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Choosing the Surfactants in a Great Shampoo Bar

A Display of Soaps at Ziryab's Shop

Look for great shampoo surfactants when searching for the perfect shampoo bar for you. What is the most important thing to you in a shampoo bar? Must it be 100% natural? Make your hair look magnificent? Before being swayed by the cool additives in the soap, look at the surfactants. In shampoo bars these are normally either soaps or synthetic detergents (and sometimes herbs like Yucca or Soap Nuts). Surfactants break the water tension and allowing dirt and oil to be lifted from the hair.

Three Types of Common Surfactants in Shampoo Bars.


These are often considered 100% natural although this could be argued. They are made using any kind of oil or fat and adding water and a very high alkaline substance of Potassium Hydroxide, Sodium Hydroxide (Lye) or occasionally something that can be made using ashes called caustic potash. African Black Soap is traditionally made with handmade caustic potash. Caustic Potash is chemically a rough form of Potassium Hydroxide. Neither of these chemicals remain in a properly made soap. Because of consumer distaste for chemical sounding ingredients, artisanal soap makers have taken to listing the ingredients as saponified oils instead of listing the   chemical. This is, as far as I understand, legal since neither chemical remains after the soap making process is complete.  

Pros and Cons of Lye Based Shampoo Bars


Traditional lye soap based shampoos are okay for the environment as they degrade quickly. Small animals and fish can’t be exposed to soap in their water because of the alkalinity so only use soap away from open water and running streams.


The high alkalinity of traditional soap means it isn’t a gentle cleansing substance. And adjusting lye-made soaps destroys the soap and its cleansing ability. Lye soap works best in softer water. 


Using soap in hard – mineral rich – water can leave a mineral residue on hair. Neither of these drawbacks are necessarily bad for all people.  People with undamaged hair actually benefit from roughing up their hair cuticle a bit, giving them fuller hair. Also, mineral deposits on hair make hair feel thicker and heavier. For those with thin, undamaged hair, this might be perfect. 


For those who want to use the most natural shampoo bar, drawbacks of natural soap can often be addressed by rinsing with soft water, rain water or distilled water. Adding a small amount of acid like vinegar to the rinse water, helps too. Both will balanced the hair’s Ph and rinse much of the mineral build-up away.  


One other aspect of natural lye is that some soap makers formulate soap and shampoo with extra oils that remain unsaponified. Depending on how much oils remains and the type of oil – hair will either like it or not. To know this detail, you will probably contact the shampoo bar maker who will know. I choose to have high-end oil in my shampoo bars which I add at the end so the best oils (argan and jojoba) remain available for hair.  However, this is not perfect for every hair type. 

I make these kind of shampoo bars because my husband, among others, loves them. He likes the Rosemary Old Fashioned Natural Shampoo Bar best.  If you’ve ever used Dr. Bronner’s as a shampoo, you know have an idea of what a lye shampoo is like.

Unlike Dr. Bronner’s, mine is a solid soap and while it lasts as long or longer, it requires less packaging. Also, when you see a clear soap like Dr. Bronner’s , you can be fairly certain there isn’t a lot of extra oil or butter in the soap. Clear soaps tend to be very cleansing but not very moisturizing. Some people like that, others don’t.

NEW FANGLED SHAMPOO BAR SURFACTANTS:  Sulfate based Synthetic Detergents

These shampoos use synthetic detergents (syn-det) introduced in the ’30s and became very popular during WWII when there was a shortage of oils and fats.  They are used in place of lye-soap because they tend to be gentler, have a lower Ph and work well in hard water without leaving residue. 

Some syn-det shampoo bars have been Ph balanced but not all.  Ph balanced syn-det shampoos are better for hair, especially if you are trying to grow it long.   

Many shampoos, especially ones that were developed a long time ago, often contain sulfate based detergents. 

Sulfates probably have a worse reputation then they deserve.  For example, Sodium Lauryl Sulfate (SLS) is made from 100% plant derived ingredients and therefore has an excellent bio-base, meaning it converts back to natural ingredients fairly easily once it biodegrades, which it does fairly easily.   

On the other hand, most sulfates, especially SLS, are harsher than some alternative detergents. Great for washing dishes but often harsher than you want for color-treated or for keeping hair as undamaged as possible.  

Other things to keep in mind, Sodium Lauryl Sulfate is pretty much the least expensive of the synthetic detergents available for shampoos so if you are purchasing one with SLS, it is probably less expensive than others but not always. Sodium Lauryl Sulfate is the primary ingredient in many of Lush’s 2 oz bars – which sell for about 10 or 12 dollars. Mind you, that’s probably a better deal than your store bought shampoos since Lush says their bar lasts 80 washes.  If purchasing a Sodium Lauryl Sulfate (SLS) in a shampoo bar from a hand-maker, check to see if there is an ingredient that lowers the Ph because SLS is too high a Ph to be used without Ph adjustment.  Citric Acid is a common Ph adjuster.   


Sulfate-free shampoos tend to be gentler, better for keeping hair undamaged, better for colored hair, better for Black hair, and I suspect, better for most hair except those who really want their hair CLEAN above all else – even in this case there are better alternatives. People think they may be safer to use and better for the environment. I am not convinced this is the case with all alternative detergents.  These kinds of detergents tend to be more expensive though. 

With alternative synthetic detergents, do not follow the logic that the simpler the ingredient list the better or more natural. This is not true when it comes to a shampoo. Often surfactants (synthetic detergents) work together to make a shampoo milder. When they are alone, they can be harsher than when they are together.  For instance I use Sodium Cocoyl Isethionate and Cocamidopropyl Betaine together and they work much better together than apart. 

There’s much more to say about the surfactants in a great shampoo bar but this the base you must know in choosing a shampoo wisely that meets your criteria.  

I personally think my Yucca Shampoo Bar with Oats is the best shampoo bar for both environment and hair health and hair beauty but I am biased. 

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