Home Cosmetic Science Talk Formulating Natural Ingredient expiration & Product Shelf-life

  • Natural Ingredient expiration & Product Shelf-life

    Posted by Anca_Formulator on July 16, 2022 at 9:26 pm

    Hi,

    I was taught that the shelf-life of your product depends (among other stability factors of course) on the ingredient with the shortest shelf life. This is of course a problem, since most natural raw materials have about 1 year shelf-life…

    I recently listened to a webinar on stability with Richard Lawrence (courtesy of @Perry), and he said that an ingredient can be used up to its expiration date, so even if it’s put in a product the day before it expires, the product can still be given a shelf life of 2 years for example. This is of course great news, it saves a lot of money and hassle in having to constantly purchase new lots of my raw materials. 

    Which is true though? 

    Thank you!

    anah replied 4 months, 2 weeks ago 7 Members · 15 Replies
  • 15 Replies
  • Farah

    Member
    July 17, 2022 at 8:31 am

    I’m curious to hear the answer too. Did he mean oils as well? Do they oxidize slower when they are in an emulsion? 

  • OldPerry

    Member
    July 17, 2022 at 12:45 pm

    You have to understand what it means for an ingredient to “expire”. First, read this https://chemistscorner.com/if-oils-expire-soon-will-my-cream-also-expire/

    The expiration date is not a moment when the entire sample goes bad. It’s not like a day before an ingredient was good and then the day after expiration date it goes bad. Cosmetic ingredients are not like food. (Although that’s not even true with food)

    On some level, expiration dates are arbitrary dates put on by the suppliers to give you a reasonable guess for how long an ingredient will keep working and not cause any stability problems. They also like to make the date short enough so you’ll buy more of the  ingredient. Suppliers only make money when you buy more. 

    Since most natural extracts don’t really have a noticeable impact on a formula, unless there is microbial contamination, color or odor change, you can probably ignore the expiration date and use them for as long as you like.

    Cosmetic ingredient expiration dates

  • MarkBroussard

    Member
    July 17, 2022 at 1:41 pm

    Yes, the expiration dates are made up.  Similar to expiration dates on food products … those dates represent “peak freshness” and mean that after that date the food product will begin the process of spoiling.

    The explanation that you could put an ingredient in a product one day before its expiration date, yet then claim the product has a 2 year stability is pretty much an admission that the expiration dates are relatively meaningless.

  • Anca_Formulator

    Member
    July 17, 2022 at 2:08 pm

    I really appreciate your explanations. So importat to know this stuff. 

  • PhilGeis

    Member
    July 17, 2022 at 11:09 pm

    A critical element of expiration dating is the efficacy of product preservation.

  • Anca_Formulator

    Member
    July 17, 2022 at 11:20 pm

    Thank you @PhilGeis

  • PhilGeis

    Member
    July 18, 2022 at 7:47 pm

    @Anca-Formulator
    What do you think they mean by “expired” in a technocal sense?

  • OldPerry

    Member
    July 18, 2022 at 8:03 pm

    Somewhat related, there was an interesting podcast about food expiration dates. https://overcast.fm/+YsPSDVMLw

    Basically, they say even food expiration dates are not reliable and generally not based on any real scientific standards.

  • Squinny

    Member
    July 19, 2022 at 3:59 am

    Thanks so much for all this very useful information. Really appreciate it.

  • Anca_Formulator

    Member
    July 20, 2022 at 11:56 pm

    @PhilGeis: I’m so glad you asked the question. On the COA, there is a Re-test date. For some reason in my mind I’ve been equating that with ‘expiration’ this whole time, which is not what it actually says!

    But to answer your question, when I think of expiration I usually think of oxidation for oils, and microbial/yeast/mold issues for water-based products. When it comes to emulsifiers and fatty alcohols, I’ve been given them a ‘pass’ for quite some time after their listed shelf-life (different term than re-test), rightly or wrongly. However I have not done any A/B testing b4 and after their supposed shelf life yet, so I can’t support my ‘pass’ with evidence. 

  • Anca_Formulator

    Member
    July 21, 2022 at 12:01 am

    @Perry: Thank you!

  • PhilGeis

    Member
    July 21, 2022 at 4:13 pm

    @Anca_Formulator
    The primary purpose of preservative is to protect the consumer during continued use the the product.  This is reflected in the very flawed concept of period after opening.  That means your preservative must be stable through that period whatever the chemical stability may be.
    “Retest” or recontrol testing (assume for micro) may just be boiler plate - or that they’re no confident in the micro stability of the material

    • anah

      Member
      January 16, 2024 at 2:39 am

      since there’s no way to conduct testing for when it reaches the consumers home, the expiration date/PAO date is only admissible during manufacturing?
      i have skincare products expired 1-2yrs ago and it “looks and smells” the same, what would be the difference in safety if i were to use the expired ones vs if i had opened/used them prior to the expiration date?

  • Anca_Formulator

    Member
    July 21, 2022 at 5:18 pm

    @PhilGeis Thank you for the explanation, I’m still a bit confused though.Sorry for dragging this on. 

    So lets say I want to use a water-soluble extract past the shelf-life the supplier listed in a product and it might be starting to show some microbial contamination, is an effective preservative system for the whole product supposed to take care of that? Isn’t that like fighting with an arm tied behind its back?

    I go to great lengths to sanitize my lab utensils, beakers etc. I also clean bottles received from the supplier with rubbing alcohol (pretty time consuming a pain in the butt really), for fear of not overburdening the preservative. Is that not necessary then? 

    Thank you.

  • PhilGeis

    Member
    July 21, 2022 at 5:24 pm

    I’d not sue a contaminated raw materials.  FDA would consider the product itself adulterated whether it grew bugs or not  and it might even after release.

    Appreciate your professional attention to hygiene and quality - I’d sure keep it up!

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