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Are these preservatives and pH 10 enough for this shampoo?
This is my shampoo formula
Active ingredient
SLS 3.5%
SLE2S 4%
CAPB 1.5%
Cationic guar 0.2%
Amodimethicone micro emulsion 1%
EDTA 0.2%
Nacl 1%
CMI MI 2.8ppm
Formaline 0.02%
Citric acid 0.01%
I want to make a version of this shampoo at final pH 10 strongly buffered.
Package is 500ml flip-top bottle.
Is this preservative system and pH 10 enough for preservation?
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12 Replies
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I doubt you’ll have a micro problem but why buffered pH 10? Drop the CMIT - it’s not stable at pH 10 - EDTA/Formaldehyde/alkaline pH are uniquely effective and you’re not going to find too many bugs happy with the pH.
BUT buffered at pH 10 - risks substantial hair damage.
https://onlinelibrary.wiley.com/doi/abs/10.1111/ics.13029
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Thanks.
I was using these preservatives at my other product at pH 6.
I thought adding them to this high pH shampoo will do a quick kill of existing bugs that are introduced during production and before the preservatives loss there effectiveness. what do you think about this idea?
Also formaline is 0.02%. will be effective alone without CMI MI at that small amount?
For high pH shampoo, it would be in contact with hair for ~1 minute and then rinsed with water which has pH ~7. So in that 1 minute, would it matter if it is pH 4, 6 or 10?
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0.02% formalin - 74 ppm formaldehyde at high pH and EDTA -this is prob good enough.
Objective if preservation is to protect consumers - CMIT will be long gone. If buggy ingredients get some good stuff.
I’d not be confident that rinsing will prevent damage.
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I don’t have full access to the document. Was it about high pH leave on product or rinse off product like shampoo?
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This one doesn’t how if high pH is bad for hair or how much bad it is.
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I agree with @PhilGeis Also, high pH will impair coacervate deposition which is favored by lower pH. To prevent contamination of the product, I’d rely more on the preservative system rather than a high pH.
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I have made this shampoo and all of our employees have tested it as shampoo and face wash.
As shampoo they liked the conditioning effect the most. Only one women said foam is a bit less which is obviously from low surfactants. No other complains.
As a phase wash aso only one of 10 people which has very high acne complained about it irritating her phase. Others saw no difference with low pH phase wash.
As guar and amodimethicone are still cationic at pH 10 and hair is more negativity charged at pH 10, why deposition of these cationic ingredients decrease instead of increase?
Chatgpt also says deposition would be higher at pH 10 compared to pH 6 hahah. but i know i shouldn’t believe chatgpt.
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I’d be very cautios about consumer testing with small groups (although I understand that it’s sometimes not possible to do it otherwise). Compare the results of your tests always against published data.
About the pH, there are 2 things to consider: 1) keep in mind that the coacervate is initially dispersed in excess anionic surfactant in your shampoo; at high pH the surface of hair would be too anionic, which make the first interaction not favourable for deposition. 2) the coacervate itself is less soluble at low pH which makes it deposit easier.
There are now tons of studies on the benefits of low pH on hair, and specially of organic acids so I’d advise you to check on those.
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@Abdullah I correct myself on the topic of low pH shampoos. I rechecked the information and the effect of pH on hair is real (this is a nice read: “Effect of equilibrium pH on the structure and properties of
bleach-damaged human hair fibers”), but even though there are many products claiming low pH, there are no studies that I could find where actual products were tested (the study I mentioned used water solutions of different pH). Before considering any effect on the pH, we have to consider first the high viscosity of shampoos for instance and their little contact time with hair. Not saying it’s not possible, but I haven’t found any solid study where this is shown.
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You can’t evaluate product sush shampoo with one ,two or even three washes only .I guess for more washes all we complain about it .
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This reply was modified 14 hours, 27 minutes ago by Fekher.
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This reply was modified 14 hours, 27 minutes ago by
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