I am trying to formulate a serum using very mild preservatives. Target ph is 4.5. I am thinking about trying this combination:
sodium benzoate - 0.5%
Potassium sorbate - 0.5%
Caprylyl Glycol/EHG (makingcosmetics) - 1%
Sodium phytate - 0.2 %
are any of these incompatible with each other or redundant? Or does this preservative blend even make sense? I know only getting it tested can provide me a definite answer but before I even get to that point I want to make sure this is even a good starting point. Any feedback is appreciated.