Can Natural Cosmetics be Preservative Free?
There is a controversy in the cosmetic industry around the fact that everyone seems to have a problem with preservatives.
No one likes to use them, but almost all cosmetic companies include them.
We do not like them because of the idea that they are carcinogenic or harmful. This is what has led everyone to be against chemicals that are a “preservative”.
There are many substances that have preservation properties. For example, parabens, sodium benzoate, and alcohol are often used.
Even there are some more natural options approved by ECOCERT such as Geogard® or Germall® Plus.
Although there is no scientific proof that preservatives cause the alleged adverse effects (in some cases). The trend against them is very popular.
There are a lot of people that choose their cosmetic products by avoiding parabens.
Even some people support the use and production of preservative-free cosmetics. This idea leads us to ask:
Is it possible to create a preservative-free cosmetic?
To answer this, we will describe the following strategies for avoiding cosmetic contamination:
- Good manufacturing practices
- Primary packaging in cosmetics
- Water activity level
- Type of emulsion
- pH control
- Ingredients that improve preservation
I will not address the acceptance of preservatives in natural cosmetics. That is a topic for another article.
Good Manufacturing Practices
Following GMP is one of the best preventive strategies against microbial contamination. It is a must for every natural cosmetic company.
The production of cosmetics in a contamination-free environment boosts their shelf life. This in turn guarantees safety and proper conditions for the end customer.
GMPs are established in ISO 22716:2007. Following the guidelines reduces the possibility of microbial contamination.
But, despite this, it is not possible to ensure that our products are completely sterile. For this reason, other strategies help ensure the safety of the cosmetics.
Best Container for cosmetics
One way to prevent cosmetics from becoming contaminated is to use containers that prevent the entrance of microbes.
These containers can vary from bottles that have a dispenser, to squeeze bottles.
Containers that do not prevent contact with the product are those that have to be opened when using the product. For example, all the different types of jars.
The use of a closed container provides protection against contamination due to use. But not all closed containers prevent the incorporation of air into the system. This can also impact the products.
Dispensing pumps incorporate air into the system to function, which involves potential contamination. There are containers that allow dosing in vacuum systems, avoiding contact of the product with the air.
The type of container also depends on how good the formulation is against contamination. There are many cosmetic brands that use jars and the product is stable for a long time.
Water activity level
In this article, we do not explain in depth what is the level of water activity (aw) in cosmetic products. I will write more about this in another article.
Since water provides the perfect medium for the growth of microorganisms. It is necessary to control the amount of available water that they can use.
This is known as the water activity level in a formulation.
In cosmetics, water often represents up to 80% of the product, which makes them very susceptible to microbial contamination.
To reduce water availability, it is necessary to incorporate certain ingredients. For example:
- Chelating agents such as EDTA
- Salts
- Polyols such as sorbitol or glycerin
- Amino acids
- Hydrocolloids such as Guar or xanthan gum
- Sodium polyacrylate
The choice depends on the formulator and the type of cosmetic product. These can provide different characteristics to the final feeling of the formula.
In natural cosmetics, not all those mentioned above are approved.
A water activity level of 0.8 can assure microbial stability in some cosmetic products. Without the need for preservatives.
Yet, the cosmetics used to prove this were made in aseptic, and controlled conditions. Something that is often not achieved in natural cosmetics.
Emulsion Type
As mentioned in the previous section, many cosmetics are made with a large amount of water (around 80%). These are in most cases O/W emulsions (lotions).
But in the world of cosmetics, there are other types of emulsions in which the continuous phase is oil (W/O). With these products, we can limit the contamination of microbes.
This is because W/O emulsions have a much lower amount of water, and it is not all available to bacteria.
The use of this type of emulsion is uncommon, but they are an option to produce preservative-free products.
pH value
pH plays a very important role in natural cosmetics.
The ideal range for the growth of microorganisms is between 5 and 8 on the pH scale. Thus, cosmetic products that fall outside this range could be self-preserved.
In fact, the only products free of preservatives (guaranteed) in natural cosmetics are saponified soaps. This is because the final pH is usually between 9 and 10 (harsh for bugs to grow).
But, keep in mind that there are some makers that do include preservatives. It is the brand’s choice.
It has also been recognized that some formulations with pH values between 3.5 and 4.5 are more stable against microbial contamination.
These products are usually hair conditioners or contain salicylic acid in the formulation.
Yet, it is not possible to fully trust that the effect of a more acidic pH will allow us to keep the stability of a cosmetic product.
There are bacteria that are capable of growing beyond the ranges already mentioned. So a combination of strategies is needed to ensure product safety.
Ingredients that improve preservation
As there are ingredients that cause a product to go bad faster. There are also those that help preserve and stabilize a formulation.
In the cosmetic industry, there is a whole range of preservative Boosters.
The function of these is to improve stability, provide greater protection, and reduce the needed quantity of preservatives.
The advantage of buying a marketed booster instead of using the individual ingredients is the fact that some are approved by ECOCERT.
Their efficacy has been evaluated, so you can trust the end result of including them in the formulation.
If you don’t want to buy a product as such, you can also use some of these natural alternatives:
• Caprylic or capric alcohol
• Griceryl caprylate
• Ethylhexylglycerin
The reason why they are boosters is that they can slow down bacterial growth. They cause disruptions in the membrane of these organisms.
There are essential oils with antimicrobial properties such as tea tree, rosemary, cinnamon, grapefruit, or grapefruit seed extract.
But, none of these natural extracts will provide broad-spectrum protection, and their effect is also limited. Thus, it is not recommended to use them as preservatives.
Conclusion
Returning to the question, is it possible to create a preservative-free cosmetic?
I believe not. At least in my opinion.
Despite having the best manufacturing conditions and an optimized system with all the strategies mentioned in this article, microorganisms are very stubborn.
Since we can not guarantee that there is no growth by microorganisms. The safety of the consumer is also not guaranteed. Something that is not acceptable.
As cosmetic formulators, we must ensure that all products are safe for the consumer. This is our priority.
Although the idea of not using preservatives is attractive, I do not recommend in any circumstance omitting them.
I recommend using the strategies mentioned to improve the security of all the products you make.
I hope that this article has been helpful to understand the different strategies that improve the stability of a cosmetic. If you liked it, please share it on your RSS.
Sources of information
https://ascc.com.au/preservatives-used-in-personal-care-products-2/
https://pubmed.ncbi.nlm.nih.gov/24117694/
https://www.mdpi.com/1420-3049/23/7/1571
https://chemistscorner.com/natural-cosmetic-preservative-ingredients-and-strategies/
