PH Buffering Systems In Skincare

First a little disclaimer:

It is important to understand that the content of the document is created in an attempt to educate and it is not representative of the products sold even if products are linked to in the document, if products are linked in this document it is simply to show an example of products that the principles are used in.

Any physiological claims mentioned or linked to in this document are not a reflection on any skincare and are to show the science behind the chemistry.

I will be covering the following questions in this document, what are buffering systems? What is the science behind them? Why are they used in skincare and how can you find them in your skincare? Also why I find this specific subject interesting.

What are pH buffering systems in Skincare?

PH buffering systems are a chemical system used both in nature and reproduced in Cosmetic Chemistry for skincare products. Generally the skincare products that use buffering systems are Cosmeceutical products with highly active ingredients. These Skincare products need to maintain a pH between a very tight range or risk the active ingredient not being readily available.

The basic definition for these systems are systems that can give or take away a hydrogen ion in order to stop the pH from drifting too far.

This maintains a stable condition for the skincare, without the buffer system the pH of the skincare could drift outside of the recommended range and at minimum make the active ingredient less effective.

Skincare is not the only thing that uses pH buffer systems, it is used in a range of products and even occurs naturally (more about that in the below sections).

What is the science behind pH buffer systems?

The science is rather basic but it is often pushed aside as too complicated.
Lets say you have a skincare products with an optimum pH is 5.5 and over time it drifts to 5.7, this would mean there are more free hydrogen ions in the skincare and the buffer system will absorb this hydrogen ion to take the pH back to 5.5. Similarly if the pH drifts to 5.3 then that means there is less hydrogen ions in the skincare and the pH buffer system will donate a free hydrogen ion in order to bring the pH back to 5.5.

In order to do this we require a chemical that can donate or absorb hydrogen ions, this chemical is generally Sodium Citrate.

Sodium Citrate has a molecular structure similarly to sodium bicarbonate. When the Sodium Citrate needs to decrease the pH, it will absorb the hydrogen ion and create more Sodium bicarbonate molecules, when it needs to increase the pH it will donate a hydrogen ion and turn back into Sodium Citrate.

Why buffer systems used in skincare and how can you find them in your skincare?

We probably have already covered this a little but lets get a little more involved in the skincare actives that need to maintain a very tight pH. So the main actives to look for that can benefit from a pH buffer would be your chemical exfoliants such as AHAs which includes lactic and glycolic acids. Buffer systems are also needed in sunscreens due to the long expiry date needed and the requirement for the chemical sunscreen actives to be readily available over the lifetime of the product.

The easiest way to find out whether your skincare product has a buffer system in it is to look at the ingredient list. If it includes Sodium Citrate, it is a good indication that it has a buffer system in the product. The other ingredient to look for can be sodium bicarbonate since sodium bicarbonate can turn into sodium Citrate when combined with Citric Acid this could also be creating a buffer system in the skincare.

What Skincare Products Contain A Buffer System?

One of my favorite skincare products that I believe contains this system is the Medik8 Press and Glow Product. Due to the large amount of BHA present in this product it is important to keep the pH stable so they utilize a pH buffer. 

Why I find pH buffer systems interesting?

The main thing that intrigues me about this system is that it can constantly be changing the amount of free Hydrogen ions in the skincare. Without adding any extra chemicals it automatically corrects pH.

The other interesting point about this system is that it reflects a very similar mechanism that we use in our own blood. We need to ensure a very tight pH in our body to avoid us going into acidosis or alkalosis. Skincare mimics this same system but within the skincare. It is important to understand the mechanism in skincare does not reflect in anyway on our bloods pH but simply that the same process is happening in the skincare as what is happening in our blood.

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Leon Brook

The Vegan Cosmetic Chemist

Cosmetic Chemist
Bachelor of Nutrition student