Butylene glycol + hexylene glycol to preserve water based products

I am finding a few brands use, 

BG + HG to preserve face mist, specially Korean ones. 
In some formulas they seem to use EHG. 

So basically, 
Glycols + EHG seems to be their common preservation system. 
BG+ HG + EHG for water based formulas 
BG + Capryl glycol + EHG for emulsion based formulas.
Capryl Glycol + EHG is a standard combination from Sensiva.
But Schulke doesn't give any MIC info but general use % 0.5-2%

I am breaking my head to figure out % of BG + HG + EHG for water only products.
Can anyone help!

I make water based gels and I find PE 9010 irritating in water based formulas. i think its the same with most other preservatives for water based formulas without any oils. 



  • chemicalmattchemicalmatt Member, Professional Chemist
    The formulators are reducing the water activity (Aw) using these polyols. They're using more than you think too. Check SpG of product as an indicator as these all lend density. 
  • Just a note, Korean products may contain other preservatives aside what the label lists.
    For example, it may have aloe vera extract as the first ingredient in the label, but in fact this extract consists of 1. water, 2.aloe vera extract, 3.ethanol, 4.butylene glycol, 5.phenoxyethanol, 6.chlorphenesin. All 6 ingredients under one name in the ingredient list. Though you didn't see phenoxyethanol or chlorphenesin printed on the package, but in fact they are in the formula.
  • Very good point @zetein they may not list everything. also i find their marketing a bit deceitful (few brands) like 80% hyaluronic acid serum , 50% centella extract etc.

    @chemicalmatt i understand its glycols and water activity,
    I will buy Microcount Combi to do some initial testing myself. They seem to cost me $10 per slide in my country, bit pricy but will have reduce irritation potential of my water based gels.

    Pentylene glycol seems to have good efficacy against gram+ve, -ve and yeast. 
    While hexylene glycol has good gram -ve, yeast but average with gram +ve and mold. 

    Will start testing with 4% Pentylene glycol
    If not sufficient will add Phenoxyethanol or acids.
  • Bill_TogeBill_Toge Member, Professional Chemist
    linear 1,2-glycols are antimicrobial - the efficacy increases as the chain length increases, so caprylyl glycol (C8) works better than 1,2-hexanediol (C6; 'hexylene glycol' is a branched 3,5-diol), which works better than butylene glycol (C4)
    unless they're included at 30% +, they'll not have a significant effect on the water activity
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
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