Natural Preservatives for cosmetics | Luisa Fanzani
3 weeks ago

Two days ago, I received an email from a potential customer who wanted to hire me for an "intimate parts" product.

I enquired about the project budget and the client said "money is not a problem".

I was pretty excited! It seemed like a smooth project with a good margin.

We scheduled a phone call to further discuss the project. During our phone conversation, I found out that this client wished to add probiotics to the product .

"There's no way probiotics can survive in presence of the preservative".

This is what my client replied: "DON'T ADD THE PRESERVATIVE, THEN. "

There's a new horrible trend going on. It feeds itself on the (false ) belief that everything that is natural is good and vice versa. As a consequence, some brands started making "preservative free cosmetics".

According to some people, preservatives are not necessary and can be even harmful. 

It's true that a high number of skin allergies and reactions are mainly caused by preservatives and fragrances, but...this is not a valid reason to avoid using preservatives. 

What you can and should do is to inform yourself about the preservatives that are less likely to cause bad skin reactions. 

Want all natural products?

I get that.

But, even natural products should be safe and include a preservative! Just because you don't see any sign of spoilage, it doesn't mean it's not here. We know cosmetics don't have to be sterile. It would be quite ridiculous. At the same time, you don't want pathogen bacteria in them. Sure, not all bacteria, fungi, and mold are dangerous; however, even the innocuous ones could prevent the product from working the way it is supposed to do.

As brand owner, you have the legal and moral responsibility of making sure the products you sell are safe. Period.

Vitamin E is not a preservative. And no,  essential oils are not a preservative as well.

There are some studies, indeed, that prove essential oils have anti-microbial properties. Two examples are Thyme and Tea Tree oil.

Okay, so why essential oils can't be used as preservative?

"Omnia venenum sunt: nec sine veneno quicquam existit. Dosis sola facit, ut venenum non fit" (Paracelsus)

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As the wise Paracelsus figured out many years ago, the dose plays a crucial role; to exert their function as preservative, essential oils should be present as combination and at high doses (sometimes more that 3%). These high doses are extremely irritant for the skin; this is why essential oils cannot be used as preservatives. Furthermore, essential oils might be able to fight bacteria, but not fungi.

Are there products that don't require a preservative?

Yes! As a general rule, products with no water don't need a preservative; however, if you suppose they'll come in contact with water during use, then a preservative is necessary.

Oils mixtures do not require a preservative as there's no chance bacteria are going to grow in them without water. From a stability point of view, though, oils still need something able to preserve their good qualities over time...they need an antioxidant.

Fats are well known to become rancid without a good antioxidant. Vitamin E is a well known, ubiquitous antioxidant. I guess this is why it gained the wrong preservative reputation.

To summarize, vitamin E does help to preserve a product, but from a physical stability point of view only. It is not able to kill or prevent bacteria growth.

Other products that don't require a preservative are those with pH values below 4 or above 8 and products with a high content of alcohol (perfumes) or salt.

Lotions always need a preservative system. 

Natural preservatives for cosmetics

As said above, you should always add a preservative no matter if you want to keep your product 100% natural.

There are many different all natural preservatives for cosmetics. Don't listen to whoever says natural preservatives don't work very well. I've formulated many lotions with all natural preservatives and they all passed microbiological tests.

Here's a list that includes natural preservatives that work. The list is not exhaustive, so I invite you to comment with other options you have tested successfully.

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    Benzyl Alcohol. Produced by plants, it has a pleasant odor and can be found in some essential oils ,too. It is considered a safe ingredient and helps dealing with Gram+ (Staphylococcus Aerus), Gram- (such as E.Coli, and Pseudomonas Aeruginosa), fungi, and yeast. 
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    Dehydroacetic acid: a broad spectrum preservative suitable for Eco-label cosmetics. Can be used alone or in association with another preservative, for example Benzyl Alcohol. There are products that incorporate both Dehydroacetic acid and Benzyl Alcohol, for instance Geogard 221. Dehydroacetic acid has a pH dependent action; works best with pH below 6. It is also a very good anti-fungicide. Other acids effective as preservatives are sorbic and benzoic acid. 
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    Glyceryl Caprilate with activity vs bacteria and yeast. It is Ecocert/Cosmos approved and works in a wide pH range (4 to 8).
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    Potassium sorbate is a natural preservative for cosmetics and food. It can be used in a wide variety of products including makeup, skin care products, hair care products, bath products, nail polish, fragrances, oral care products, spermicides, and insect repellants. It is highly soluble in cold water.
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    Caprylhydroxamic Acid (and) Caprylyl Glycol (and) Glycerin. It's a  complete system for "preservative-free" claims cosmetics. It uses multifunctional agents that have excellent efficacy as biostatic and fungistatic agents.  It performs superbly at neutral pH and is compatible with most cosmetic ingredients. However, it can interact with residual iron found in some clay-type compounds (e.g., bentonite, silicates, etc). This interaction with iron may produce a very mild orange color or color.  It may be added to the water phase, at ambient or hot temperatures.  Lengthy exposure to elevated temperatures should be avoided. Typical use level is 0.7% w/w to 1.2% w/w.

And the winner is...

This is my favorite natural preservative (if something like favorite preservative exists 😀).

MINASOLVE GREEN B (more info here). Ecocert/Cosmos Approved. INCI: Pentylene glycol (and) Water (and) Sodium benzoate (and) Benzoic acid. Recommended use level : from 1% to 3%. Works best at pH below 6. 

Don't know where to find Minasolve or other ingredients? Insert your email below to receive a FREE guide.

Formulating with preservatives: guidelines and tips.

I don't know how familiar you are with preservative, but I am pretty sure you know that there's tons of preservatives out there. 

How to choose the right one (or the right combination)? 

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    Rule #1: pick a preservative among those in the Annex V of the EU cosmetic legislation (regularly updated). Remember, when it comes to cosmetic regulations always take Europe as a reference. The cosmetic industry is highly regulated over there and ingredients are "approved" based on their safety profile. Maximum allowable amounts for a single preservative are also listed. You can find the Annex with the list here. For example , the above mentioned Benzyl Alcohol is allowed at 1% maximum. 

When it comes to cosmetic regulations, always take EU as a reference.

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    Rule #2: Always include a preservative booster. These ingredients help the preservative to penetrate the microbes cell walls. Some of the most common preservative boosters are: glycerin, ethylhexylglycerin, butylene glycol, and pentylene glycol. If you're looking for a natural booster, I suggest Propanediol (trade name Zemea).
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    Rule #3: don't forget to add a chelator to the formula. Chelator agents such as EDTA are usually added at 0.05%. Nevertheless, they play an important role in the formulation. An amazing natural alternative is Sodium Phytate (highly water soluble as EDTA).
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    Rule #4: check your pH. Some preservatives only work within a specific pH range, so you want to make sure your product's pH falls inside the range. This information should be provided when you purchase the preservative. Remember to ask if it doesn't happen. When you have to calculate small pH intervals, strips are not the best choice. Invest some money into a pH meter. Usually if they're cheap, they're not very accurate...If you don't know what to buy, below you can see two valid options (the second one is perfect for semi-solids such as creams). Remember to calibrate the instrument before each  use, or the measure won't be accurate. For other tools to build your cosmetics lab, check this post
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    Rule #5: work following the GMPs (Good Manufacturing Practices). In the pharmaceutical world, it's common to say that "the quality of a product doesn't need to be checked, it needs to be built". Don't waste time by creating a product and checking if it's good enough afterwords (=passes stability tests). Instead, use a set of fixed principles that allow you to create a product you already know will pass stability tests. In the specific case of preservatives, do not add a lot of them to compensate for a poor lab manufacturing hygiene. Make sure you follow the GMPs and periodically check and sanitize working areas and instruments. To sanitize use alcohol or bleach. Avoid tap water and make sure your raw materials are not contaminated/expired.
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    Rule #6: always combine two or more preservatives, a.k.a use a "preservative system" to obtain a broad-spectrum protection. Remember to add an anti-fungal compound as well (for example, sorbic acid).
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    Rule #7: Perform microbiological tests! Send 2 oz of the product to a qualified lab for PET test ( Preservative Efficacy Test). During PET test the product is intentionally inoculated with bacteria to see if the preservative can withstand them.  Lastly, perform one test to make sure your product contain a limited number of bacteria AND NO pathogens (not all bacteria are pathogen). Positivity if the PET test means you need to change the preservative system. Positivity in the 2nd test means the product was already contaminated so make sure you review the production procedure and follow the GMPs.
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    Rule #8 (lotions only). Add a preservative in the water phase and the other one once the emulsion has been formed (cooling down phase). Do not add the preservative when the lotion is still hot. As said before, make sure the pH of the water phase is acid (you can use citric acid to lower the pH ).

What is your preservative of choice when making skincare? 

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