Why Deionized Water is Used in Cosmetic Formulation?

 

Why Deionized Water is Used in Cosmetic Formulation?


Water is an essential ingredient in most cosmetic products. In fact, when you read product labels, it is often listed as the first ingredient which means that it forms the highest percentage in the formula. Aside from being used as a solvent, water is one of the effective ways to hydrate the skin and hair.

There are different types of water and each one has its own unique properties. When it comes to formulating cosmetics, the type of water used has an impact to the stability of the final product.


TAP WATER IS A BIG NO-NO!

Just like it’s not usually safe to drink straight from tap water, it’s also not recommended to use it when making your own cosmetic formulations. Tap water is filled with small amount of metal and mineral ions which come from the soil and water pipes. These ions (even at low level) can react with ingredients in your cosmetic formulations. For example, kojic acid is known to react to iron (Fe) ion causing the product to turn into brown color. The presence of metal ions can also destabilize emulsion in lotions and creams.

Take note that although boiling tap water can kill most microorganisms, it won’t eliminate most metal and mineral ions.


DEIONIZED WATER – THE PREFERRED WATER FOR COSMETIC FORMULATIONS

Deionized water is simply water that has metal and mineral ions removed. The process involves water passing through an ion-exchange resin that filters out anions (e.g. sulfate) and cations (e.g. sodium, calcium) present in water. However, this process won’t remove organic contaminants (e.g. pesticides, petrochemicals), bacteria and viruses. That’s why most cosmetic suppliers offer deionized water that is further purified using other filtration systems (e.g. UV treatment) to remove more impurities.


CAN I USE DISTILLED WATER INSTEAD?

In some parts of the world, distilled water might be easier to obtain or is cheaper compared to deionized water. So you might ask, is it OK to use distilled water in cosmetic formulations?

Distilled water is made by boiling water in a still where the collected steam is condensed back to water, leaving behind most of the impurities and microbiological contaminants. However, any contaminants that boil at a lower temperature than water will remain after the distillation process. In other words, it is possible for distilled water to still contain traces of metal and mineral ions that could potentially interact with other ingredients in your cosmetic formulation.

To answer the question, YES you can use distilled water in cosmetic formulations BUT it’s recommended to use a chelating agent such as EDTA that will bind to metal ions present in the distilled water.



CONCLUSION

When formulating cosmetic products, it is recommended to use deionized water to eliminate metal and mineral ions that could affect the stability and performance of the final product. Another option is to use distilled water together with a chelating agent to ensure the absence of mineral ions.

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