We add preservatives to prevent bacteria, molds, fungi, or yeast from growing in our products. You don’t want to spend all of your precious ingredients and time on making a beautiful hair mask just to find it grow all kinds of nasty things a few weeks later.
If you’re a beginner all the conflicting information about preservatives may confuse you and provoke so many questions. When I just started out my journey in the wild world of DIY bath and beauty the area of preservative was vague to me and I was surrounded by fearmonger and misinformation. I remember making my first cream and “preserving” it with Rosemary Extract. It suffices to say my beautiful product packed with skin-loving oils, butters, and plant extracts got spoiled quickly and I was very disappointed
So please, do your research about preservatives and make sure you choose the right one for your product.
What is NOT a preservative?
Antioxidants (Vitamin E, Rosemary Extract)
Grapefruit seed extract
What products need a preservative?
Products that include water, hydrosols, aloe vera juice, floral water, etc (toners, liquid shampoos, and shower gels, lotions, creams, emulsified body butters, hair conditioners, hair masks, and more or may come into contact with water like shampoo bars, conditioner bars, scrubs, cleansing bars.
What products do not need a preservative?
*If your formulation is anhydrous (doesn’t contain water) and is not going to come in contact with water then you don’t have to use a preservative (anhydrous facial serums, anhydrous body butters, lotion bars, lip scrubs, lip balms, anhydrous salves, etc). Keep them dry you’re going to be on the safe side.
*If the PH of your product is very high (9-10 or higher) then your product is self-preserving (like soap made with lye)
*If the PH of your product is lower than 4 then your product is self-preserving
*If your product contains at least 70% glycerin then it’s self-preserving
*If your product contains at least 20-25% ethanol then it’s also self-preserving
How to choose the right preservative for a certain formulation?
I am afraid, there’s no simple answer to this question. The preservative choice is going to depend on many different factors such as:
– anhydrous or hydrous product
– leave-on or rinse-off product
– your country’s safety regulations (e.g Liquid Germall Plus is not allowed for leave-on products in the EU)
– what is the PH of your final product (many preservatives are active in a certain PH range, for example, Optiphen Plus performs best in slightly acidic formulations (PH 6 or below)).
– heat-sensitivity (do you have to add your preservative to a hot product or can you wait and add to a cool-down phase?)
– hard-to preserve ingredients (botanical extracts, hydrosols, floral waters, clays, etc)
– naturally-complied formulation
I like to use Liquid Germall Plus in my rinse-off water-based products.
Euxyl PE9010 in my rinse-off and leave-on products. This preservative can be inactivated by certain ingredients (like sodium lactate, the high load of surfactants, water-soluble esters like Olivem 300, water-soluble shea, polysorbates, PEG-hydronated castor oil, etc) and it has to be mixed with glycerine or propanediol 1.3, or propylene glycol or sorbitol because it’s water solubility is limited. I use Optiphen or Euxyl PE9010 in my oil-based products.
I’ve heard that Phenonip and Germaben II are both very reliable broad-spectrum preservatives even for hard-to-preserve formulations.
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Also, each preservative has a recommended usage rate, make sure to read all the instructions about using your preservative. Most of the suppliers will include data sheets and other documentation on their ingredients so definitely give it a read before purchasing something you may not even use later.
Here’s a very good and informative article on preservatives and their usage rates from Makingcosmetics.
How to Prevent Contamination in Cosmetic Products from Chemists Corner.
What is the best preservative to use?– from Chemists Corner