Hello!
I’ve used both geogard cosgard 221 INCI: (benzyl alcohol, dehydroacetic acid, aqua) and sodium benzoate and sorbate complex INCI: (aqua, sodium benzoate, potassium sorbate) deonding on ph, solubility and that kind of things. I also use natural chelator pa-3 (from Skinchakra) to boost preservative system.
First one is apparently water soluble 0,6 % but it has broader pH range, so I use it in lotions etc. Second one I use in water based, low pH projects (pH ~4-5) like toners. Oh, I usually include some sodium lactate or sodium citrate to make sure pH stays were it should.
I’ve bought these from Aroma-zone, Skinchakra or locally from Finland. I’m really happy how they work. Sometimes I combine these 2 together. Hope this helps!
Best wishes,
Johanna
