Looking at a Bubbles & Balms Shampoo Bar with lots of bubbles in a clawfoot tub.

Syndet vs. Soap Shampoo: What You Need to Know

The world of shampoos can be a confusing one. Foaming, special-treating, volumizing, clarifying – what on earth does it all mean?!

Many of us get overwhelmed and shrug, deciding shampoo is shampoo no matter the claim, formulation, bottle/bar, or brand. But this is far from the truth, as shampoos vary significantly! 

Instead of getting caught up in endless marketing claims, we can learn the basics of different shampoos (i.e., ingredients and types of formulations). For example, two common types of shampoo bars are soap-based and syndet. 

To start this conversation, we wanted to share an easy explainer on syndet vs. soap shampoo, and why it’s important to know the differences.  

Up first: soap-based shampoo bars. 


What are soap-based shampoo bars?

Solid soap-based shampoos are similar to hand and body bar soaps. They are typically made via cold process – a soap-making method.

Cold process shampoo bars are made when fats (usually oils) are mixed with sodium hydroxide (often known as lye). Once combined, a chemical reaction occurs called saponification. And ta-da – you have soap!

We love this method for soap bars! For shampoos? Not so much…  

Our scalp has a pH of 5.5, and hair shafts are 3.67 (both acidic). Soap-based shampoo bars, however, are alkaline due to their high pH of 9-10. Why does this matter?

Using alkaline shampoos (liquid or bar) disrupts our scalp’s microbiome, which can lead to irritation, redness, waxy hair buildup, and a dry or flaky scalp. What’s more, using a high-pH shampoo causes cuticle damage, frizz, and hair fiber breakage.

A key role any shampoo should play is sustaining healthy pH levels, and luckily, science knows what works. 


What are syndet shampoo bars?

Syndet shampoo bars, like soap, use surfactants to cleanse. But, rather than create the surfactants by saponification, syndet bars use surfactants synthesized from a variety of sources. This can be bad AND great for the skin!

As you can imagine, it’s not up to essential oils to do the deep cleansing for the scalp. That job goes to surfactants (soap or otherwise)! Surfactants are cleansing agents that remove excess hair oils, dirt, and scalp buildup. 

Some surfactants are derived synthetically, and some are of natural origin. For example, a not-so-good surfactant is sodium lauryl sulfate (SLS), which is often made from petroleum. SLS is well-recognized as a skin irritant, but it is still commonly used in soaps and shampoos.

Joyfully, cosmetic science has created a world with the most wonderful surfactants, too! 

Plant-based surfactants are derived from nature, like soap nuts, palms, or coconuts (ours come from coconuts). They are mild cleansers (not harsh on the scalp) but still incredibly effective at washing hair.

We recommend syndet shampoo bars made with gentle-cleansing surfactants, like sodium cocoyl isethionate, which is synthesized from coconut oil. Syndet bars are especially needed for those with sensitive skin. 


Syndet shampoos for sensitive skin  

Well-formulated syndet shampoo bars are the best option for our scalp and hair because gentle surfactants are milder than soap. But gentle-cleansing syndet bars are extra important for those with sensitive skin or skin conditions, such as atopic dermatitis (often called eczema).

Let’s cover a few reasons why syndet shampoo bars are ideal for eczema and sensitive skin: 

  1. They are the gentlest cleansing shampoo  
  2. They are less drying and unlikely to aggravate inflamed skin
  3. They enable healing during flare-ups 
  4. They maintain the scalp’s natural pH & thereby support the skin microbiome
  5. They lather well & smell amazing (well, ours do!)

Bubbles & Balms shampoo bars

Skin sensitivity is our main criteria behind how we formulate each product here at B&B. Our passion grew as we noticed the shortage of products for sensitive skin, despite how many people suffer from eczema, rosacea, dermatitis, or general skin sensitivities. 

We all know shampoo is a pillar product, so we formulated our well-loved and sensitive skin-approved syndet shampoo bars. They are made with gentle coconut-derived surfactants. And, importantly, they are free from parabens, synthetic fragrances, synthetic preservatives, sulfates, phthalates, and gluten.

Beyond scalp health, choosing shampoo bars protects the environment and ecosystems as they are both chemical and plastic-free. Plus, our shampoo bars last between 60 and 90 washes (more than your average bottled shampoo!). 

We currently have three hair-luscious bars to try: Tea Tree & Charcoal, Rosehip & Lavender, and Coconut Orange.

We are sure you’ll never look back after adopting a shampoo bar! However, we do offer a money-back guarantee, so you can test the sudsy waters risk-free.  


Shop our shampoo bars here! 


- Written by Sariah Vilate

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