Are Sulfates Bad for The Skin and Hair? Are they Eco-Friendly?
Have you been looking for Sulfate-free shampoo? Did your hairdresser suggest you avoid sulfate? Many bath products are advertised with the word, sulfate-free”. So, what is sulfate and why we need to bother? Sulphate is a group of surfactants and we use quite few personal care products in a bathroom every day. Many of them including moisturizer do contain surfactant. So, if sulfate is harmful or has any health concern, there should be scientific evidence supporting it.
If you don’t need information about each type of surfactant and just want to see the summary, go to the “Conclusion” at the bottom.
What are surfactants and why we need them?
Surfactants (surface-active agent) lower the surface tension between water and the surface of the thing you are cleaning so that water can reach the surface and remove the dirt. When you drop water on a table, you can see the water holding its shape. Surfactants can make the molecules slipperier and less likely to stick to themselves. When we hear “surfactant” we think about bubbles, but surfactants are not only for cleaning. They are also used in many other different products such as fabric softeners, moisturizers, and even foods.
Surfactants have both water loving end and oil loving end, and they are used to stabilize a mixture of multiple materials that usually don’t mix by themselves. For example, Olive oil and vinegar won’t stay mixed in a bottle. But you can add egg yolk as a binder, and the salad dressing will not separate into oil and vinegar.
What types of surfactants do we have?
Anionic surfactants have a negative charge and are excellent for lifting and removing dirt. Sulfate is in this group and a classic example of an anionic surfactant used in personal care products is Sodium Lauryl Sulfate. In the past, “sulfate” has had some negative reputation, irritating to the skin and environmentally toxic. However, these are mostly caused by misunderstanding of scientific data.
If you would like to read more, look at HERE.
You might have used a shampoo contains sulfate caused irritation or dry hair in the past. It could be because the shampoo had a poor formulation rather than just one ingredient. All chemicals have different ways to use safely and how they are used will change the level of risk. For example, water is totally safe to drink and touch, but it is deadly dangerous when we inhale it. Remember, water is a chemical.
Manufacturers are working hard to meet the consumer demands and we now have a wide range of anionic surfactants available including partially natural options. Not all of them are equally same. In fact, some “sulfates” are very gentle to the skin and biodegradable.
Soap is the oldest surfactant in our history and made from animal fat or vegetable oil with alkali containing wood ashes in the past. They are currently made with lye, Sodium Hydroxide, and this made the production cost significantly lower. The chemical reaction called saponification breaks down triglycerides into fatty acids and neutralize into salts. The end result, soap, doesn’t contain any Sodium Hydroxide and totally safe to use.
Soap also contains Glycerine naturally occurring during the production process and it won’t cause drying skin for most people. But it will not moisturize or leave a layer to protect the skin. Some people find soap dries their skin and dermatologists recommend not to use soap for dry skin. This is because soap is high alkaline (pH 9 to 9.8) and it destructs the acid mantle (pH 4.8 to 6), a thin layer of protective film on the skin. This can cause pathogenic bacteria thrives on the skin while the protective film is missing.
Soap is NOT ideal for our hair. Soap will make the hair dry and frizzy because the cuticles on our hair open and the surface gets rough. Soap may also leave waxy residue on hair.
Natural Plant Surfactant
You may have heard Soapwart that contains high level of saponins in all parts of the tree. The extracted saponins from natural plant is generally less harmful to the skin than many synthetic surfactants. It is often used to clean delicate fabrics. There are a couple of things to be aware.
- Woman with vaginal infections should not use soaps or cleansing products made with soapwort.
- If you are pregnant or breast feeding, avoid using since information regarding safety and efficacy is lacking.
- Cleaning effect is low. At this stage, saponins extracted from plant needs more research to improve cleaning effect and reliability.
- Even though saponins is natural, it is toxic for aquatic wildlife. If you want to grow Soapwart, avoid planting it near natural water resource.
These surfactants don’t have any charge and are good at emulsifying oils. They are used for solubilizing oils and fragrances in cream and moisturizer or can be used for low foaming, gentle cleansing. There are some natural alternatives such as Coco Glucoside, Decyl Glucoside, and Lauryl Glucoside.
Amphoteric surfactants both positive and negative charges. They are usually used as secondary surfactants to boost foam and reduce irritation and are widely used from cleaning detergent to body wash. There are no natural alternatives at this time.
This type of surfactant has a positive charge. They have an ability to form electrostatic bonds with damaged protein (negatively charged) which makes the surfactant stick to a surface. They are great for conditioning the surface of skin and hair.
Are Surfactants Environmentally Friendly?
Some surfactants are biodegradable, and some are not. Biodegradable surfactants readily dissolve in water and can be broken down into non-toxic substances by microorganisms. For surfactants to be considered 100% biodegradable by the Environmental Protection Agency (EPA), they must not only degrade in water but also not create known carcinogens or mutagens.
However, any of surfactants even natural ones are harmful to the environment, particularly aquatic ecosystems. When we use cleaning or personal care products in our home, they go into a drain. Then, they will go through WWTP (Waste Water Treatment Plant) before reaching natural water resources. This will make sure almost all chemicals are biodegraded and no negative impact on aquatic wildlife. So, don’t ever dispose of soapy water or wash off chemicals into natural water resources directly.
There will be some cases you will use chemicals outside a house building. For example, when you wash your car in front yard, make sure to dispose of the water on grass at least 60 meters away from a storm water drainage. Surfactants need oxygen and microorganisms to biodegrade. 100% biodegradable products will degrade faster and are better choice.
Here is a comparison of some surfactants
|Plant Oil, Animal Fat, Sodium Hydroxide
|9.3 – 9.8
|Yes for dry skin
|Soap bark, Soapwort, Yucca, etc.
|Coconut, Palm, and Sugar
|11.5 - 12.5
|Sodium Lauryl Sulfate
|Petroleum oil or Coconut/Palm oil
|6.5 – 7.5
|Depends on the usage
|Sodium Coco Sulfate
|Coconut, Palm oil
|7.5 – 10.5
|Sodium Cocoyl Isethionate
|6 - 8
Almost all surfactants are synthetic. Many of them are partially derived from renewable natural resources such as vegetable oils but are not 100% natural. The production process involves chemical reaction which requires synthetic material. If you see “100% natural” claim on the product, you may need to do a bit research.
You may see “non-sulfate” or “sulfate-free” on many products. The fact is sulfate itself doesn’t make shampoo or body wash irritating or harmful. Sulfates are a group of surfactants and there is no scientific evidence to say they are unsafe or harmful when they are used within regulated amount. There are no data show the health concerns associated with using sulfates. Also, all sulfates are not equally made. Some are very gentle to the skin and 100% biodegradable.
Most surfactants going through Waste Water Treatment Plant via a drainage in a house will be broken down into non-toxic substances before reaching the ocean. 100% Biodegradable products are better, but they are still harmful to the environment if disposed of directly into natural water resources.
It is impossible to judge the performance of the product by looking at only 1 ingredient such as sulfate. Formulating a body wash or shampoo is much more than what surfactant to use.
If you are interested, look at How to Read Beauty Product Labels