Home Cosmetic Science Talk Formulating Are these preservatives compatible with each other?

  • Are these preservatives compatible with each other?

    Posted by GeorgeBenson on May 6, 2022 at 8:01 pm

    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.

    fethtahir replied 1 year, 2 months ago 13 Members · 79 Replies
  • 79 Replies
  • Graillotion

    Member
    May 6, 2022 at 8:57 pm

    Confused…

    Is that two separate pairings….

    or

    You will use all 4 items together?

  • GeorgeBenson

    Member
    May 6, 2022 at 9:03 pm

    All four together!

  • PhilGeis

    Member
    May 6, 2022 at 9:47 pm

    Data offers no support for EHG beyond phenoxyethanol.

    What is the product?

  • GeorgeBenson

    Member
    May 6, 2022 at 11:01 pm

    Do you mean that EHG is not effective if it’s not used with phenoxyethanol?

    this is for an emulsified serum.

  • MarkBroussard

    Member
    May 7, 2022 at 1:04 am

    @GeorgeBenson

    You might try:  Sodium Benzoate (0.5%) + Potassium Sorbate (0.2%) … it often causes a flushing reaction, you’re a bit on the high side for a leave on product.  If you can use Phenoxyethanol, then Phenxoy EHG at 1%.  If you’re trying to get to a pH of 4.5, Sodium Phytate is not a good choice for a chelant since it is quite basic.  Perhaps GLDA would be a better choice if you want to formulate at relatively low pH.  If you cannot use Phenoxyethanol, Phenethyl Alcohol + Pentylene Glycol would be a good compliment.

  • GeorgeBenson

    Member
    May 7, 2022 at 1:33 am

    @MarkBroussard
    Thanks for the tips I will try that out.

    My main reason for not using phenoxyethanol in this formula is that some people may have a reaction to it, either a real physical one on their face or an emotional reaction to the word itself. But if sodium benzoate can also cause flushing than maybe i’m not any better off with that.

    Euxyl 9010 + sodium phytate is my go to preservative for pretty much everything, I’m just trying to see if I can get away with using anything else. My normal suppliers don’t seem to carry phenethyl alcohol but I’ll keep looking.

    Is GLDA compatible with cationics?

  • MarkBroussard

    Member
    May 7, 2022 at 1:48 am

    @GeorgeBenson

    The flushing reaction is more so with Potassium Sorbate than with Sodium Benzoate, although some people can be sensitive to Sodium Benzoate.  I have not had any issues with GLDA and cationics.

  • MarkBroussard

    Member
    May 7, 2022 at 2:15 am

    @GeorgeBenson

    You can source Phenethyl Alcohol from Green Line Botanicals.  To clarify what I was suggesting is:  Na Benzoate (0.5%) + Phenethyl Alcohol (0.7%) + Pentylene Glycol (2%) + GLDA (0.2%) … you could also throw in a touch of Caprylyl Glycol (0.3%) for good measure since it is an emulsified product.

  • Abdullah

    Member
    May 7, 2022 at 9:02 am

    Phenoxyethanol is milder than sodium benzoate and potassium sorbate but they target different microbes. Phenoxyethanol is for bacteria and sb&ps is for fungi.

    Also i think currently phenoxyethanol is the number one most used preservative in cosmetics. It means it is well tolerated and doesn’t have bad reputation for majority of people. 

    Why do you think it has bad reputation or people may have reaction with it? 

  • PhilGeis

    Member
    May 7, 2022 at 10:45 am

    @GeorgeBenson 
    You need to clearly state your policy.  “Very mild” is meaningless as your not looking at irritation/sensitization data.  
    You don’t like phenoxy because someone might read the label.  
    What is your policy?

  • MarkBroussard

    Member
    May 7, 2022 at 2:53 pm

    @GeorgeBenson

    Abdulla is correct.  PE9010 generally causes less irritation than Na Benzoate or Potassium Sorbate.

    But, PE9010 + Sodium Phytate as the only preservation components is weak.  A better combination would be PE9010 + Sodium Phytate + Sodium Benzoate to give you better coverage on yeast/mold/fungi.

    The reputational issue as it regards Phenoxyethanol is largely driven by retailers who are increasingly putting Phenoxyethanol on the “No” list and won’t carry products that contain Phenoxyethanol as opposed to irritation from Phenoxyethanol.  It all depends on what distrubtion channels GeorgeBenson is targeting.

  • GeorgeBenson

    Member
    May 7, 2022 at 9:46 pm

    Thank you, I will try these suggestions.

    personally I don’t have a problem with phenoxyethanol other than its smell, which is really not that bad just kinda strong sometimes, certainly not the worst as far as preservatives go (Tristat ECO is awful). But sometimes I dont want to have any fragrance at all, just letting the smell of my oils, butters, and hydrosols come through as much as possible. Plus I just want to experiment with different preservation methods. I see a lot of products preserved with some combination of sodium benzoate, potassium sorbate, glycols, etc. so I am trying that out.

  • Squinny

    Member
    May 8, 2022 at 4:15 am

    @GeorgeBenson

    Abdulla is correct.  PE9010 generally causes less irritation than Na Benzoate or Potassium Sorbate.

    But, PE9010 + Sodium Phytate as the only preservation components is weak.  A better combination would be PE9010 + Sodium Phytate + Sodium Benzoate to give you better coverage on yeast/mold/fungi.

    The reputational issue as it regards Phenoxyethanol is largely driven by retailers who are increasingly putting Phenoxyethanol on the “No” list and won’t carry products that contain Phenoxyethanol as opposed to irritation from Phenoxyethanol.  It all depends on what distrubtion channels GeorgeBenson is targeting.

    Hi Mark can you advise what % of each of  PE9010 + Sodium Phytate + Sodium Benzoate you would recommmend? Many thanks

  • Graillotion

    Member
    May 8, 2022 at 4:52 am

    I also use PE 9010 + some other things and have never had issue with yeast/mold….yet always have that nagging feeling I should add something for y/m.  If Sodium Benzoate is a possible irritant….is there another option…that just brings the y/m…but doesn’t bring any irritation to the table?  Just looking for the best possible y/m protection…without possible irritation….(and open to synthetics).  I always formulate in the range of 4.4-5.2.

  • PhilGeis

    Member
    May 8, 2022 at 9:32 am

    @Graillotion
    IPBC, Chlorphenesin. 

  • Abdullah

    Member
    May 8, 2022 at 11:33 am

    I also use PE 9010 + some other things and have never had issue with yeast/mold….yet always have that nagging feeling I should add something for y/m.  If Sodium Benzoate is a possible irritant….is there another option…that just brings the y/m…but doesn’t bring any irritation to the table?  Just looking for the best possible y/m protection…without possible irritation….(and open to synthetics).  I always formulate in the range of 4.4-5.2.

    PE 9010 os ok for shampoo but for non-ionic emulsions not trustworthy for fungi. 

    Several months ago One of my lotion samples preserved with phenoxyethanol/caprylyl glycol @9/1 ratio which is kind of similar to this one did start producing gas after a month or two of production. Mr Perry said candida contamination can be the cause. So i added 0.15% caprylhydroxamic acid to see what will happen. and there was no more gas production anymore. It is stable, no smell or color change and no more gas production up to this time. 
    Although i did not use that batch after that gas production. Just keeping it for observation purpose. 

  • GeorgeBenson

    Member
    May 8, 2022 at 12:43 pm

    @Abdullah where do you source your caprylhydroxamic acid? I’d like to try it but can’t find it anywhere, same with chlorphenesin.

  • Abdullah

    Member
    May 8, 2022 at 1:58 pm

    @Abdullah where do you source your caprylhydroxamic acid? I’d like to try it but can’t find it anywhere, same with chlorphenesin.

    I purchase most of my ingredients from china including caprylhydroxamic acid.

    I would suggest you use IPBC instead of caprylhydroxamic acid. I would also do so when i finish this batch of caprylhydroxamic acid that i have purchased.

  • MarkBroussard

    Member
    May 8, 2022 at 2:13 pm

    Squinny said:

    Hi Mark can you advise what % of each of  PE9010 + Sodium Phytate + Sodium Benzoate you would recommmend? Many thanks

    @Squinny:  For a water-based serum:  PE9010 (1%) + Sodium Benzoate (0.35%) + Pentylene Glycol (2%) + Phytic Acid (0.2%); pH = 4.6 to 4.8

    If you’re working with an emulsion:  PE9010 (1%) + Sodium Benzoate (0.35%) + Pentylene Glycol (2%) + Phytic Acid (0.2%) + Caprylyl Glycol (0.3%); pH = 4.6 to 4.8  

  • grapefruit22

    Member
    May 9, 2022 at 8:30 am

    @Abdullah where do you source your caprylhydroxamic acid? I’d like to try it but can’t find it anywhere, same with chlorphenesin.

    If you are looking for low quantity, you can find both ingredients here: https://www.myskinrecipes.com/shop/en/

  • Squinny

    Member
    May 9, 2022 at 9:36 am

    Squinny said:

    Hi Mark can you advise what % of each of  PE9010 + Sodium Phytate + Sodium Benzoate you would recommmend? Many thanks

    @Squinny:  For a water-based serum:  PE9010 (1%) + Sodium Benzoate (0.35%) + Pentylene Glycol (2%) + Phytic Acid (0.2%); pH = 4.6 to 4.8

    If you’re working with an emulsion:  PE9010 (1%) + Sodium Benzoate (0.35%) + Pentylene Glycol (2%) + Phytic Acid (0.2%) + Caprylyl Glycol (0.3%); pH = 4.6 to 4.8  

    Thanks so much for that Mark. Appreciate your advice. Cheers

  • MarkBroussard

    Member
    May 9, 2022 at 12:34 pm

    @Abdullah where do you source your caprylhydroxamic acid? I’d like to try it but can’t find it anywhere, same with chlorphenesin.

    @GeorgeBenson

    Caprylhydroxamic Acid is actually a chelating agent, not really a preservative per se.  So, you can use it in a formula as a chelator to support preservatives, but don’t rely on it as a preservative.

    Approach this like a math problem:

    Good Preservation = Bactericide + Fungicide + Chelator + Glycol/Diol Preservative Boosters + pH = 4.8  

  • grapefruit22

    Member
    May 9, 2022 at 12:43 pm

    @MarkBroussard Do you recommend a pH 4,8 only for pH-dependent preservatives, or generally for all products?

  • MarkBroussard

    Member
    May 9, 2022 at 1:07 pm

    @grapefruit22

    I would recommend using pH = 4.8 for all products where that pH is feasible.  You’re using low pH as a component of your preservation.

  • GeorgeBenson

    Member
    May 9, 2022 at 10:49 pm

    Squinny said:

    Hi Mark can you advise what % of each of  PE9010 + Sodium Phytate + Sodium Benzoate you would recommmend? Many thanks

    @Squinny:  For a water-based serum:  PE9010 (1%) + Sodium Benzoate (0.35%) + Pentylene Glycol (2%) + Phytic Acid (0.2%); pH = 4.6 to 4.8

    If you’re working with an emulsion:  PE9010 (1%) + Sodium Benzoate (0.35%) + Pentylene Glycol (2%) + Phytic Acid (0.2%) + Caprylyl Glycol (0.3%); pH = 4.6 to 4.8  

    Would your recommendations here change if the product was in an airless container?

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