Preserving cosmetic formulations

Dec 5, 2023 | The basics

Have you ever heard that some cosmetic products are “preservative free” or some brands just don’t use any preservatives because they are harmful? This is actually not true and we should look at the preservatives more closely.



Preservatives are ingredients that prevent cosmetic products from contamination. They are usually used in water-based formulations, but they can be used in anhydrous products as well. Preservatives prevent the growth of microorganisms such as bacteria, mold and yeast. And they will grow if the conditions are suitable for them.

Preservatives are usually blends of certain ingredients that prevent microorganism growth. This information can be easily seen in the INCI name. If you see only one ingredient in the INCI, then you should add some other ingredient which would complement it.

If you see several names in the INCI – it is a blend and it may be a broad spectrum preservative. Everything depends on the ingredients and their efficacy.

There are some exceptions when the preservatives are not needed, however in most cases a preservative is a must.

Here are some formulations that don’t need a preservative:



It is possible to have a “preservative free” cosmetic product? Because as you know, unpreserved products will go bad in days if they don’t have a preservation system.

So, “preservative free” is a more complicated approach were different things were applied to reach this point where one could market the product as free of preservatives.

It really depends on the product itself and it usually comes as a “hurdle” approach (but not necessarily) where you try to limit active water content. For example, preservatives are not needed:

  • in soaps due to high pH (9-10). The high pH creates unwelcoming environment for the microorganisms and you will never see a traditional soap made with preservatives. But our skin’s pH is actually 5-5.5 and using pH of 9 would lead to high irritation, so this approach is not suitable for other cosmetic products.
  • in glycerites or in other extracts where there is high glycerin (or other glycols) amount (at least 40%). But these products are extremely sticky and not pleasant to use. Also, these are usually concentrated extracts which can be an irritant to the skin.
  • in products that contain at least 20% ethanol. These products are usually disinfectants and you would not want to use it on your face as it would be extremely drying.
  • honey by itself is preserved. However, it becomes tricky when it is diluted with something else. If you have ever tried to add a drop of water to honey, you will know that it will go bad pretty quickly. (I know honey is not vegan, but I feel that I must clarify the confusion that may arise as there are millions of products out there and some have honey as well).

As you can see, there are some cosmetic products or raw ingredients that would not need preservatives, but they are based on other approach (limiting water activity). These ingredients are not preservatives by themselves, they just have additional capabilities at high amounts. And they only are useful in some areas.



Another way where cosmetic brands may tell that they do not actually use preservatives is that they will use ingredients that have dual capabilities. For example, glycols are good humectants, but they also serve as preservative boosters. These ingredients will not be listed as preservatives due to their other abilities and the brand can market the product as “preservative free”. You can check the ingredient functions at CosIng website.

A good example of an ingredient with a dual purpose would be pentylene glycol. It is a very good humectant, typically used in 1-5%. At 3% it is used as a preservative booster and at 5% it gives its full preservative effect. But that does not mean it should be used alone as a preservative.

Another example of preservative booster is glyceryl caprylate which also has a refatting and wetting ability. It is not registered as a preservative as it would be too mild used alone. But when using with other similar ingredients it will form a preservation system that is enough for a product to protect from growing microorganisms.

Also, packaging and good manufacturing practice are important for creating a good product that can protect against bacteria, mold and fungi. So, there are a lot of factors that come into play when creating a preservation system, but cosmetics products are generally made with preservatives, even when they are not that easily recognized.



This is a checklist with essential equipment for making DIY cosmetics to help you get everything you really need.


There is a myth going on that preservatives are harmful and toxic. Parabens are usually mentioned here and we all know that they are demonized. But some of them are still marked as safe to use ingredients in cosmetics and there are a lot of cosmetic products formulated with them.  

Actually, all cosmetic ingredients are tested to see if they could be used and then at what amount they could be used. Which means they are not toxic when used at the right amount and in way they should be incorporated into the product.

And yes, some parabens such as methylparaben, propylparaben, butylparaben also made into this list. However, the question if they should be used really depends on the formulator and on the people who will be using the products made with them.

If you are not a fan of parabens, there are hundreds of other preservatives that could be used.
The thing with the parabens is that they are very effective at low dosages which can be tricky to weight when the batch size is very small. Also, it is actually quite hard to find a place where to buy them (at least for small formulators).



But there is an alternative to use other milder preservatives which are usually not that effective and can be tricky to work with. As they are not that potent, you will need to use them in higher amounts and this also comes at the cost as the greener preservatives are always more expensive.

Another thing is that other preservatives may not be broad spectrum which means they do not protect well enough from bacteria, yeast and mold. And there should be a lot of research and testing done using these milder materials. But it is possible to make cosmetics with them, it just means it will be more challenging.


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