Cosmetic preservation is a fundamental aspect in the development of any cosmetic formulation. Creams, serums, shampoos, gels or lotions can provide favourable conditions for the growth of microorganisms such as bacteria, yeasts and moulds, especially when they contain an aqueous phase.
A properly designed cosmetic preservative system helps protect the formulation against microbiological contamination during manufacturing, storage and use by the consumer.
However, choosing the right preservative is not simply a matter of selecting an antimicrobial ingredient. Factors such as pH, water activity (Aw), solubility, formulation composition, manufacturing process and packaging type can significantly influence its effectiveness.
For this reason, preservation should be approached as an integral part of formulation development.
Other preservatives such as Phenoxyethanol, isothiazolinones, Iodopropynyl Butylcarbamate (IPBC), DMDM Hydantoin, Imidazolidinyl Urea or Benzyl Alcohol have also been used in numerous formulations.
However, market developments, regulatory changes and evolving consumer preferences have driven the development of new cosmetic preservation strategies.
There is currently growing interest in formulations featuring concepts such as:
Each product has specific physicochemical and microbiological characteristics, so different parameters must be considered when selecting the preservative system.
Products such as:
In contrast, certain anhydrous formulations, such as some oils, balms or sticks, may present a lower microbiological risk.
For this reason, water activity is one of the parameters that should be considered when assessing the microbiological risk of a cosmetic formulation.
A particularly important example is organic acids, whose antimicrobial activity depends to a large extent on the pH of the formulation.
Other preservative systems may remain active across a broader pH range.
Therefore, defining the target pH from the early stages of development facilitates the selection of a compatible and effective preservation system.
A poorly solubilised preservative or one that is inadequately distributed between the different phases of an emulsion may have reduced effectiveness.
When selecting a preservative system, aspects such as the following should be considered:
Ingredients such as:
These interactions should be evaluated in the final formulation and may require adjustment of the system concentration or the incorporation of multifunctional ingredients acting as preservative boosters.
Certain raw materials used in preservation systems may be sensitive to high temperatures and may need to be incorporated during the cooling phase.
Therefore, before selecting a preservative, it is advisable to consider:
An airless container, for example, limits the product's exposure to the environment and direct contact during use.
In contrast, a wide-mouth jar may result in greater exposure during use, as consumers may repeatedly introduce their fingers into the product.
The selection of the preservative system should therefore consider both the characteristics of the formulation and the packaging and intended conditions of use.
One strategy that is gaining increasing relevance is the use of multifunctional ingredients capable of providing different benefits within the same formulation.
Some of the molecules used in these strategies include:
Their use can enable the design of strategies in which different mechanisms work together, optimising the microbiological protection of the product.
This approach is particularly interesting in formulations where the aim is to:
Two apparently similar formulations may exhibit different microbiological behaviour due to small variations in pH, water activity, the ingredients used, the manufacturing process or the packaging.
For this reason, the effectiveness of the preservation system should be evaluated in the final formulation when appropriate according to its microbiological risk assessment.
One of the main tools used is the Challenge Test, or preservative efficacy test.
The ISO 11930 standard establishes a reference methodology for evaluating the antimicrobial protection of a cosmetic product.
During this test, specific microorganisms are inoculated into the product and their evolution is monitored over a defined period, making it possible to assess the formulation's ability to control microbiological contamination.
The Challenge Test can be used to:
The system should be specifically evaluated for each formulation.
In certain formulations, they can be used alongside other antimicrobial components to develop synergistic systems and optimise microbiological protection.
The appropriate alternative will always depend on the characteristics of the formulation.
For this reason, the target pH should be considered from the early stages of development.
ISO 11930 is one of the main reference standards used for this evaluation.
Our aim is to help formulators find the most appropriate solution according to the specific characteristics of each project.
We can provide support with:
At LEMMEL, we have extensive experience in the distribution of raw materials for the cosmetics industry and work closely with R&D departments to identify solutions adapted to their specific requirements.
Are you developing a formulation and looking for the right preservative system? Contact our technical team and we will help you evaluate the alternatives available for your project.
A properly designed cosmetic preservative system helps protect the formulation against microbiological contamination during manufacturing, storage and use by the consumer.
However, choosing the right preservative is not simply a matter of selecting an antimicrobial ingredient. Factors such as pH, water activity (Aw), solubility, formulation composition, manufacturing process and packaging type can significantly influence its effectiveness.
For this reason, preservation should be approached as an integral part of formulation development.
The evolution of cosmetic preservatives
For many years, parabens have been widely used in the cosmetics industry due to their antimicrobial efficacy, broad spectrum of activity and competitive cost.Other preservatives such as Phenoxyethanol, isothiazolinones, Iodopropynyl Butylcarbamate (IPBC), DMDM Hydantoin, Imidazolidinyl Urea or Benzyl Alcohol have also been used in numerous formulations.
However, market developments, regulatory changes and evolving consumer preferences have driven the development of new cosmetic preservation strategies.
There is currently growing interest in formulations featuring concepts such as:
- Paraben-free
- Preservative free
- Clean Beauty
- Natural Origin
- Simpler ingredient lists
How to choose a cosmetic preservative?
There is no universal cosmetic preservative suitable for every formulation.Each product has specific physicochemical and microbiological characteristics, so different parameters must be considered when selecting the preservative system.
Water activity (Aw)
Water activity, or Aw, indicates the amount of water available in a formulation that can support the growth of microorganisms.Products such as:
- Creams
- Gels
- Shampoos
- Lotions
- Water-based serums
In contrast, certain anhydrous formulations, such as some oils, balms or sticks, may present a lower microbiological risk.
For this reason, water activity is one of the parameters that should be considered when assessing the microbiological risk of a cosmetic formulation.
Formulation pH
pH can directly influence the effectiveness of certain preservatives.A particularly important example is organic acids, whose antimicrobial activity depends to a large extent on the pH of the formulation.
Other preservative systems may remain active across a broader pH range.
Therefore, defining the target pH from the early stages of development facilitates the selection of a compatible and effective preservation system.
Solubility and preservative distribution
Simply adding a preservative to a formulation is not enough: it must be properly distributed in the phase where it needs to exert its activity.A poorly solubilised preservative or one that is inadequately distributed between the different phases of an emulsion may have reduced effectiveness.
When selecting a preservative system, aspects such as the following should be considered:
- Water solubility.
- Oil solubility.
- Partition coefficient.
- Type of emulsion.
- Compatibility with surfactants and emulsifiers.
Interaction with other cosmetic ingredients
The effectiveness of a preservative system can also be influenced by other components present in the formulation.Ingredients such as:
- Proteins.
- Botanical extracts.
- Clays.
- Surfactants.
- Polymers.
- Electrolytes.
These interactions should be evaluated in the final formulation and may require adjustment of the system concentration or the incorporation of multifunctional ingredients acting as preservative boosters.
Temperature and manufacturing process
The manufacturing process must also be taken into account.Certain raw materials used in preservation systems may be sensitive to high temperatures and may need to be incorporated during the cooling phase.
Therefore, before selecting a preservative, it is advisable to consider:
- Maximum process temperature.
- Phase of incorporation.
- Exposure time to high temperatures.
- Compatibility with the rest of the manufacturing process.
Packaging type and conditions of use
Cosmetic packaging also forms part of the preservation strategy.An airless container, for example, limits the product's exposure to the environment and direct contact during use.
In contrast, a wide-mouth jar may result in greater exposure during use, as consumers may repeatedly introduce their fingers into the product.
The selection of the preservative system should therefore consider both the characteristics of the formulation and the packaging and intended conditions of use.
New trends in cosmetic preservation
Cosmetic preservation is evolving towards systems that are increasingly adapted to the specific requirements of each formulation.One strategy that is gaining increasing relevance is the use of multifunctional ingredients capable of providing different benefits within the same formulation.
Some of the molecules used in these strategies include:
- Caprylyl Glycol
- Pentylene Glycol
- Ethylhexylglycerin
- Phenethyl Alcohol
- Organic acids
- Different synergistic combinations of multifunctional ingredients
Preservative boosters and multifunctional ingredients
So-called preservative boosters can be used to enhance the performance of a formulation's preservation system.Their use can enable the design of strategies in which different mechanisms work together, optimising the microbiological protection of the product.
This approach is particularly interesting in formulations where the aim is to:
- Reduce the concentration of certain traditional preservatives.
- Develop milder preservation systems.
- Formulate paraben-free products.
- Adapt to Clean Beauty concepts.
- Incorporate multifunctional ingredients.
- Simplify the ingredient list.
Challenge Test and ISO 11930: how to validate a preservative system
The selection of a preservative should not be based exclusively on its theoretical characteristics.Two apparently similar formulations may exhibit different microbiological behaviour due to small variations in pH, water activity, the ingredients used, the manufacturing process or the packaging.
For this reason, the effectiveness of the preservation system should be evaluated in the final formulation when appropriate according to its microbiological risk assessment.
One of the main tools used is the Challenge Test, or preservative efficacy test.
The ISO 11930 standard establishes a reference methodology for evaluating the antimicrobial protection of a cosmetic product.
During this test, specific microorganisms are inoculated into the product and their evolution is monitored over a defined period, making it possible to assess the formulation's ability to control microbiological contamination.
The Challenge Test can be used to:
- Evaluate the effectiveness of the preservative system.
- Detect potential interference from the formulation.
- Compare different systems or concentrations.
- Optimise the preservation strategy.
- Help demonstrate the microbiological protection of the product.
Frequently asked questions about cosmetic preservatives
What is the best preservative for cosmetics?
There is no single preservative suitable for every formulation. The choice depends on factors such as pH, water activity, ingredients, manufacturing process, product type and packaging.The system should be specifically evaluated for each formulation.
What are preservative boosters?
Preservative boosters are ingredients that can help improve the performance of the preservation system.In certain formulations, they can be used alongside other antimicrobial components to develop synergistic systems and optimise microbiological protection.
Can cosmetics be formulated without parabens?
Yes. There are numerous alternatives and strategies for developing paraben-free formulations, ranging from other authorised preservatives to combinations of organic acids and multifunctional ingredients.The appropriate alternative will always depend on the characteristics of the formulation.
How does pH influence preservatives?
pH can be a determining factor in the activity of certain preservatives. Organic acids, for example, have an effectiveness that is strongly influenced by pH.For this reason, the target pH should be considered from the early stages of development.
What is a Challenge Test in cosmetics?
A Challenge Test is a test used to evaluate the effectiveness of the antimicrobial protection of a cosmetic formulation through the controlled inoculation of specific microorganisms and subsequent monitoring of their evolution.ISO 11930 is one of the main reference standards used for this evaluation.
Cosmetic preservation solutions at LEMMEL
At LEMMEL we work with cosmetic manufacturers and formulation laboratories, supplying raw materials and technical support for the development of different cosmetic preservation systems.Our aim is to help formulators find the most appropriate solution according to the specific characteristics of each project.
We can provide support with:
- Selection of cosmetic preservatives.
- Multifunctional ingredients and preservative boosters.
- Development of paraben-free systems.
- Strategies for Clean Beauty formulations.
- Optimisation of the preservative system according to pH and formulation.
- Technical, toxicological and regulatory information on raw materials.
- Microbiological evaluation and Challenge Testing.
At LEMMEL, we have extensive experience in the distribution of raw materials for the cosmetics industry and work closely with R&D departments to identify solutions adapted to their specific requirements.
Are you developing a formulation and looking for the right preservative system? Contact our technical team and we will help you evaluate the alternatives available for your project.