Preservatives in cosmetics
The topic of preservatives has become a very sensitive topic in natural cosmetics, especially because of certain myths that place preservatives in the position of undesirable substances. We have decided to address this issue and convince you that preserving is not bad, but necessary for your safety and health.
In the article you will learn:
- what is a preservative?
- what products need to be preserved?
- how to choose the right preservative?
- an overview of natural and synthetic preservatives
Preservatives are substances that prevent the growth of bacteria (gram+ and gram-), yeasts, fungi and moulds by disruptingthe cells and spores where they germinate, thus preventing their growth, thus extending the life of your product, on average by 2 to 3 months.
They are an essential part of products that contain water, not only pure water, but also water-based raw materials such as hydrolates or aloe vera gel. However, it should be borne in mind that, in fact, most purely natural products are more susceptible to the formation of micro-organisms.
Fact or myth?
You may have heard opinions like:
My product cannot be contaminated because I work in hygienic conditions where everything is clean.
We'll disappoint you, it's a myth.
Here are some of the most important factors that make your natural product a literal paradise for microorganisms:
- high water content
- the humidity of the environment in which the product is stored or used - a humid and warm bathroom environment is ideal for bacterial growth
- the content of hydrolates, plant extracts or dried plants in the product
- the content of clays or natural gums in the product
- the storage temperature and the temperature at which the product is applied
- a pH value of approximately 4,5 to 6,5 (in fact, bacteria can thrive between pH 4 and 9, yeasts and moulds between 3 and 9)
Is it necessary to preserve anhydrous products?
Not all. For example, soap made by the cold process where a sodium hydroxide solution has been used does not require a preservative.
However, if you have a waterless product that receives ambient water, it is recommended to preserve such a product.
CAUTION! Do not be fooled by the oil base of your product. If you use an oil-soluble preservative, the preservative will remain in the oils and will not move and act where the water is, making its use unnecessary. It is therefore necessary to use a water-based preservative and to ensure that it is mixed with the oil phase by adding an emulsifier.
Think of your health
The very fact that you have chosen to produce your own natural cosmetics says that you are concerned about your health as a priority. Therefore, do not underestimate the possibility of bacteria, which can cause unpleasant health problems if your immunity is lowered or your skin is damaged. Although they are not visible to the naked eye, they are present in your product in reasonable quantities and are not visible to the naked eye even in the early stages of overgrowth.
We would also like to draw attention to the excessive application of preservatives in your products. It is not a case of the more the better, the longer your product will last. Preservatives should be used at a minimum level, from 0.5 to 4%. Remember that as they destroy bacteria, they can also destroy your skin in high proportions. Therefore, always follow the recommended dosage.
One of the main questions you will definitely ask yourself if you decide to try a preservative will be
How do you choose the right preservative for your product?
Here are a few points that should help you choose the most suitable preservative.
1 Learn to read the product information correctly
There are many preservatives on offer today. You can choose natural or synthetic. Sometimes the name of the preservative itself is quite confusing, often it is the trade name of the product or just an abbreviation. It is therefore important to be able to read the product information: the INCI, which should contain all the ingredients of the product, and you can already check these. For example, such Cosgard has an INCI: Dehydroacetic Acid & Benzyl Alcohol, which is a mixture of organic compounds of dehydroacetic acid and benzyl alcohol (on our website, every raw material has an INCI listed).
It is also interesting to know if the product is approved for use in natural cosmetics by certification companies such as COSMOS, Ecocert, Natrue or Soil Association.
2 Suitability based on the nature of your product
The nature of your product plays an important role, so you need to have defined what your product is. Here are some basic questions:
- is it a water-based product, such as a tonic?
- is it a W/O or O/W emulsion? (for more on the differences between W/O and O/W emulsions, see our article O/W or W/O?)
- is it a product that is rinsed off or left on the skin after application?
- is the product applied to the hair, the skin around the eyes, the face, the whole body or is it a baby cosmetic?
3 The pH value of the product
Another important point is the pH. It is very essential to understand that most natural preservatives are weak acids (such as salicylic acid, benzoic acid, sorbic acid, etc). They are all poorly soluble in water as acids, which is why most are supplied as sodium or potassium salts, such as sodium benzoate. But they are only effective in acid form.
What does this mean for you?
That you will need a sodium or potassium salt to introduce them into a product, but an acidic form will be needed to make them effective.
So why consistently measure the pH of the product?
Because pH greatly affects the effectiveness and solubility of a preservative.
If the pH is low, the preservative will begin to sediment in the product and can cause the product to destabilize.
If, on the other hand, the pH is high, the preservative loses its effectiveness.
Therefore, check at what pH the preservative is effective.
(Note: recall that bacteria can thrive between pH 4 and 9, yeasts and moulds between 3 and 9, which includes skin pH 4.0 - 6.5).
4 Preservatives in your product ingredients
This is a very important thing! Before you choose a preservative, you need to take into account the fact that some of the ingredients in your formulation may alreadymay already contain a preservative (for example, hydrolates are often preserved with sodium benzoate). Therefore, first and foremost, you need to choose a preservative that is compatible with the preservatives in the raw materials and also calculate how much preservativeyou can use so that you do not exceed the correct level and 'overdose' your final product. The application rates of individual preservatives range from 0.8% to 4.0%. Therefore, count accurately ;-)
5 Preservative potency range
When choosing the right preservative, it is equally important to check which contaminants the preservative is effective against. Gram positive, gram negative bacteria, yeasts and moulds are most commonly found in cosmetic products.
Therefore, if you have a preservative at home that does not cover this entire range of contaminants, you need to supplement its effectiveness with a complementary preservative.
6 Effect of the preservative on the nature of the final product
yes, this can happen, especially with natural preservatives, which are an extract from nature and hence most have their own fragrance and colour. Don't be put off though, their use is limited to a maximum of 4% and unless you want your product to be completely odourless and odourless, you won't smell the preservative in it.
In the case of emulsions, any unwanted changes in viscosity should be monitored.
But again, it's just a case of practical testing and finding the best one for your product.
It is also important to check that the preservative is not sensitive to, for example, light, which causes it to oxidise. Therefore, consider this aspect of the matter and choose the right packaging for your canned product.
As more and more natural cosmetics manufacturers are beginning to appear in our circles who do not produce only for their own needs, the above list is dedicated to them.
In your own home, it will be enough for you to start by choosing a preservative that is especially effective on the type of bacteria you need to prevent from multiplying and using the right ratio of preservative in your product.
Overview of preservatives
In our range you will find both natural and synthetic preservatives.
In this case, it is not so much the origin of the raw material that is important, but rather that you use a preservative that is effective on the range of microorganisms you need to prevent from multiplying.
If you are a cosmetics manufacturer, you will have already established this information and know exactly which preservative is best for your products. In this case, we recommend that you also have a microbiological test carried out in a laboratory, as this is the only guaranteed way to check whether the preservative you have chosen is effective.
However, if you produce at home for your own purposes, you don't have to worry about finding out. Simply choose the preservative with the widest range of effectiveness. As long as you produce reasonable quantities that you can use within a few months, the preservative will effectively protect your product from the overgrowth of unwanted micro-organisms for that period of time.
INCI: Citrus grandis (Grapefruit) Seed Extract
This is a natural product that acts as a natural antibacterial, antiparasiticit is a natural antiparasitic, antifungal and antiviral inhibitor in soaps, lotions and other cosmetic products.
It is soluble in water, alcohol and organic solvents.
The most effective range is at pH 1,5 - 3,0.
Use and application.
Scent: mild citrus
Colour: light yellow
INCI: Dehydroacetic Acid & Benzyl alcohol
Cosgard is a natural preservative that meets Ecocert and COSMOS, NaTrue Certified and Soil Association standards - dehydroacetic acid and benzyl alcohol are organic compounds that are accepted for use in natural cosmetics.
It is oil soluble, its effectiveness is at pH 2 - 7, being most effective below pH 5.5.
efficacy: broad spectrum, highly effective against gram+ bacteria, partially against gram- bacteria and moulds
Dosage: 0.5-1.15%
Its use is very wide. It can be used in the following products:
shampoos, conditioners, facial and liquid soaps, shower gels, lotions for sensitive skin, baby wipes and cloths, moisturisers, creams, baby shampoos, hair products, bubble baths, sunscreens.
Fragrance: it is almost odourless, so it lets the added fragrances of the product stand out
Colour: a slight yellow tinge which is subtly visible in transparent eau de toilette, in other cosmetics it does not affect the colour of the final product.
INCI: Glycerin, Aqua, Sodium Levulinate, Sodium Anisate
Dermosoft 1388 is a blend of organic acids derived from plants with broad antimicrobial activity, certified by Ecocert. It is therefore a natural preservative.
It is water soluble, effective at pH 5.0-5.5.
efficacy: against bacteria (both gram+ and gram-) and moulds
Dosage: 3.0-4.0%
Use: water-based products, from gels to emulsions (if the product is oil-based, it is necessary to use a solubilizer)
TIP: You can increase its activity by using 0.1% of the natural chelating agent PA-3.
To increase the effectiveness against yeasts, we recommend combining with GMCY.
Colour: colourless to pale yellow
INCI: Glyceryl caprylate
GMCY is a pure natural product - it is an ester of glycerine with caprylic acid, certified by Ecocert. In addition to being a preservative, it is also used as an emulsifier and emollient.
It is soluble in oils and alcohols and effective at pH 4.5 - 7.0 ( in the case of the aqueous phase, it is incorporated by the use of a solubilizer).
efficacy: against bacteria (gram+ and gram-)
Dosage: 0,3-0,5%
Combines very well with Dermosoft 1388 to achieve a greater spectrum of efficacy.
Colour: white (it is solid, melts at 30-35 ̊C)
INCI: Parfum
Naticide is a natural preservative. Interestingly, it is actually a fragrance (a blend of vanilla and almond), so after use it is possible to state that your product is preservative free as it is not classified as a traditional preservative.
It is soluble in oils and alcohol, in water only up to 0.6% (therefore the remaining 0.4% must be added in the cooling phase), its effectiveness is at pH 4 - 9 .
efficacy: effective against gram+ and gram- bacteria, yeasts and moulds
Dosage: 0.3-1%
Use: skin tonics (oil and dry), creams and face masks, shampoos, antiperspirants, body lotions and gels
Colour: slightly yellow tint
INCI: Triethyl Citrate, Glyceryl Caprylate, Benzoic Acid
This is a preservative approved by Ecocert, COSMOS and Natrue.
It is not water soluble, therefore a solubilizer is required for incorporation into the formulation.
It works on a water base. Its effectiveness is at pH 4.6 - 6.0.
efficacy: effective against gram+ and gram- bacteria and yeasts (for emulsions and water-based products it is sufficientfor shampoos, soaps and products based on tensides it is necessary to supplement its effects with an additional preservative).
Dosage: 1,0-1,5%
Use: tonics, gels, emulsions, deodorants, hair conditioners
TIP: Versatil TBG can be combined with Dermosoft 1388 for better effectiveness.
Colour: colourless
INCI: Phenoxyethanol & Ethylhexylglycerin
Euxyl is a synthetic broad spectrum preservative, effective against gram+, gram- bacteria, yeasts and moulds. It does not contain parabens or formaldehyde.
It has limited solubility in water (1% at 20°C) but is readily soluble in polar solvents such as propylene glycol and propandiol 1,3. It is slightly soluble in glycerol and sorbitol. Its effectiveness is up to pH 12.
Dosage: 0,5 - 1,0%
Use: creams, lotions and serums, wet wipes, shampoos, conditioners, body cosmetics
Colour: light yellow
We believe we have provided you with a sufficient information base in our posts and we keep our fingers crossed in testing our preservatives.
The article has been prepared for you by
Martina Oboňová
Sources:
https://www.schoolofnaturalskincare.com/natural-preservatives-for-cosmetics/
http://makingskincare.com/preservatives/
https://formulabotanica.com/checklist-natural-preservative-skincare/
https://www.fromnaturewithlove.com/library/preservatives.asp
