In my 20 years as a hair stylist, I've seen countless products come and go, but few have inspired the dedicated following of Dr. Bronner's Castile Soap. While it wasn't created specifically for hair, many of my clients ask: "Can I really use Dr. Bronner's as shampoo?" Let's dive into what makes this multipurpose soap both appealing and potentially challenging for your locks.
What Makes Dr. Bronner's Different?
Dr. Bronner's Castile Soap is essentially a concentrated vegetable oil-based soap that comes in several scent variations, with peppermint being the most iconic. The appeal isn't just in its versatility (18-in-1 uses, as the colorful label proclaims) but in its commitment to organic ingredients and ethical sourcing.
Unlike conventional shampoos loaded with silicones, sulfates, and synthetic fragrances, Dr. Bronner's offers a stripped-down approach with ingredients you can actually pronounce. For those seeking to simplify their routine or reduce plastic waste, it's understandably tempting.
The Science of Soap on Hair
Before you dump your shampoo collection, it's important to understand what happens when you wash your hair with soap instead of shampoo:
- pH Difference: Your hair and scalp have a naturally acidic pH around 4.5-5.5. Dr. Bronner's has a pH of about 8.9-9.0, which is alkaline. This pH difference can temporarily lift your hair cuticle, leaving it feeling rough or "squeaky."
- Oil Removal: Castile soap is incredibly effective at removing oils-sometimes too effective, stripping away the natural oils your hair needs for protection.
- Hard Water Reactions: When used in hard water areas, the minerals can react with the soap to create a waxy residue that builds up on hair over time.
How to Use Dr. Bronner's as Shampoo (If You're Determined)
If you're set on giving it a try, here's my professional approach to minimize potential issues:
- Dilute properly: Start with a 1:10 ratio-one part soap to ten parts water in a separate bottle. Using it full-strength is far too concentrated for hair.
- Focus on the scalp: Apply primarily to your scalp and massage gently. The runoff will clean your lengths sufficiently without over-stripping.
- Follow with an acidic rinse: This is non-negotiable! Mix 1-2 tablespoons of apple cider vinegar or lemon juice with a cup of water and pour it over your hair after rinsing out the soap. This helps restore your hair's natural pH.
- Deep condition regularly: Using a weekly deep conditioning treatment will help maintain moisture balance.
Who Should Consider Using Dr. Bronner's on Hair?
In my professional experience, Dr. Bronner's works best for:
- People with naturally oily hair and scalps
- Those with relatively short hairstyles
- Individuals with soft water in their homes
- Those committed to following up with proper acidic rinses
- People looking to simplify their routines and reduce product consumption
Who Should Probably Skip It
I typically caution against using Dr. Bronner's as shampoo if you:
- Have colored or chemically treated hair
- Deal with dryness, brittleness, or frizz
- Have curly or highly textured hair that needs moisture retention
- Live in a hard water area without a water softener
- Don't have time for the extra acidic rinse step
My Clients' Experiences
Over the years, I've had clients experiment with Dr. Bronner's with varying results. Sarah, who has fine, straight hair, loved the volume she got from using the peppermint variety diluted with water. Meanwhile, Marcus found that after an initial "detox" period of slightly oilier hair, his scalp's oil production actually balanced out.
However, my client Jasmine with color-treated curly hair experienced significant dryness and color fading after just two washes, despite following all the recommended steps.
The Bottom Line
As with most hair care questions, there's no one-size-fits-all answer. Dr. Bronner's can be a wonderful option for some hair types and a disaster for others. If you're curious, start with a patch test and be prepared to adjust your routine-or abandon ship if necessary.
Remember that traditional shampoos were developed specifically for hair, with pH levels and ingredients designed to maintain your hair's integrity. Sometimes the specialized tool really is the best one for the job.
Have you tried Dr. Bronner's as shampoo? I'd love to hear about your experience in the comments below!