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Sodium benzoate and SLS in toothpaste
Since cocamidopropyl betaine is known to counteract the “harshness” of SLS, I was thinking of using the following in a toothpaste.
I would want to use the same combination whether making a calcium carbonate or silica-based toothpaste…
0.5% SLS
0.5% cocamidopropyl betaine
0.3% sodium benzoate
I this a good idea, or a horrible idea?
I await response(s) with baited breath ????.
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10 Replies
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CB is gentle but not for eczema, I love castille soap for toothpaste. I’m not sure if it works in anything other than homemade toothpaste but its super gentle.
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CAPB is one of the mildest avaliable surfactants. It can produce some skin issues to people with specific skin allergy to the ingredient, which is rare. To be safe, always formulate it along an anionic surfactant (wich will hinder both polar heads by forming a mixed micellar system) and at a low pH (which will neutralize amidoamines and other basic impurities, which can be present in traces). Also, regarding the safety of soaps, better take a look at the available evidence like this CIR review: cir-reports.cir-safety.org/view-attachment/?id=3a3ac6dd-8c74-ec11-8943-0022482f06a6. Our own experience is considered as anecdotal evidence, which is the lowest level of evidence possible. We always need to search for systematic reviews on the topic (like this one from CIR or the Opinions from the SCCs of the EU).
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I find the amount you need to use depends very much on the taste of the finished product and also how much it foams and adjust the amount accordingly.
If, you are using essential oils to flavour, you may require more SLS/CAPB - the oils seem to knock the foaming back a bit, you may find you are using too much if you use a commercial flavour.
Also, if you are going for fruity flavours (or non-mint flavours) you may find the flavours of the SLS/CAPB come through a bit more and you may need to adjust.
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@PhilGeis Just wonder what your opinion is on this new boosted Na benzoate that “works” at pH as high as 8.5. This new preservative has Na benzoate, EDTA and polyamine. I don’t see how this mix can do the magic, but maybe it’s just my brain limitations…or maybe it’s one of the many fairy tales from suppliers.
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I’m not the sharpest knife in the drawer….but there is a brand that rhymes with GeoTard, that says their organic acid based preservative will work at something like 8 or 8.5. 😅 Hey, if your gonna pull BS…might as well go big!
It appears as all my books….are out of date. My how chemistry has changed since I slept! 😉
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SLS and prob some other surfactants change the apparent pKa of Benzoic acid enough to preserve efficacy approaching 8. Used this in P&G shampoos.
Maybe these guys have found the same effect with polyamine. Wonder that it’s enough to function that well in finished product (even even at the recommended the 2-3% level).
https://www.sciencedirect.com/science/article/abs/pii/0001868689800028
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They are using those fun words “Broad Spectrum” we all love so much. Correct me if I am wrong Dr Geis… aren’t the benzoates/benzoic weak on Gram -, even under ideal conditions?
Albeit they are focusing our attention that their product is used by ‘WalMart’, so I guess that is a pretty high standard to be held…. 😉 (Isn’t that the same bar that P&G and L’Oréal use?)
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Yes - Gram neg’s (esp.pseudomonads) can “eat” benzoate.
Walmart - yup. Walmart’s contract packer’s formula.
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Thank you @PhilGeis and @graillotion for your comments!
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I asked ’em for data - let’s see what they say.
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