Modern solutions in cosmetics’ preservation

Among conscious users of cosmetics’ preservatives are one of the leading topics. Controversial substances most often present in them are described in Annex V to the Cosmetics Regulation. Unfortunately, the information presented by bloggers, influencers and social media is often unreliable, misleading users and arousing unnecessary fear. Due to this, producers of raw materials try to meet the needs of a dynamically evolving industry and provide new opportunities. However, it must be taken into account that the introduction of modern solutions is a great challenge for technologists and marketers, because removing key ingredients from the recipe often leads to a large financial and time expenditure. Apart from that, creating a universal cosmetic product is impossible - users present many discrepancies in the perception of individual raw materials. Thus manufacturers try to find a compromise between "good composition", price and the necessary microbiological protection of the cosmetic.

Aversion to basic preservatives

A lot of myths have arisen around the cosmetic ingredients listed in Annex V to the Regulation No 1223/2009, however if an ingredient is approved for use in a certain concentration, it means that on the basis of current knowledge it is considered safe. Some of the banned ones include parabens, MIT + MCIT, phenoxyethanol, DMDM hydantoin, urea derivatives and many more. Fortunately, we are still able to use Potassium Sorbate and Sodium Benzoate, Dehydroacetic Acid and Ethyl Lauroyl Arginate HCl. Concerns about them stemmed mainly from their synthetic origin and occasional skin irritations. Manufacturers use the lack of these substances in the composition of the cosmetic as an element of marketing and abuse the descriptions "without parabens", "without formaldehyde donors", but in this way they discourage users from using these substances and build unsubstantiated anxiety. These declarations can only be used in specific situations where the lack of a given ingredient is a real benefit, e.g. in products for the youngest children.

New possibilities

The inhibitory effect on the multiplication of microorganisms is also exhibited by other substances outside of Annex V, and this opens the possibility of creating a cosmetic product without ingredients frowned upon by customers. A characteristic feature of new raw materials, in contrast to classic systems, is their multi-functionality. Until now, many of them were used as preservative booster, because they support the action of the main ingredient (from Annex V) and enable its concentration to be reduced. It turned out, however, that the use of the right combination of boosters is enough to provide cosmetics with effective protection without the basic preservative. Of course, there are no ideal ingredients, so when choosing alternative preservation systems, it must be pointed out that their price, due to the still low interest, is high. This significantly impacts the price of the finished product, because often even up to a few percent of the raw material has to be used to obtain proper microbiological protection. Also their additional properties can be an obstacle - usually the smell is causing issues.

The main and most popular alternatives are various alcohols and their derivatives and sugars:

• Phenethyl Alcohol

• Pentylene Glycol, 1,2-Hexylene Glycol, novelty Heptylene Glycol, Caprylyl Glycol, Decylene Glycol, Propanediol

• Ethylhexylglycerin

• Methylheptylglycerin

• Glyceryl Caprylate or Glyceryl Undecylenate

• o-Cymen-5-ol

• Phenylpropanol

• Xylitol, Anhydroxylitol, Xylityl Sesquicaprylate

• Maltol + Polyquaternium-80

There are also different, interesting and effective alternatives such as:

• Lysine

• Hydroxyacetophenone (Piceol)

• Hinokitiol

• Raspberry Ketone

• Caprylhydroxamic Acid

• Levulinic Acid and its sodium salt

• Anisic Acid and its sodium salt

• Lonicera Japonica extract

• blend of esters and aromatic alcohols with INCI name Parfum

Some manufacturers manage to protect their product by using only phenethyl alcohol, but its effectiveness depends on many factors (concentration of the substance, other ingredients in the recipe, pH, type of packaging). It is not a cheap solution, but it has its important advantages such as naturalness and a beautiful scent of violet (Phenethyl Alcohol is a component of essential oils from rose or geranium).

Glycols are increasingly common ingredients in recipes that successfully displace Glycerin and Propylene Glycol, because they have similar properties: they moisturize and soften the skin, prevent the cosmetic product from drying out, and at the same time do not cause a sticky feeling on the skin and can be a solvent for active substances with higher polarity (e.g. hydroxyacetophenone, resveratrol, some fragrances). They effectively protect against bacteria, but need other substances’ support against fungi and molds.

Ethylhexylglycerin, similarly to methylheptylglycerin, at a concentration higher than that imparting a microstatic effect, is an active substance with a moisturizing and emollient effect, reduces the bleaching of emulsions on the skin, and is also ideal for use in deodorants that will not disturb a healthy microbiome. 

Glycerides of caprylic or undecylenic acid, in addition to preservation properties and conditioning the skin and hair, have refattening and moisturizing effects, and may also support the process of emulsifying the oil phase. 

O-cymen-5-ol is an interesting and effective alternative to classic preservatives. It has a number of advantages: it works not only against bacteria and fungi, but also viruses, provides additional antioxidant protection, soothes redness and inflammation, prevents acne from deepening, which is why it works well in cosmetics tackling these kinds of issues..

Fenylpropanol is a fragrance found in strawberry fruit, hyacinth and narcissus flowers. It exhibits a wide spectrum of microbiological activity and pH, which is why it has been used in many types of formulations, in which you can additionally omit including the fragrance composition.

One of the new directions of alternatives development are Xylitol derivatives. They can protect toiletries (shampoos, gels) alone, but in emulsions they require additional support. They are perfect for deodorants and scalp products, and due to their chemical structure, they perfectly moisturize the skin.

An intriguing alternative is the composition of Maltol and Polyquaternium-80, which has a pleasant caramel smell, conditioning effect on the skin, and at a low concentration - high efficiency and natural origin.

Among the single-component alternatives there is quite a surprising raw material, namely polypsilone-lysine. It is an amino acid, so it can be a building and nourishing element for the skin, and additionally has a conditioning effect on the hair. It is very effective, but is used rather sparingly, usually in most sophisticated recipes as it is a very expensive ingredient.

A novelty on the cosmetics market is Raspberry Ketone, which at a concentration of 1% perfectly copes with the microbiological protection of the mass. It has a beautiful raspberry scent, thanks to which we do not need to use a fragrance. Additionally it scavenges free radicals, is biodegradable and stable to heat up to 80 ° C. It is also important that it does not adversely affect the natural microbiome of the skin.

Hydroxyacetophenone is a component that is not new, but has been gaining popularity recently as it works well in a system with glycols. Using it allows us to declare the lack of preservatives - both of these substances are boosters and do not appear in Annex V. Its only downside is synthetic origin, but it is worth knowing that it occurs in many different plants, including white spruce, and has antioxidant and soothing properties. It works in a wide pH range, which is especially important in cosmetic products with peptides. The working spectrum includes bacteria, molds and fungi, does not discolor the mass and does not irritate the mucous membranes.

Another interesting booster found in conifers is Hinokitiol, which has a characteristic cypress scent. An interesting fact is its proven antibacterial and antiviral effect, and even - due to the terpene structure of the molecule - anti-inflammatory.

A different alternative to classic preservatives is Caprylhydroxamic Acid, which works to protect against fungi and molds, but requires antibacterial support, which is why it is often combined with caprylic glycol. Caprylohydroxamic acid additionally has chelating properties and also moisturizes the skin.

Increasingly popular ingredients are Levulinic and Anise Acids and their sodium salts. They are very gentle to the skin, and at the same time very effective, as long as we provide them with an additional wetting agent, for example Glyceryl Caprylate. Additionally Anise Acid has a delicate scent, so it can be a perfuming element of the product. Sodium Levulinate and Sodium Anisate, thanks to their gentle manner, work well in products designed for children.

Lonicera extract is another interesting alternative - we do not show any preservatives in the composition of the cosmetic, but only an extract that is very well received by users who like a minimalist and compositions in “clean beauty” trend.

Some manufacturers use ready-made preservatives that have the INCI name: Parfum. This is an interesting procedure that allows you to hide two ingredients in the formulation under one name - preservatives and a fragrance. They usually have an interesting smell (e.g. slightly anise or mint), so they can be a stand-alone composition, but it is worth taking into account that they can distort the smell of synthetic perfumes. As a rule, they are very gentle to the skin and mucous membranes, even at a dose of up to 2.5%.

Natural preservative blends 

Chemists are constantly trying to create the perfect preservative, which is why suppliers can offer us more and more extract blends that effectively block the multiplication of microorganisms. Most often they are based on citrus extracts or oils, garlic ferment, radish ferment. Here are just a few examples of INCI composition:

• Gluconic Acid, Caprylyl/Capryl Glucoside, Cymbopogon Citratus Leaf Oil

• Pentylene Glycol, Glycerin, Citrus Aurantium Amara Fruit Extract, Citrus Reticulata Fruit Extract, Citrus Aurantium Sinensis Peel Extract

• Camellia Sinensis Leaf Extract, Yeast Ferment Extract, Glycerin, Allium Sativum Bulb Extract, Water

• Glycerin, Citrus Reticulata Fruit Extract, Citrus Aurantium Amara Fruit Extract, Citrus Sinensis Peel Extract, Ascorbic Acid, Citric Acid, Lactic Acid, Water

• Benzyl Alcohol, Glycerin, Citrus Reticulata Fruit Extract, Citrus Aurantium Amara Fruit Extract, Citrus Sinensis Peel Extract, Tocopherol, Ascorbic Acid, Citric Acid, Lactic Acid, Aqua

• Leuconostoc/ Radish Root Ferment Filtrate

Their unquestionable advantage is very high naturalness - most often 100%. In addition, they have extra properties, i.e. they support the care of the skin with seborrheic inflammation, moisturize the skin, give the product fragrance without the need of synthetic compositions.

Implementation of alternative systems into production requires financial and time investment, because alternative ingredients are much more expensive than basic preservatives. In addition, changing the preservative often causes unfortunate changes, such as thinning the mass and degrading the feeling during application, which must be corrected. Of course, a number of extra tests must also be performed: microbiological, maintenance test, stability and compatibility of the mass with the packaging. Some systems need to be enriched with additional substances, because they do not work well enough by themselves, others need to be used in high concentration, and some of the ingredients mentioned have their own characteristic smell - not always matching with the concept of the product. All these reasons make deploying and familiarizing the user with the new components a time consuming process. 

The beauty industry requires flexibility and quick adaptation to customer needs, which is reflected in the amount of cosmetic ingredients. In order to maintain high interest in the product brand, it must be constantly improved through the use of modern solutions. One of the most important of these improvements are alternative preservation systems.

Zuzanna Fedyczak dla Euro Cosmetics Magazine 7-8/2022 s.22