After many inquiries over the past year, I figured I would write up a post about the differences between an antioxidant and a preservative. The two are not synonyms... they are different products, which do completely different things.
Antioxidants are substances that prevent or slow oxidation. What this means in the cosmetic world, is adding an antioxidant to your cosmetic formula will prevent the oils from going rancid prematurely. They are not preservatives. they cannot preserve a formula where water was added. They are generally used in anhydrous (lacking water) formulas such as balms, ointments and body butters. Examples of antioxidants include Vitamin E, Rosemary Oleoresin Extract (ROE) and Grapefruit Seed Extract (GSE).
Preservatives are substances that preserve the formula by preventing (for a reasonable time) the growth of microorganisms, or occurrence of undesirable chemical reactions (such as oxidation), that spoil it. Preservatives are very necessary to hydrous formulas as it is the water in the formula that becomes a breeding ground for bacteria. Without a preservative your product is not safe for use as bacteria will start to breed in a very short time period. Placing your formula in the fridge, will help lengthen it's shelf life, but for maybe a few hours at best. Examples of preservatives are Liquid Germall® Plus , Optiphen® , and Phenonip, to name a few.
What about Natural Preservatives?
There are a few natural preservatives out there, however they are either extremely hard to work with, not approved for cosmetic use, and/or they are extremely stinky.
GSE is said to be a preservative, but this is not the actual case. 100% GSE might have some merit, but most GSE out there is a 60/40 mix of glycerin and GSE. Some even contain synthetic preservatives that work as the preservative in the cosmetic formula, making it appear that the GSE is effective. I would personally not bet my life on GSE being an effective preservative on it's own.
Some companies have worked out wonderful natural preservative systems, and because of this edge they do have over the rest of us, they will not share their secrets to the general public (hey, would you?). Alot of people are skeptical in this regard and believe the company is outright lying. I, however, believe that if there is a will there is a way and I just have not figured it out yet.
So, truth be told, as natural as you want to be, your formula probably does need a preservative, most likely synthetic, if you add water (or any ingredient that has water in it, such as aloe vera)and want it to be safe.
I hope this clears a few questions up!