If you’re aiming for a cleaner, simpler, more natural lifestyle, your hair care routine is a great place to start. And one of the most versatile, non-toxic alternatives to conventional shampoo is liquid Castile soap.
Made from plant oils and completely biodegradable, Castile soap offers a natural way to cleanse your hair without synthetic detergents, sulfates, or mystery chemicals. But is it right for your hair type? How do you use it without drying your scalp? And what about the “transition” period?
Let’s dive into everything you need to know about using liquid Castile soap as shampoo—including benefits, how-tos, and tips for healthy, happy hair.
🧼 What Is Castile Soap?
Castile soap is a concentrated, oil-based soap originally made from olive oil in the Castile region of Spain. Today, it typically includes a blend of natural oils like:
- Olive oil
- Coconut oil
- Jojoba oil
- Hemp oil
It’s free from:
- Sulfates (SLS/SLES)
- Parabens
- Silicones
- Artificial fragrances
- Animal fats or byproducts
Castile soap is vegan, biodegradable, and multi-purpose, making it a staple in many natural homes.
Check out our absolute favorite Castile soap here!
💧 Why Use Castile Soap on Your Hair?
Traditional shampoos often contain harsh surfactants that strip your scalp of its natural oils, which can lead to overproduction of sebum, dry scalp, or irritation.
Castile soap offers a gentler, more holistic approach.
🌿 Benefits of Using Castile Soap for Hair:
- Non-toxic & chemical-free
- Gentle cleansing without over-drying
- Restores scalp balance and supports healthy hair growth
- Cost-effective and highly concentrated
- Eco-friendly & sustainable
It’s especially appealing if you’re dealing with:
- Sensitive skin or scalp
- Itchy or flaky scalp
- Hormonal hair issues
- A desire to eliminate plastic shampoo bottles
🧴 How to Use Castile Soap as Shampoo
Since Castile soap is very concentrated and alkaline, it’s best to dilute it before using it on your scalp.
✅ Basic Castile Soap Shampoo Recipe:
Ingredients:
- 1 tablespoon liquid Castile soap
- ½ cup distilled water or herbal tea (like chamomile or rosemary)
- Optional: 3–5 drops of essential oil (lavender, rosemary, peppermint)
Instructions:
- Mix all ingredients in a bottle.
- Shake gently before each use.
- Pour directly onto your scalp and massage in.
- Rinse thoroughly.
💡 For very dry hair or curly textures, add a teaspoon of aloe vera, glycerin, or a carrier oil (like jojoba) to your mix.
🧪 Important: Follow with an Acidic Rinse
Because Castile soap is alkaline, your hair cuticle may remain slightly open after washing, leading to tangles or a filmy feel. The fix? Use an acidic rinse to restore your scalp’s pH.
🍎 DIY Apple Cider Vinegar (ACV) Hair Rinse:
- 1 tablespoon raw apple cider vinegar
- 1 cup water
- Optional: A few drops of lavender or rosemary essential oil
How to Use:
- After washing with Castile soap, pour the ACV rinse through your hair.
- Let it sit for 1–2 minutes.
- Rinse thoroughly with cool water.
This helps smooth the hair cuticle, reduce frizz, and restore shine.
🧠 What to Expect: The Transition Period
If you’re switching from conventional shampoo to Castile soap, expect a transition period of 1–3 weeks while your scalp adjusts.
You might notice:
- Greasier roots (your scalp may be overproducing oil at first)
- Drier ends
- A waxy or sticky feeling
Don’t panic—this is normal. Stick with it, and your scalp will balance itself over time.
✨ Tip: Brushing your hair with a boar bristle brush can help redistribute natural oils from your scalp to your ends.
💇 Is Castile Soap Right for Your Hair Type?
✅ Great for:
- Normal to oily hair
- Short hair
- Fine hair
- People looking to detox from commercial shampoos
⚠️ Use with caution if:
- You have very dry or color-treated hair
- You’re prone to product buildup
- You have hard water (it can react with soap and leave residue)
In these cases, consider doing occasional clarifying rinses with ACV or switching between Castile and a moisturizing natural shampoo.
👎 Pros & Cons
| Pros | Cons |
|---|---|
| All-natural & eco-friendly | Can be drying without rinse |
| Multi-purpose (one bottle = many uses) | May leave residue in hard water |
| No sulfates or synthetic chemicals | Not ideal for all hair types |
| Cost-effective | Requires pH-balancing rinse |
| Easy to customize | Adjustment period for new users |
🛍️ Choosing the Right Castile Soap
Look for:
- Unscented (Baby Mild) for sensitive scalps
- Peppermint or tea tree for oily scalp and dandruff
- Lavender or rose for soothing and floral aromas
Always avoid synthetic additives or artificial fragrances—especially if you’re applying it to your scalp.
Check out our favorite Castile brand here!
🌿 Final Thoughts
Using liquid Castile soap as shampoo is a game changer for many people looking to simplify their routines and detox from chemicals. With the right dilution and a good acidic rinse, it can leave your hair feeling fresh, balanced, and naturally clean.
Like anything, it’s not one-size-fits-all. But if you’re ready to try something different—something more aligned with nature and your body—Castile soap just might be your new favorite shampoo alternative.
🌸 Bonus Tip
Try rotating Castile soap with:
- Clay washes (like rhassoul)
- Herbal hair rinses (like nettle or horsetail)
- Oil treatments for ends (like argan or castor)