Alcohol as a preservative in cosmetic formulations

Hi there!

I have some experience on the development of natural cosmetics (following the guidelines of Ecocert and Natrue), but there's still SO many things that I know just a little about. One of them is preservation

So, there's this German brand called Alverde (link: https://www.dm.de/search?query=alverde NATURKOSMETIK&searchType=product&brandName=alverde NATURKOSMETIKthat we really like in the lab that I work in. I was studying the formulation of their products and I noticed that a lot of them don't have preservatives, just alcohol. Could alcohol be the sole preservative in these formulas? Does anyone has experience using alcohol as a preservative in cosmetics? I'd really like to stard this discussion :smile: 

Also, I'm always available if anyone need some help with natural cosmetics. 

Looking forward to hear from you.

Kind regards,

Comments

  • PhilGeisPhilGeis Member, Professional formulator
    ethanol at 20%
  • HerbnerdHerbnerd Member
    I'm currently developing products to Natrue standard. A number of compounds seem to influence preservation whilst not being on the approved preservative list under Annex 4 of the standard.

    If you check out various suppliers - such as this one (and there are many more) they offer a number of other 'multifunctionals' that offer antimicrobials that are based on flavour compounds and other molecules. 

    https://cosphatec.com/en/products/

    Often you will get clues to what others are using from reading the labels.




  • PhilGeisPhilGeis Member, Professional formulator
    Multifunctionals?  Those are (weak) preservatives, and multifunctional here is a head fake to the Directive.
  • PerryPerry Administrator, Professional Chemist
    You need to always be skeptical of ingredient advice from companies that are trying to sell you ingredients. That isn't to say that they are lying, but claims like "multifunctional" and "influence preservation" are vague things that don't mean anything specific.
  • Bill_TogeBill_Toge Member, Professional Chemist
    from my experience with mouthwashes, effective preservation can be achieved at lower levels of alcohol (10-15%) if the formula also contains cetyl pyridinium chloride or a similar cationic surfactant
    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
  • PhilGeisPhilGeis Member, Professional formulator
    edited June 7
    True Bill - alcohol with quats  can be effective combination.
  • PhilGeis said:
    ethanol at 20%
    Thank you for the heads up.
    I wonder that at this concentration ethanol can maybe affect the viscosity of some systems, but I think I'll have to try that out to see if it happens in my system. 
  • Herbnerd said:
    I'm currently developing products to Natrue standard. A number of compounds seem to influence preservation whilst not being on the approved preservative list under Annex 4 of the standard.

    If you check out various suppliers - such as this one (and there are many more) they offer a number of other 'multifunctionals' that offer antimicrobials that are based on flavour compounds and other molecules. 

    https://cosphatec.com/en/products/

    Often you will get clues to what others are using from reading the labels.




    Thank you!
    I discovered these Cosphatec's preservatives while I was doing some research days ago. I've found out that Alverde uses a lot of Levulinic Acid and Sodium Levulinate, which are also flavour/fragrance compounds. While I'm skeptical about these 'multifunctional' allegations, I really want to test them and see how (and if) they work. 
  • Syl said:
    Oh, great! Thank you, Syl. I'll definitely read through it.
  • Perry said:
    You need to always be skeptical of ingredient advice from companies that are trying to sell you ingredients. That isn't to say that they are lying, but claims like "multifunctional" and "influence preservation" are vague things that don't mean anything specific.
    I'm very skeptical of those claims. Nowadays every company market their preservatives as 'multifunctional' and 'broad spectrum', which I doubt that is true (in most cases). 
  • Bill_Toge said:
    from my experience with mouthwashes, effective preservation can be achieved at lower levels of alcohol (10-15%) if the formula also contains cetyl pyridinium chloride or a similar cationic surfactant
    Thank you, Bill!
    Unfortunately we can't use quats on natural formulations, since they are prohibited by certifications bodies, like Natrue and COSMOS-Standard.
  • HerbnerdHerbnerd Member
    Herbnerd said:
    I'm currently developing products to Natrue standard. A number of compounds seem to influence preservation whilst not being on the approved preservative list under Annex 4 of the standard.

    If you check out various suppliers - such as this one (and there are many more) they offer a number of other 'multifunctionals' that offer antimicrobials that are based on flavour compounds and other molecules. 

    https://cosphatec.com/en/products/

    Often you will get clues to what others are using from reading the labels.




    Thank you!
    I discovered these Cosphatec's preservatives while I was doing some research days ago. I've found out that Alverde uses a lot of Levulinic Acid and Sodium Levulinate, which are also flavour/fragrance compounds. While I'm skeptical about these 'multifunctional' allegations, I really want to test them and see how (and if) they work. 

    The toothpastes I am working on mostly do not have any preservatives added to them - the various compounds in the essential oils do the job effectively. We have tested this to BP/EP preservative efficacy testing/micro challenge and we have demonstrated that the formula works well and passes all testing.

    A couple of formulae did fail BP/EP preservative testing (only on Aspergillus brasiliensis, all other micro passed) and these used ISO 9235 compliant flavours rather than essential oils; however, based on the results, these would USP preservative testing and definitely pass ISO testing. We did decide to use potassium sorbate in these formulae. That said, we do plan to trial other compounds to see if it is possible to remove the potassium sorbate.

    I'm open to trying them. I wouldn't say I am entirely skeptical about them - but I would need to test and prove them. These compounds may not be suitable for everything - Inolex have some compounds, but have advised against their use in oral care. Symrise have offered other products including raspberry ketone. I;ve not tried the symrise products because the raspberry ketone would definitely impact the flavour
  • PhilGeisPhilGeis Member, Professional formulator
    edited June 8
    Try them - they've been around for a long time and there's a reason you see little use - they don't work well.  Watch the pH - their pKa's are around 4.5.  Please don't engage with Cosphatec's dishonest  "multifunctional" dodge.  

    Toothpaste is irrelevant to other cosmetics - formulation is generally  hostile with flavoring agents, Aw and some with benzoate or parabens.  Packaging is protective.

    USP is a poor determinant of micro safety and the others not much better.  None of these is validated to protection in consumer use - the primary purpose of preservation - and you're clearly playing at the edge of efficacy even for those.   
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