About preservative selection

Hi everyone, I want to ask about preservative selection. I was taught to always use a broad spectrum preservative in the highest recommendation rate of the supplier to get the best shelf life of the product. However with the hundreds of different preservative blends out there, how do we decide the best one?

Since I emphasize on broad spectrum, I always use combination of DMDM hydantoin 0.6% (maximum limit, and for bactericidal function) and Potassium sorbate 0.6% (for fungicidal function). Both of these comes from singular item (not a blend). I choose this because i think it is easy to work with, as it can stand heat to 80C, and potassium sorbate work effectively in pH <6.

I can see many bodywash, shampoo and wash-off product use these preservative, so I suppose it is fine in these range. But what about leave-on product?

I do not see many lotion, creams, and moisturizer use these preservatives. What I have gathered, many uses like Euxyl PE9010 (phenoxyethanol & ethylhexylglycerin), or opthiphen (phenoxyethanol, sorbic acid, caprylyl glycol). Are these milder or specially made for leave-on product?

Otherwise, what do you think of using DMDM Hydantoin and Potassium sorbate for cream, or lotion? (even for face cream). It is very cheap and accesible, but I'm worried about its safety for leave-on. 

Thanks and really looking forward to hear your experience guys :)


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Comments

  • PhilGeisPhilGeis Member, Professional formulator
    Tho DMDM hydantoi is high and I'd prefer nbezoate or IPBC over sorbate,  there's no obvious reason your combination should be not work if pH is ok..

  • @PhilGeis ; thanks for your insight. What do you mean DMDM Hydantoin is high? (Do you mean my input at 0.6% is too high?).

    I agree, my combination of DMDM Hydantoin and Potassium sorbate should work, but I just wonder whether it is safe enough to be used on leave-on product?

    Is there any valid information or research that mentioned Sodium benzoate is milder to skin compares to DMDM Hydantoin? and does it work equally effective compares to DMDM Hydantoin?

    Once again, thank you so much for your information :)


  • here in the Philippines we use DMDMH for leave on and rinse off applications (but not for oral care products) at 0.4%. some use this alone, or combines with Euxyl PE9010 and it works just fine. the reason why we use this is 

    1. stable at a wide pH range
    2. very cheap
    3. can be used for virtually any product 
  • @crisbaysauli Thank you so much! I'm glad there are people out there have tried using DMDM Hydantoin for leave-on products and its works just fine.

    Now, I can be more confident in using this preservative for my leave-on product. :)
  • PhilGeisPhilGeis Member, Professional formulator
    Yes the combination is safe enough.  A formaldehyde releaser (e.g. DMDM hydantion, Germall, Germal II) with parabens was the most common preservative system through the latter 2 decades of the last century.

    You should add EDTA.
  • Phenonip can be a good option. It's a blend of Phenoxyethanol and several parabens. Easy to work with, tolerates heating (and actually prefers it to reduce partition) works in many types of formulas (although I don't like it where transparency is important; micellar waters, serums etc).
  • @PhilGeis yes, I always try to add EDTA 0.2% on my formulation. Although it acts as chelating agent, but it is said it can help boost the preservative effect. But sometimes I don't use it where cation surfactant is in my formula. Thanks for your insight.

    @ngarayeva001 the problem in my region here, small supplier won't say the trade name. I can never source phenonip here. Instead, I can only find singular item such phenoxyethanol, which this brings me to another question guys.

    Kemidant L Plus: according to the SDS, it is broad spectrum. Its INCI: DMDM Hydantoin, Iodopropynyl butylcarbamate, butylene glycol, aqua.

    Can I think of it same as when I make my own preservative blend? In this case I buy singular item of DMDM Hydantoin (bactericidal), and Potassium Sorbate (fungicidal). Then i use both at the allowed maximum input by European commision, which is (DMDM Hydantoin 0.6%, and Potassium Sorbate 0.6%).

    With using blend of singular item (without trademark or brands), the cost will be much cheaper and easily accessible. What do you think guys?  
  • PhilGeisPhilGeis Member, Professional formulator
    I'm with you in preferring addition of individual preservatives.  Prepared mixtures lock you into ratios.  
    I assume you're not selling in Japan.
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