Preservatives

One of the most confusing and misunderstood topics when it comes to making cosmetics and other homemade products, knowing how and when to use preservatives is an important part of making things yourself.

Preservatives….to use them or not is often a difficult choice that soap makers and makers of bath and body products face.

On the one hand, most who venture into this craft, do so because of a desire to create something more natural and skin friendly than what is currently available commercially.

This means doing away with chemicals as much as possible.

On the other hand, doing away will all those chemicals can lead to the growth of mould and germs.

We all know that mould and germs applied directly to the skin is not exactly a skin friendly alternative.

Finding a happy medium can be a challenge but, with a little research, you’ll be able find the balance that works for you.

Why use a preservative?

Toxic ingredients aren’t the only danger that can be lurking in our cosmetics.

Microbes can also form there, whether those cosmetics are homemade or not!

The main microbes that we need to worry about when making our own products are bacteria, yeasts, and fungi such as mold. Mold is normally quite obvious to see, making it easy to tell when you should toss a certain product affected by mold growth.

Preservatives are an important part of DIY bath and body products. They help prevent mold and bacteria growth, which extends the shelf life of products and makes them safe to use.

Preservatives are recommended for products made with water or products that may get water splashed in during use. This post has information on whether they’re needed for soap, lotion, and more. Keep in mind these are general rules and may be different based on your preference, how the product will be used, whether you’re selling the product, etc. It’s a great place to start and adjust from there.

Bacterial growth can be invisible

On the other hand, bacteria can form and proliferate without us being able to see them. A normal looking drop of water can have thousands (millions?) of bacteria.

While not all bacteria are harmful, some of the bacteria that can form in our homemade cosmetics can cause infections and can make our skin break out. Bacterial infections can cause folliculitis, which many people could wrongly attribute to acne or allergic reactions.

It can even become more serious than that, though. The bacteria that form in our cosmetics could make us deathly ill.

You want to take special care when making cosmetics that will be used around the eyes or any other sensitive areas. Bacteria in eye care products can cause eye infections or even blindness! (That’s why it’s always a good idea to change out your mascara or liquid eyeliners often, even if you haven’t used them all up!)

When do you need to use a preservative?

This may be the most important question!

There is a lot of confusion about when and why to use preservatives. Not all homemade products necessarily need preservatives. In fact, in some cases, it isn’t effective to use your normal preservatives.

Water-based ingredients

Any time you add water-based ingredients to a recipe, the resulting product will be more prone to microbial growth.

Generally, water-based products or any product with water-based ingredients in it will need a preservative of some type.

This is especially true of emulsions in which you are blending together oil-based ingredients with water-based ingredients or mixtures of mostly water-based ingredients.

When does a water-based product NOT need a preservative?

There are, however, a few exceptions to the “Water-based products need a preservative rule.”

Soaps and liquid soaps

What preservatives to use in liquid soaps. While this is a bit of a controversial topic, here are some thoughts…

True soaps and liquid soaps (those soaps made with lye) are usually self-preserving. They do NOT normally need a preservative, making them exceptions to the water rule.

It is unusual for pathogenic bacteria (the kind that can do us harm) to grow in liquid soaps because they naturally have a very high pH (generally 9-10 or higher).

Any time you have a product with an extreme pH, it becomes an environment that is less hospitable to most microbes. Yes, there are some acid-loving or alkaline-loving bacteria and other microbes that exist, but they aren’t commonly a problem with homemade cosmetics and other products. Normally, you can keep a liquid soap safely diluted for up to a year without any problems.

Bar soaps and undiluted liquid soap pastes can be kept for even longer and they will usually start to smell off or go rancid before there is any worry of problems due to bacterial growth or mold.

Syndet bars or homemade shampoos and shower gels are not true soap. Their pH tends to fall in a more neutral range so they will need a preservative if water is one of their ingredients.

Preservatives for liquid soap

The problem with trying to preserve liquid soap is that most of the preservatives on the market are ineffective at the high pH of soap. There are very few exceptions.

If you are set on using a preservative for your liquid soap, these are my recommendations:

Add the preservative at the time of dilution. The soap paste itself has a very low liquid content and keeps very well.
Use a preservative whose effective pH range includes the pH of your homemade soap.
From my research, this preservative seems to be the best bet for liquid soap (and appears to be safe and paraben-free)…

Suttocide™ A (INCI: Sodium Hydroxymethylglycinate): A synthetic broad-spectrum preservative derived from Glycine with a pH of 10-12. It’s active in a pH range of 3.5-12.

I’ve seen Germall Plus and Glydant plus recommended for use in liquid soaps, but their recommended effective pH range is lower than that of most liquid soaps. Glydant Plus looks a bit more promising, but the pH range cited for Germall Plus is only 3-8.

Glydant Plus (INCI: DMDM Hydantoin & Iodopropynyl Butylcarbamate (IPBC)): A broad-spectrum preservative that is effective in a pH range of 3-9. As some soap has a higher pH, it’s debatable if this preservative would actually be helpful for use in most liquid soaps.

Do anhydrous products need a preservative?

What is an anhydrous product?

Anhydrous products are those that do NOT include water (or water-based ingredients). They are oil-based products that include liquid oils, solid oils, butters, and waxes.

Generally, oil-based products like homemade body butters or homemade lotion bars don’t need preservatives. Without the addition of water, they just aren’t prone to microbial growth.

There are exceptions, though, and cases where you will want to consider using a preservative in an oil-based product.

Anhydrous products and humidity

Just because a product doesn’t have water as one of the ingredients, doesn’t mean that water won’t eventually be incorporated into it.

Oil-based products meant to be used in the shower are especially likely to be “contaminated” with water or humidity. That’s why I recommended that you use a preservative when making an emulsified sugar scrub.

Sugar scrubs don’t normally have water as one of the ingredients. They are, however, normally used in the shower. People take their wet hands and scoop out some of the product and rub it all over their wet arms and legs. They then reach back in and scoop out some more.

Even if you were to carefully scoop out the product with a clean spoon each time, the likelihood of water or humidity getting into the container is quite high. Moisture that condenses on top of the product can form mold or can be the perfect medium for other microbial growth.

What is a “Natural” preservative?

There are many ways to define what a “natural preservative” is, so I’ll give you my definition.

Natural preservatives are those that can be used in products with a “natural” or “organic” certification because they use ECOcert certified ingredients. (There are other similar certifications, but for the sake of keeping things simple, I chose one and stuck with it.)

These preservatives have been developed to replace parabens and preservatives with formaldehyde or other ingredients that many people, looking for safer alternatives, want to avoid in their cosmetics.

In an effort to use more natural ingredients, though, some people look to natural ingredients that aren’t protecting us adequately.

When talking about preservatives, we need to use broad-spectrum preservatives, those that will inhibit the growth of a variety of unwanted bacteria and molds.

Common Natural Preservatives.

Grapefruit Seed Extract – a natural broad spectrum preservative used to kill or inhibit the growth of bacteria, viruses, fungi and other nasties. It is not, in itself, a full spectrum preservative and must be used in conjunction with other broad spectrum preservatives to be effective. Note that it can be sensitizing to some individuals. When added to a soap formula, it will speed up trace considerably.

Rosemary Extract – an anti-oxidant that slows down oxidation of natural materials. Oil based recipes containing oils that have short shelf lives can benefit from this product. Be aware that rosemary extract smells like rosemary and may add scent to your final product. Luckily, a little goes a long way.

Vitamin E Oil – another anti-oxidant. Usually a mix of tocopherols blended in an oil. Try to purchase one with at lease 50% mixed tocopherols for better protection. For use in anhydrous products.

Germaben II – is effective at preserving water and non-water based products.  Consists of Propylene Glycol, Diazolidinyl Urea, Methylparaben, Propylparaben.

Germall Plus – a broad spectrum anti-microbial preservative.  For use in anhydrous and water based products. Consists of Propylene Glycol, Diazolidinyl Urea, Iodopropynyl Butylcarbamate

Optiphen Plus – a world wide approved paraben and urea free broad spectrum preservative that is effective against bacteria, yeast and moulds. Optiphen Plus also imparts emolliency to finished products making it a great addition to lotions and cream rinses.  Consists of Phenoxyethanol, Caprylyl Glycol, Sorbic Acid.

Common natural broad-spectrum preservatives” preservative?

Alcohol

While it may not be the ideal preservative for using in lotions or shampoos, having a high enough concentration of alcohol will prevent microbial growth in homemade formulations. It also has the added advantage of being able to solubilize essential oils.

The fact that it can both solubilize and preserve makes alcohol the ideal choice for incorporating essential oils into water in products like linen sprays.

Alcohol is also great for making tinctures. By infusing plant material into the alcohol, it helps extract many of the plant’s beneficial properties.

  • For solubilizing, you want to use a strong alcohol; as near to 100% alcohol content as possible. As the percentage goes down, the amount of solubilization will also decrease. (You’ll want a minimum of 75%.)
  • For preserving and extracting, you’ll want to use an alcohol with at least a 40% alcohol content. Generally, tinctures and extracts like homemade vanilla extract or homemade bitters will use an alcohol with an alcohol content of at least 40%.
  • A good goal for making safely preserved homemade sprays is to have around 20-30% of the final formula be alcohol. That means that if you are using an alcohol with 95% alcohol content, formulate the recipe so that around 1/4th of the mixture will be that alcohol. If you are using an alcohol with a lower alcohol content, you can increase the amount used accordingly.

Glycerin

As with tinctures made with alcohol, glycerin can be used to extract the flavors, aromas, and/or the beneficial properties of certain plants and preserve them. These extractions are called glycerites.

In most cases, you won’t want to preserve a homemade product with glycerin as glycerin needs to be used in very high percentages to effectively preserve it. Also, glycerin, while a great humectant, tends to make a product feel sticky at concentrations over 5%.

To preserve with glycerin, you’ll want to use a concentration of at least 55%

Quick Guide to Products and Preservatives.

Cold process and melt and pour soap

Preservative: No

You never have to worry about adding a preservative to cold process or melt and pour. They have a pH level of 9-10, which doesn’t allow mold or bacteria to grow. Just another reason to love handmade soap.

Liquid soap

Preservative: Optional
Amount 0.5-1% of the total weight
Type: Optiphen ND

Like bar soap, liquid soap has a pH level that doesn’t allow mold to grow. However, it does require distilled water for dilution. You can add a preservative to be extra careful or if you plan to sell it.

Lotion

Preservative: Yes
Amount: 1% of the total weight
Type: Optiphen, Phenonip, or Germaben II

Lotion always needs a preservative because it’s made with water. Without one, the shelf life will only be a few weeks.

Body butter

Preservative: No

This is a simple mixture of butter and oil. Because there’s no water and it will likely be applied to dry skin, don’t worry about a preservative. As always, you can add one if you plan to sell it.

Scrubs and bath salts

Preservative: Optional
Amount: 1% of the total weight
Type: Optiphen or Phenonip

While most scrubs and bath salts aren’t made with water, they are usually stored in the shower and can get water splashed in during use. We recommend a preservative for that reason. You can skip it if the recipe is for personal use and stored in a cool, dry area in between uses.

Bath bombs

Preservative: No

Bath bombs don’t contain water so they don’t need a preservative. When choosing witch hazel to wet them, make sure it’s alcohol based or already has a preservative.

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