil are all commonly used, and castile soap can come in either liquid or solid form.

Along with these oils, castile soaps contain lye, which, creates soap molecules when mixed with the oil. Mix that soap with water and it creates charged atoms that capture dirt and other grime.

So, how does castile soap differ from any other kind of soap? It all goes back to those oils. Traditional soap uses tallow (aka animal fat), making castile soap a vegan, cruelty-free alternative. (Being vegan isn't just about changing what you eat. Besides reexamining bath products, here are 12 things no one tells you about going vegan.)

Other soaps and cleaning products may also contain harsh detergents; pure castile soap is totally natural, non-toxic, and biodegradable. And that's exactly why it can be used as both a beauty product and household cleaner, as it can effectively clean everything from your face to your faucets. It's also super affordable, so replacing multiple different products with this one all-purpose solution can be a great way to not only save space but some of your hard-earned cash too.

The Best Uses for Castile Soap

Truly, there's not much it can't do. Case in point? The OG — Dr. Bronner's Castile Soap, which you've likely seen on Instagram — touts 18 different uses. Heads up: Pure castile soap is concentrated and needs to be diluted with water, but the exact soap-to-water ratio differs depending on the intended use.

When it comes to beauty and personal care purposes — using it as a face wash, body wash, shampoo, or shaving cream — the water that gets naturally mixed in during the process will be enough to dilute it. Plus, since it's non-toxic, your whole family can use it — and it even works as a great dog shampoo. (You can also use castile soap to clean your makeup brushes.)

For household use, check out all these different things it can do, along with some general dilution guidelines. (Find these and even more ratios using this Dr. Bronner's dilution cheat sheet.)

  • For a multi-surface cleaner, mix 1/4 cup castile soap with 1 quart water.
  • For a dish detergent, use 1 part castile soap to 10 parts water.
  • For a floor cleaner, mix 1/2 cup castile soap with 3 gallons water.
  • For a fruit and veggie wash, add a dash castile soap to a bowl of water.
  • For a laundry detergent, add 1/3 to 1/2 cup castile soap per load, and add 1/2 cup vinegar to the rinse cycle (more on why in a minute).
  • For an insect-repellent for plants, mix 1 tablespoon soap with 1 quart water.

So, is there anything you shouldn't use castile soap for, or any instances where it should be avoided? Again, as long as you're diluting it properly, not really, but there are a few caveats. For one, it's not a great option for color-treated hair, as it can strip out the dye molecules.

Also, you don't want to combine acids (such as vinegar or lemon juice) with castile soap. Castile soap is alkaline, so the two will essentially counteract one another and can result in a leftover film or residue on whatever you're trying to clean. Still, castile soap can sometimes leave salt deposits behind, so those acids can come in handy afterward. For example, try using an apple cider vinegar rinse on your hair after shampooing with castile soap, or dip castile soap–washed dishes in a vinegar-and-water solution.

The Best Castile Soap Brands

Dr. Bronner's Pure Castile Soap in Peppermint (Buy It, $12, target.com)

Arguably the brand that put castile soap on the map in the U.S., Dr. Bronner's offers a total of seven scents as well as an unscented baby version, plus solid bars too. Also nice: It's made with fair-trade and organic ingredients, and housed in a recyclable bottle.

Follain Refillable Everything Soap (Buy It, $18, follain.com)

Made with coconut, olive, and jojoba oils, take your pick from a lavender or lemongrass scent. Purchase the chic bottle once and the refills separately thereafter, minimizing your impact on the environment.

Real Castile Bar Soap (Buy It, $11, amazon.com)

Solid soap fans will appreciate this bar, ideal for stashing in the shower. Like the original castile soaps, it uses only extra-virgin olive oil.

Cove Castile Soap Unscented (Buy It, $18, amazon.com)

Purists will appreciate this simple and scent-free choice, and bulk shoppers will appreciate that it's also available in an extra-large, gallon-size pump bottle.

Quinn's Pure Castile Organic Liquid Soap (Buy It, $14, amazon.com)

With vintage-inspired packaging, this bottle of castile soap will look especially pretty perched on your bathroom counter or in the shower.

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