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PH of product (help)
Hello to all,
i have question regards body lotion. I made one formula that have on end ph of 8.6, i was wondering if you think this is a bit to high? Should i lower with citric acid or keep as it is ?RegardsGreg -
32 Replies
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Yes, that is way too high for a leave-on product. Your pH should be in the 4.5 to 5.5 range. Depending upon your intended use … I’m assuming a moisturizing lotion? … Yes, you can use citric acid or any other AHA’s or combination of AHA’s.
You might also take a look at what ingredient(s) in your formulation drove your pH up so high and see if there are substitutes or lower the amount of those ingredients. -
I have KOH inside, 1st i use koh to get gell from carbomer and when i combine oil and water phase , i add 10% solution to sap stearic acid. So i would say , adding citric acid will work ?
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I do not understand what you mean by “sap stearic acid”?
Apparently you’re making a gel-cream? If that is the case, first make your emulsion (with the Carbomer hydrated in the aqueous phase. As a last step, add just enough KOH to gel the carbomer. Sounds like you are adding way too much KOH. If you’re using Carbomer 940, it will gel at pH 6.0, so just monitor your pH as you’re adding the KOH. -
Sap stearic acid it means, saponification of stearic acid. I use to make gel CARBOPOL ULTREZ 30.
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This is not going to work, ever. When you try to lower the pH the potassium stearate will separate and you will end up with snot. You can’t lower the pH of natural soap, it breaks down.
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This isnt soap, this is body lotion, where you have water, oil phase and gel-carbomer. As nice thickener you saponificate totally stearic acid in emmulsion. I think just ph is a bit high.
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Carbopol Ultrez 30 will gel at pH 4.0. If you’re using Stearic Acid as a thickener, just use a different thickening agent. What emulsifiers are you using?
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Mark, i use cetyl alcohol, Glycerol monostearate and stearic acid
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I’ve always found it easier to use gelling agents other than Carbomer such as Scleortium Gum, Konjac Root Powder, Carageenan since you can eliminate having to neturalize altogether and the flow characteristics are going to be similar to Carbomer. Also, I don’t understand why you are insisting on saponification of the stearic acd. It all depends on what your intended purpose is.
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“i add 10% solution to sap stearic acid”
= soap! What did you think it was? -
I think the issue is the perception that the Stearic Acid must be saponified to function effectively as a thickener which creates an inherent conflict in your formulation. @Rencelj … this is not the case. I would suggest you use a different rheology modifier as mentioned above or you can even add Xanthan Gum if your lotion is not thick enough. Then you can use either Citric Acid or Sodium Lactate as required as pH adjusters. Or, just add more Cetyl Alcohol.
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Ok so looks like i have problem, like belassi said yea will break down when i add citric acid. But i toke mostly formulation from Perry (curse) and (replace some oils with natural) but there it say 5.00 - 5.5 ph and he have water phase and also seperate 5% Thickener Carbomer (2%). So if totally is 100g, than that mean it is 5g of “gel” with 2% carbomer? 4,9g water and 0.1g carbomer ?
can post formulation if need -
Post the formula, please
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Caprylic/ Capric Triglyceride (fractionated coconut oil) 2Persea Gratissima (Avocado) Oil 2Olea Europaea (Olive) Fruit Oil 0,5Cetyl alcohol 1,5Glycerol monostearate 1,5Iso Propyl Myristate 1,5Cera alba (Beeswax) 0,3Stearic acid 0,8
Aqua 81Carbomer 0,1Glycerin 3KOH 1st (i add this to water to react carbomer) 0,08
KOH 2nd (i make 10% solution to sapon. stearic) 0,18Aqua 1,62
I mix oil phase in to water phase and after that i add 10% solution.original formula that i modified it :Diluent Water 82.650Thickener Carbomer (2%) 5.000Humectant Glycerin 3.000Neutralizer Triethanolamine 0.900
Co-emulsifier Cetyl Alcohol 1.000Emulsifier Stearic Acid 0.800Emulsifier Glyceryl Stearate SE 1.500Occlusive Isopropyl Myristate 1.500Occlusive Mineral Oil 3.000 -
belassi talks about natural soap, it mean that KOH+stearic acid gives u natural soap which thickens your body lotion.
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Without delving deep any further I suggest you just increase the stearic acid and eliminate beeswax. Start in increments and I am sure you would end up with a favorable viscosity as well as the pH.
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There are much simpler solutions to thickening his lotion by simply increasing the level of ingredients that are already in the formulation. And, it would simply the formulation. But, to each his own.
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@markbroussard if I use exceed KOH in my lotion(causes high pH), is it true to adding citric acid t? is it good way?
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To be honest, I no longer use Carbomers in formulations because I find them much more difficult to work with than natural gelling agents like Konjac Root Powder or Sclerotium Gum.But, yes, if you overshoot on the addition of KOH to gel your Carbomer, you can use a citric acid solution as a pH adjuster. Or, you can use an alpha hydroxy acid … glycolic for instance. All depends on your formulation.But, it is best technique to add your KOH very slowly while monitoring your solution pH with a pH meter … when you hit the right point, the Carbomer will gel. At that point, stop adding KOH.
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“But, it is best technique to add your KOH very slowly while monitoring
your solution pH with a pH meter … when you hit the right point, the
Carbomer will gel. At that point, stop adding KOH.” thats the best way.
and I have problem with carbomer too, I make hand creams with carbomer 940 and it irritates -
Perhaps it is some other ingredient in your formulation that is causing the irritation. It is not possible to advise you further without knowing your formula.
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Ok, but what if i want to keep stearic acid in lotion ? Someone in past (1year ago) said stearic acid in creams that is not saponified it is useless, any truth in that ? Thats why i am willing to saponif. it. I know i can leave stearic acid and just add cetyl alcohol a bit more or mayby combo with ceteary alcohol will work nice, but want to make “milk lotion” felling. Light and effective.
With formula other things like perservative , fragance , extracts ety are not important, since i am playing with viscosity/ph with base first.Millia, bit more stearic acid (from 0.8 to 2%?) but do i sap. it or leave it un saponificated ? And regards beeswax, any reason to drop it out , or ? Thank you for helpRegardsGreg -
Someone in past (1year ago) said stearic acid in creams that is not saponified it is useless, any truth in that ?
Whoever told you that, was telling you complete nonsense. Stearic acid has been used as a thickener for donkey’s years. It was the reason why “cold” cream was so called, stearic gives a “cold” sensation on the skin.You have around 8.5% of lipids in the formula and only 1.5% emulsifier! This formula is unbalanced and will separate, it’s only the carbomer that is holding it together. Frankly it reminds me of one of my own early hand cream formulae that has the same issue, it is still a popular product but I know very well that without the carbomer it would separate.My advice is:1. Only add exactly the right amount of KOH to neutralise the carbomer. Use the manufacturer’s guidelines.2. The amount of carbomer is too low to achieve a stable emulsion. Increase it to say 0.3% that should work well.3. Remove the beeswax. Increase the stearic acid to thicken. Probably 3% or so will be about the right level but you will need to experiment.4. The avocado oil will remain on the skin so if you get a greasy sensation persisting, remove and replace with an alternative. Actually I suggest replacing it with shea or kpnangan butter which have real benefits for the skin due to the retinol content, and being a solid fat, will thicken.5. Finally, study the HLB emulsification method so you will know how to design emulsions in future.OK? -
If you saponify stearic acid with KOH, you get potassium stearate. This material is available pre-reacted, and there’s a fair bit of information about it on the web. Start here: http://www.hallstar.com/pis.php?product=10277Stearic acid, unsaponified, is a thickener/bodying agent, but not a very good one, although opinions differ. @Belassi is right, though - you will need more of it.In your formula, the potassium stearate is the ONLY emulsifier. This is not a good idea.My suggestion is to use Pemulen TR-1 instead of carbopol. https://www.lubrizol.com/PersonalCare/Products/Pemulen/TDS.htmlYou might also consider using NaOH for neutralizing.
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@belassi what experiment do u perform to test the stability of your cream? do u centrifuge it?
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