@MarkBroussard thanks I currently use 0.9% phenoxyethanol +0.1% caprylyl Glycol +0.2% EDTA in shampoo. The only problem is that it reduces the viscosity. What percentage of active DMDM hydantoin in combination with what preservative do you recommend?
I have phenoxyethanol, caprylyl Glycol, glyceryl Caprylate, caprylhydroxamic acid and Piroctone Olamine.
I don’t use DMDM, so I can’t advise you there. Given your list, I assume you’re making a Shampoo … you might try Phenoxyethanol + Caprylhydroxamic Acid … I don’t think that combination would reduce the viscosity of your shampoo.
Methyl - 0.2%. In theory, Gram negatives are the risk for shampoos so DMDM Hydantoin alone with EDTA would seem to be enough. In practice, combination with another increases protection vs. Gram negative adaptation and is a much better system.
Yes, when I first started we used a combination of DMDM Hydantoin and Methylparaben in our shampoos. It was a cost savings project that demonstrated we didn’t need the methylparaben based on our manufacturing conditions.