Preservatives: Phenoxyethanol

Phenoxyethanol is a phenolic compound with an alcohol functional group that we find in quite a few preservatives. It is not a formaldehyde releaser. It has good activity* against Gram positive and Gram negative bacteria as well as yeast, and is generally paired up with another preservative – a quaternium, benzoic acid, or parabens to...

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Preservatives: Imidiazolidinyl and diazolidinyl urea

Imidiazolidinyl urea is one of the most common preservatives, found as Germall 115 (a powder). Created through a chemical reaction of allantoin and formaldehyde in the presence of a sodium hydroxide solution, it’s then neutralized with hydrochloric acid and evaporated. It’s a good anti-bacterial preservative that isn’t great with fungus, so it is generally combined...

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Preservatives: Parabens (updated February 2021)

Yesterday we took a look at organic acids, including benzoic acid. This is the category under which parabens fall, as they are para-hydroxybenzoic acids. There are five parabens we find in cosmetic products – methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben – and two isomers – isopropylparaben and isobutylparaben – and the position of the functional...

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Preservatives: Water activity and sugar/salt scrubs

p wrote this really great comment in this post (it’s really long, so I’d encourage you to read the entire thing in the post as I’m editing it slightly for space): I’m in the minority here, leaving my sugar scrubs unpreserved…My reasoning is that any water introduced to the product will dissolve sugar until it reaches...

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Preservatives: Organic acids & sodium benzoate

One of the classes of preservatives we use in our products is the organic acids, their salts and esters. This group includes benzoic acid, carbamates (like iodopropyl butylcarbamate), and variations on salicylic acid and sorbic acid. The organic acids have moderate bacterial activity and great fungicidal activity. The acids have low water solubility, which is...

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