Does pH in cosmetic formulas really matter?

 

There is a lot of misinformation about pH in cosmetic formulas on the internet, so we’ve put this helpful article together so you can better understand pH in cosmetic formulas, as well as when and why it matters.


One of the great things about the Create Cosmetic Formulas program is you don’t have to worry about when pH is needed, or even what pH is needed, because the program will work this out for you. Just pick and choose the cosmetic ingredients you want to use, and the Create Cosmetic Formulas program will determine the pH needed, and tell you as a method step.


If you are very new to formulating, then please enjoy our FREE cosmetic formulation fundamentals masterclass – click here. This masterclass series is full of helpful tips like these to get your cosmetic formulations off to a great start.

 

Does pH in cosmetic formulas really matter?

pH of cosmetic formulas should always be written as a tight range

When working with the pH of a cosmetic formula, you can never keep it at a specific pH – it will always change over time. In cosmetic formulas you will see pH adjustment written as a method step at the end, for example, ‘adjust pH to 5.3 – 5.8.’ This means the pH should be adjusted, at the end of processing, to within this range. Watch this video to understand how pH is adjusted in a cosmetic formula.


The pH of the formula will then move throughout the product’s shelf life. A stable formula will only move a little bit from its starting point (usually within 10% up or down). If the pH moves too much over the shelf life, then other ingredients in the cosmetic formula could be rendered ineffective and the cosmetic product itself may show signs of separation or other undesirable changes.


Watch this video for more information about how to check the shelf life of your formulas, or learn how to check the shelf life of your formulas with this workshop series.

 

pH of cosmetic formulas must suit the application and ingredients

The pH of the skin and scalp is slightly acidic – around 5.5 – so most cosmetic formulas work best when adjusted to this pH (or very near it). Some cosmetic formulas work better at different pH, however, like hair conditioners, which are best created at a lower pH to ensure strong conditioning activity of the ingredients.


Some ingredients in cosmetic formulas are only biocompatible within particular pH ranges – meaning the ingredient won’t work as it should if the formula is not at the required pH. This means that sometimes you will need to adjust a cosmetic formula to a lower or higher pH to suit the ingredients selected, rather than always being around 5.5.


Don’t worry – water has a neutral pH of 7 and it is perfectly safe for our skin and hair! The Create Cosmetic Formulas program will also check the cosmetic ingredients you choose and give the right pH conditions for your product and cosmetic ingredients selected.


It is only the more extreme pH levels, such as below 3.5 or above 8.5 that start to become quite irritating with prolonged exposure. Formulas needing more extreme pH should only be created by qualified Cosmetic Chemists for safety and regulatory reasons. Find out how to become a Cosmetic Chemist here.

 

Cosmetic formulas should not be diluted to test pH

Because cosmetic formulas are applied to the skin as they are, the pH of the formula must be tested in the finished product, without dilution. This is also important to make sure the actives, preservatives and other ingredients in the formula are also in a compatible environment.


There are a few instances where you may need to dilute a formula to test pH, and this has to do with how the product is applied or its form. For more information on when you might need to dilute a formula to test pH, watch this video or read this blog.

 

Cosmetic formulas where pH is not Relevant

pH is a measure of acidity in a cosmetic formula – but it only exists, or is relevant, where water is the continuous phase. This means you can’t test pH in formulas that are completely oil based (such as balms or oily serums) or where they are mostly oil (such as w/o emulsions and ointments). You also can’t test the pH of powders, such as mineral foundation powders, eyeshadows or blushes.


In these cases, not only is pH not measurable, it is also not relevant – if there is insufficient or no water, then there is no pH.



Create Cosmetic Formulas program takes the guesswork out of pH adjustment

The great thing about the Create Cosmetic Formulas program is that it will work out the best pH for your cosmetic formula based on its application and the ingredients you have selected. Just pick and choose the cosmetic ingredients you want to use, and the Create Cosmetic Formulas program will determine the pH needed, and tell you as a method step.

 

Happy formulating!

 

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