A preservative is an anti-microbial solution that helps to prevent mold, yeast, and both gram- positive and gram-negative bacteria from growing in your products, without them your product can essentially be a science experiment in the making. Many people feel that placing a preservative in your product no longer makes it natural, and is adding unnecessary chemicals. While it is true that there are some chemicals that we want to stay away from, let’s remember that even essential oils are chemicals. We can pick broad-spectrum preservatives and be safe at the same time.
Hydrous=containing water Anhydrous=without water
Any formulated product that contains water will need a preservative. This encompasses any water-based product that contain hydrosols or floral waters, aloe vera, as well as any product that might come into contact with water such as consumers’ hands/fingers (consider a product like a sugar scrub, that may not contain water itself, but will likely get water into it).
*Hydrosols alone do not need a preservative, but they do not last indefinitely, store them properly in the fridge to extend their shelf life. To keep bacteria out of your hydrosols, do not touch the primary bottle with your hands or applicator; instead pour what you want into another container before doing your formulating. This will greatly reduce your risk of cross-contamination.
If you are making product at home (not to be sold), you could make it in very small batches to use as quickly as possible to avoid spoilage. Always remember, you cannot go by sight like you sometimes can in looking for spoilage in a hydrosol, so use products without preservatives at your own risk (use up in less than one week). If you are selling product, you have a responsibility for the safety of your community to add one, and to choose the safest, most appropriate one possible.
Are There Natural Preservatives?
Many say the short answer is, no (but there are a few). There are however, many misconceptions to what qualifies as a preservative. Before we get to what we can use safely, let’s cover what some are erroneously using as a preservative.
GSE (Grapefruit Seed Extract)
GSE is derived from the pulp and seeds of the grapefruit. GSE is an antioxidant containing: vitamin C, citric acid, flavonoids, phytosterols, and tocopherols…. but do not mistake it for having “appropriate” preservative properties. Here is a great link that covers why it can be misunderstood, I recommend reading the studies within (1).
GSE does have its place in formulations, but on its own, will not keep the nasties out of your product.
Vitamin E is not a preservative for hydrous product. It is an anti-oxidant that can help retard rancidity of fatty vegetable oils. It will not, however prevent microbial growth. Vitamin E would be ideal in an anhydrous product such as a body butter made with carrier oils/essential oils, as it will slow the rancidity of the carrier oil (remember they have a shelf life too).
Citric acid, like vitamin E, is an antioxidant that can help retard rancidity of fatty vegetable oils. Citric acid is tricky though as it will change the pH of your product, making it slightly more acidic (more on pH in a little bit).
Witch Hazel Hamamelis virginiana
Witch hazel is rich in antioxidants, great for most skin types, and is astringent and hydrating in nature. Witch hazel typically contains 15% alcohol (alcohol content). In order for “alcohol” to be a true preservative giving it sufficient anti-bacterial ability, you would need to use upwards of 20% pure alcohol (you can also find alcohol-free witch hazel on pharmacy shelves) (2). This may be sufficient for a room spray but would ultimately be a very costly room spray. I would not recommend using this percentage of alcohol on the skin as it will be “extremely” drying and can cause skin irritation if not mixed with a very skin nourishing base.
Rubbing alcohol, hand sanitizer, and disinfecting pads typically contain a 60–70% solution of isopropyl alcohol in water to be effective, according to the WHO (World Health Organization) (3).
Therefore, witch hazel, with a mere 15% alcohol content, mixed with water is not a proper, effective preservative.
Essential oils themselves are sometimes touted as preservatives. Let’s look at why that is not effective:
According to a study done in 2012 by frontiers in microbiology, “The main obstacle for using essential oil constituents as food preservatives is that they are most often not potent enough as single components, and they cause negative organoleptic effects when added in sufficient amounts to provide an antimicrobial effect” (4). When taking the statement of essential oils being ineffective in food preservatives into consideration, you can reasonably conclude that you would likely need to use more than would be considered safe to apply topically in order to be effective.
*It is also important to note that what is actually being used as preservatives in food such as in meats and coating for food packaging films in the food industry is actually a CO2 extract, which is extracted differently than the essential oil counterpart, and is therefore, different in it’s chemical makeup.
Do not rely on an essential oil to provide you with the preservative properties that would be necessary in a hydrous product.
A Peek At pH
What is pH? Our skin is covered in a fine film, which is called the acid mantle. This film measures anywhere from a pH of 4.7 to 5.9 (5). This measures the acidity or alkalinity of our skin, and plays a part in our cosmetics as well. As seen in the chart below, anything below 7 is acidic, and anything above 8 is alkaline.
If your skin deviates too much from this pH range, you may see an increase in scaling, a decrease in hydration due to transepidermal water loss (a measure of the amount of water that passes from inside a body to the outside via the epidermis, the skin’s topmost layer) (6), a decrease in stratum corneum protective lipids; essentially an overall inability to protect our skin.
Our skin care products should have an average pH range of 4.7 to 6 (to be as close to the pH of the acid mantle as possible). The acid mantle is an effective form of protection, but again if your pH level is consistently too alkaline or too acidic, the mantle is disturbed and skin conditions such as dermatitis, eczema, and rosacea can develop.
Let’s look at an example. Cleansers, such as bars of soap and detergent soap tend to be very alkaline in nature, and will be incredibly drying to the skin; the main reason why you have heard do not wash your face with soap, or even over wash. Therefore, using a cleanser that is slightly acidic will cleanse the skin and will not be too drying in the process.
A Brief Look At Four Preservatives
Optiphen Plus is my go to preservative for hydrous
products. Optiphen Plus works best for a product with a pH under 6.0 (acidic). It is paraben free. This preservative is effective against bacteria, yeast, mold, and fungus and is suitable for water containing products.
PROS– Paraben free for those that are sensitive. Broad-range preservative.
CONS-pH range is limited. May not be suitable for products that are more alkaline in nature (soap).
Germall Plus is my second choice. It is a broad spectrum, paraben free preservative. It is suitable for a wide pH range, so a little less guesswork in this preservative. Germall Plus is not particularly heat stable so be sure to add during the cooling down phase of your formulating.
PROS– Paraben free for those that are sensitive. Suitable for a wide pH range.
CONS– Not heat stable.
This is a preservative that is suitable for anhydrous product (not many are). Phenonip does contain parabens for those that are sensitive to them, but it is a powerful broad spectrum preservative. Like Germall Plus, it is suitable for a wide range pH range (7).
PROS– Suitable for hydrous and anhydrous product. Suitable for a wide range of pH levels.
CONS– A little challenging to work with when making lotion, have to separate during oil and water phases.
Geogard Ultra is a broad spectrum preservative. It contains no parabens or formaldehyde releasers, so it is considered “natural”. It contains gluconolactone, and sodium benzoate. This comes in a powder but can be mixed with water then added to your product in the heated water phase or cool down phase. It is however, pH sensitive to a range of 3-6 (8).
PROS– Paraben and formaldehyde free. Can add to either phase of product making (heat or cool).
CONS-Some have stated that it’s effectiveness wanes so does not provide protection much past one year. Formulating at the higher end of the dosage recommendation is likely key.
Determining The pH Of Your Product
If you own a business and make cosmetic products with intent to apply to the skin AND are using water, you need to be aware of the pH of your product. Enter litmus pH indicator test strips. You can find them easily with a Google search and can test your product, determine the pH, then use the appropriate preservative. Always follow container instructions.
Risks of Not Using a Preservative
Some have asked, what are the risks of a product containing no preservative? If we allow the microbes, yeast, and fungus to grow in our product, what are the real risks? If you have a cut on your skin, you are now incredibly vulnerable to infection by using the product topically. This can mean anything from blood poisoning, yeast infection, cellulitis, staph or MRSA. The perceived benefit of being “natural” does not outweigh the very real risks.
What Increases Rate of Spoilage?
Much like essential oils: sunlight, oxygen, heat, moisture and bacteria from your fingers can all be detrimental to your products.
Practice GMP (Good Manufacturing Practices) when making product. Be sure your hands, work surface, and utensils are clean and sterile. Boil storage containers and wear protective clothing. This includes nitrite or vinyl gloves, hair net, facemask, eye protection, and lab coat (9). This will help ensure that you do not introduce bacteria or contaminate your batch. Commercial skin care production always follows GMP practices for this same reason.
Store your products in dark, airtight containers to limit exposure to air, which increases rates of oxidation. Avoid heat. Do not dip your fingers into your product; use a clean spoon or another appropriate utensil.
The use of preservatives is essential to prevent product contamination in any product containing water. As you can now see, the perceived risk does not outweigh the benefit. Be sure to read labels before purchasing product, and if the label says “preservative free” and contains water, leave it on the shelf. If you are making product at home and have more questions, feel free to email firstname.lastname@example.org.
(1) Preservatives: Grapefruit seed extract (GSE) is NOT a preservative. Retrieved from http://swiftcraftymonkey.blogspot.com/2010/10/preservatives-grapefruit-seed-extract.html
(2) Essential Oils in Food Preservation: Mode of Action, Synergies, and Interactions with Food Matrix Components. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3265747/
(2) Preservation of Cosmetics Retrieved from http://www.makingcosmetics.com/How-to-Preserve-Cosmetics_ep_58.html
(3) Alcohol. Retrieved from http://cosmetics.specialchem.com/tech-library/article/alcohol?id=1424&or=s192994_101_1424&q=alcohol+%2bpreservative
(4) Guide to Local Production: WHO-recommended Handrub Formulations. Retrieved from http://www.who.int/gpsc/5may/Guide_to_Local_Production.pdf
(5) Understanding the Acid Mantle. Retrieved from http://thenakedchemist.com/understanding-the-acid-mantle/
(6) Everything You Wanted to Know About Transepidermal Water Loss (TEWL). Retrieved from http://blog.pharmacymix.com/everything-you-wanted-to-know-about-transepidermal-water-loss-tewl
(7) Preservatives: Liquid Germall Plus. Retrieved from http://swiftcraftymonkey.blogspot.com/2010/10/preservatives-liquid-germall-plus.html
(8) Webb, M. (2015) Aromatic Medicine, Integrated Advanced Essential Oil Therapeutics for Common Clinical Conditions (Slide 216)
(9) Webb, M. (2015) Aromatic Medicine, Integrated Advanced Essential Oil Therapeutics for Common Clinical Conditions (Slide 181)
Leslie Moldenauer, CHNC, HHP, Certified Aromatherapist, has been studying natural living and holistic wellness for over 10 years. Leslie is a trusted resource that covers essential oil safety and encompasses all that natural living has to offer. She is passionate about providing education and tools to help others make decisions regarding safety above all things when utilizing aromatherapy in the home.