parabens or formaldehyde releasers, and it depends upon sodium benzoate - an organic acid - as the main preservative. It comes in a white powder format and the INCI is D-Glucono-1,5-lactone (aka gluconolactone, 70% to 80%) and sodium benzoate (22% to 28%).
We know sodium benzoate is bacteriostatic, which means it limits the growth of bacteria by messing with its metabolism and it's a fungicide. The gluconolactone is added to be a chelating and sequestering ingredient (like EDTA), a free radical scavenger, and a moisturizer that is on par with about 2% glycerin. It might also be good as an AHA substitute! The concept behind this preservative is called "hurdle technology" (look for more about this in an hour or so).
It's water soluble, so it's suitable for products that don't contain oil, and it can be used in the heated water phase or at the cool down phase, although you have to "make a solution" to include it at the end (it's a powder and needs to be dissolved). It's soluble in water, propylene glycol, glycerin, and mineral oil, and insoluble in vegetable oils, ethanol, and dimethicone. Use it at 0.75% to 2% in products with a pH of 3 to 7.
Usage of Geogard Ultra:
INCI: D-Glucono-1,5,-lactone and sodium benzoate.
Usage: 0.75% to 2% in water containing products. Not suitable for anhydrous products.
Add to any phase of your product.
Suggested pH level is 3 to 7.
Just in case you're not a regular reader of the comments, please take note of what melian has to say!
swift, some time ago tildy of southern soapers posted this information about geogard ultra:
"Be sure to use it at the higher usage levels. I had it in testing for 18 mos and not only does it have a narrower pH range than Lonza states, but long term, it is not robust... especially for any products you will be sticking your hands in repeatedly. I also checked with a few of the contract manufacturers I do business with, and they concurred with my testing results also.
Just make sure that whatever your technical data sheet actually says on the pH range that you reduce that range by 1/2 of a pH level on both upper and lower limits.
If you use it, plan to do microbiology on a 1 to 3 month interval for about 12 to 18 prior to selling. My batches for serums, lotions, and body creams saw preservative failure in the 9 mos to 18 mos time ranges.
Southern Soapers started to bring this in. We were certified and inspected to carry it, had pails ordered and paid for. That is when our final tests came back.. and we then decided NOT to bring this in."
To interpret this, so you'd want to use it at pH 3.5 to 6.5, and you want to get your products tested if you are serious about this preservative.