On Surfactants and Formulation (face wash, shampoo and shower gels)

So now we know how to combine (and why to combine) the different surfactants… but how to calculate the Active Surfactant Matter we want in our product? (which also mean: how much surfactant we have to add to our product to have the surfactant concentration we want to obtain?).

As I already explained the Surfactant Matter of a liquid surfactant which we buy is not 100%: the surfactant is made of the Surfactant Matter and Water (and probably other ingredients like glycerin, for example); therefore every surfactant we buy has a “Active Surfactant Matter” percentage which is what we have to consider.

As I wrote in the previous posts about formulation of detergents (shampoo, bubble bath, shower gel, face wash), the amount of the TOTAL Active Matter of surfactants has to vary according to the purpose of our detergent.

Generally this is the scheme:
– face wash: <10% 
– detergent for intimate use: <10% 
– shampoo: 10%-15%
– shower gel: 15%-20% 
– bubble bath: 20%-25% (in case you really use it only to make bubbles in the bath tub and you never use it directly on your skin, you could even reach 35%… but I don’t suggest it).

Now let’s learn how to formulate the detergent.

Let’s say we want to make a shower gel, with an Active Matter (once again, the effective concentration of surfactants) around 18%.
We have also already decided which surfactants we want to use:
– Sodium Lauroyl Sarcosinate (Concentration 29%)
– Cocamidopropyl Betaine (Concentration 36%)
– Lauryl Glucoside (Concentration 52%)

There are two different approaches in the formulation to obtain 18% Active Surfactant Matter: 
Approach n.1:
We can choose which share/quota of the total ASM (active surfactant matter) we want to give to each surfactant.
For example this is my choice:
Sodium Lauroyl Sarcosinate 10
Cocamidopropyl Betaine 5
Lauryl Glucoside 3
Total ASM = 18 (as decided)

Now we need to calculate the effective grams of each surfactant that we need to add to our shower gel formula:
We divide the quota of each surfactant by the ASM of the surfactant (in decimals: the ASM of each surfactant is a percentage so if it is 29% we divide per 0.29 OR we divide per 29 and multiply the result for 100… up to you).
Anyway it is easier done than said:
Sodium Lauroyl Sarcosinate (29%) = 10/29*100 = 34,44 (you can add 34.50 gr)
Cocamidopropyl Betaine (36%) = 5/36*100 = 13.88 (you can add 13.50 gr or 14 gr)
Lauryl Glucoside (52%) = 3/52*100 = 5.76 (you can add 5.5 gr)

Approach n.2:
You can also reason the other way around: you try to guess approximately how much grams of surfactants you want to add to the detergent and then calculate the effective total ASM; if the result is not close to 18% total, you change the grams and calculate again until you are satisfied.
For example this is my initial choice:
Sodium Lauroyl Sarcosinate 40 gr
Cocamidopropyl Betaine 15 gr
Lauryl Glucoside 5 gr

Now I calculate the total ASM of the detergent:
Sodium Lauroyl Sarcosinate (29%) = 40*0.29 = 11.6
Cocamidopropyl Betaine (36%) = 15*0.36 = 5.4
Lauryl Glucoside (52%) = 5*0.52 = 2.6
Total ASM = 11.6+5.4+2.6 = 19.6

I can either decide that 19.6 is fine for me or I can decide to lower a little bit the grams or one or all of them and recalculate the Total ASM.
I decide to calculate again changing the value of grams:
SLS (29%) = 35*0.29 = 10.15
Betaine (36%) = 14.5*0.36 = 5.22
Lauryl Glucoside (52%) = 4*0.52 = 2.08
Total ASM = 10.15+5.22+2.08 = 17.45

Now I decide it is fine and I can proceed in the formulation of the Shower Gel! 🙂

Here I post a list of the most common surfactants you can purchase online, with their average Concentration (ASM) and for the most common I will add also few words on how to use them:
(Notice that the value may vary of few points % so the best thing would always be to ask the supplier which is the precise percentage for the exact batch of surfactant you are purchasing: suppliers always have this information, so you are not asking for something impossible; however you can also use these data 😉 ).
IMPORTANT: surfactants may have different commercial names from the substance they are, therefore always check the ingredients list when you purchase 😉

Sodium Lauroyl Sarcosinate – anionic (29%)
One of the most commonly used eco-friendly surfactants. Improves the foam of other surfactants (specially betaines) making it more smooth and soft. It becomes viscous at pH 5, but only if used in high percentage in the detergent (so remember to acidify your detergent with drops of lactic acid or citric acid). It becomes liquid if in contact with oils (perfume oils included) so synthetic thickening agents or xanthan gum have to be used (you have to consider this in the formulation because the xanthan gum goes in the water phase). Not good in shampoos.

SLES – Sodium Laureth Sulfate – anionic (27%)
It becomes very dense once combined with betaine and salt (betaine can be enough). It is very good in shampoos because it has high wetting properties.
It is not eco-friendly.

SLSA – Sodium Lauroyl Sulfoacetate – anionic
It is not aggressive (this term of course is relative) and it is a powder. It is good if used in the making of Bubble Bars (recipe soon ok 😉 ?)

Sodium Lauryl Glutamate – anionic (36%-40%)
Very delicate and used in products for kids. Unfortunately it tends to melt down the viscosity of many other surfactants (therefore formulate accordingly).

Sodium Comopolyglucoside Tartrate/Citrate – anionic (30%)
Delicate and eco-friendly. Used in products for kids and for people who have very sensitive skin. Very low viscosity.

Cocamidopropyl Betaine – amphoteric (30%-38%)
Alone it is not delicate but it makes other surfactants more delicate (specially anionic surfactants) in a ratio of 1:3 or 1:4 with the primary surfactant of the recipe. It is eco-friendly. Combined with SLES it is a viscosity builder.

Disodium Cocoamphodiacetate – amphoteric (36%-40%)
Delicate. It is used in shampoo because it has conditioning properties to the hair (however for thin hair it might be too much). It doesn’t burn the eyes (therefore it would be good in a shampoo for kids or in a face wash). Usually it is used around 5%.

Lauryl Glucoside – non-ionic (50%-53%)
It is a thick, white paste so it needs to be heated a bit to be combined with other surfactants; the good news is that it helps the viscosity of the final product. It is quite delicate and it reduces the harshness of the primary surfactants. Usually added in low percentage.

Decyl Glucoside – non-ionic (63%-63%)
Good foam booster. Unfortunately it tends to liquefy the other surfactants. Usually added in low percentage.

Coco Glucoside & Glyceryl Oleate – non-ionic (50%-55%)
This is a combination of the surfactant Coco Glucoside with Glyceryl Oleate (Glyceryl Oleate is the ester of glycerin and oleic acid. It is produced from oils that contain high concentrations of oleic acid, such as olive oil, peanut oil, teaseed oil or pecan oil. Source Here), which limits already the harshness of the first. It is added in low percentages (3%-4%)

Lauryl Glucoside and Cocamidopropyl Betaine (43%)
This is made of already two combined surfactants

Coco Betaine (29%-33%)

Coco Glucoside (51%-53%)

Disodium Laureth Sulfoccinate – anionic (35%)

Hope this was clear enough 🙂
Next time I will show a full recipe of a detergent (I still have to choose between a shampoo and a face wash but anyway sooner or later I will post both).

If you want more posts about how to formulate Shampoos check HERE

Let me know if you have any questions 😉

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

38 thoughts on “On Surfactants and Formulation (face wash, shampoo and shower gels)

  1. Robert says:

    Hey, great! Maybe sometime I’ll write about all the decisions & compromises that went into my formul’n of the stuff I linked to here. Susan Barclay-Swift is the only other writer I know of online for DIY of such mixtures.

    I would take issue, though, with your use of the catch-all term “detergent”, because although it fits the other products you categorize, it’s a little off base for bath foams, because when used in bath water they’re too dilute to be effective cleaners for skin. However, I have no short alternate term that encompasses skin & hair detergents along with bubble bath.

    I also take issue with people who distinguish soaps from detergents in these contexts–because if you’re using soap to clean, it is a detergent–as well as with scientists who use “detergent” as a synonym for “surfactant”, even when the material isn’t intended for cleaning. And there are detergents that aren’t surfactant-based. It’s a functional category, not a chemical one.

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    • It's all in my hands says:

      Thank you for your comment!

      Indeed I wasn’t sure about using the word “detergent” but I am not English mother tongue and I couldn’t find a better word to refer to what I am talking here 😀 Suggestions? 😀

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      • Robert says:

        Since the only other major toiletries product I can think of that uses similar surfactant compositions to the detergents are bath foams, you could say “detergents and foamers”. To be a little more specific you could write “water-based detergents and foamers” if you wanted to leave out oil-based products and adsorbents such as dry shampoos. But the description starts to get unwieldy, so if you just write “detergent” or “cleaner” or “cleanser”, you cover most of the ground in few words.

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  2. Angel says:

    Hi, please i need some help.. im trying to make a sulfate free shampoo by using sodium lauroyl sarcosinate in replacement of the sodium lauryl ether sulfate but i cant get the product to thicken at all.. i thought that lauroyl glucoside would of thicken the product but it didnt.. Can you guys guide me with which chemical is needed to thicken sodium lauryl sarcosinate..

    Here is the list of ingredients im using:
    Sodium Lauroyl Sarcosinate
    Lauroyl Glucoside
    Glycerin
    EDTA
    Citric Acid
    Desmineralized water

    Thanks

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    • It's all in my hands says:

      Hello there! 🙂

      Eh… Lauroyl Glucoside HELPS to thicken but it won’t thicken your Sarcosinate… cause THAT is the problem.
      You see, Sarcosinate thickens only at pH 5 and I think it works quite well combined with Cocamidopropyl Betaine; the Lauroyl Glucoside is fine but shouldn’t be used at high percentages so it won’t make the trick.
      Anyway, as I said, Sarcosinate thickens at pH 5 sharp… but the problem is that it doesn’t “bear” any kind of oil (if you add even just few drops of fragrance oil – the shampoo is liquid again!! 😀 ).
      If you wanted to make it thick I would suggest you use a gelling agent of the water phase (xanthan gum, for example… or maybe Sclerotium Gum! I think it might work great!).
      However, just my suggestion, I wouldn’t make a shampoo based on Sarcosinato simply because it has an awful wetting ability (all the opposite of SLES)… but that’s cause I have long thin hair 😀 so if you have short hair it might just work great for you! 😉

      Hope it was of some help 😀
      Have a great day!
      🙂
      – C

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      • Robert says:

        It’s true that sodium lauroyl sarcosinate doesn’t have great wetting power and doesn’t “bear oil” in concentrated solution, but it has a virtue as shampoo in that it works very differently with oil once diluted: its lather stays thick and on your head as it picks up scalp oil, rather than breaking and running off as most do. Pretty expensive stuff, last I checked, as surfactants go, but usually even expensive surfactants don’t turn out to be the major cost in products like this.

        As to thickening, other than the pH adjustment suggested above, the trouble with sodium lauroyl sarcosinate is that it doesn’t want to jell, but simply to precipitate out, so you can’t just add a sodium salt to get the common-ion effect for viscosity. So I’d go with a gum, a polymer carbohydrate, a carbomer, or something, if the formulator doesn’t want to switch surfactants.

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  3. Angel says:

    Hey thanks for the quick response!
    After some various tests we have noticed that the reaction of Cocamidopropyl betaine with sarcosinate and lauroyl glucoside seems to thicken the formulation to certain extend..
    Also Adding Cocamide(DEA) to the formula seems to thicken it as well… on the other hand adjusting the pH sounds like a great idea! I havent tested it yet.. my only concern is that the pH is going to be too acidic.. the shampoo is going to be aimed as dog shampoo.. so a neutral PH would of been ideal for their skin.. We are trying to develop a sulfate free shampoo thats delicate and not harsh to their skin.. for that reason we chose sarcosinate and lauroyl glucoside as main ingredients in the formulation..
    Its true basing the formulation with only sarcosinate might be an expensive way to do it..Can you guys suggest which other surfactant can i use in conjuction with sarcosinate and lauroyl glucoside to reduce costs??

    Thanks

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    • It's all in my hands says:

      hmmmm I am not sure actually of which other surfactants might be cheaper, to me, in fact, they all cost very similar – except for the very cheap SLES which you don’t want to use – the others have similar costs where I buy. 🙂
      However… about the pH being too acid for dogs… I don’t know cause I am not an expert about dogs but pH 5 doesn’t sound very harsh to me and, also, consider that you have to rinse it off completely (therefore there is water bringing the pH back to neutral), so I am not sure but I wouldn’t worry too much about that! 🙂
      IF the pH adjustment works, I would just go with it! 🙂

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    • Robert says:

      Usually cocamide DEA (or any alkanolamide) is going to bring in some alkali, so I wouldn’t be concerned with its lowering pH (may raise it, though). However, the ethanolamides tend to sting eyes, which you wouldn’t want in dog shampoo. By my direct observ’n, lauric DEA stings eyes worse than soap; coconut diethanolamide less so, but still considerably.

      Many pro dog washers use human baby shampoo on dogs. The ingredients of those are also slightly expensive, though maybe less so than sarcosinate. Typically no-eye-sting shampoos have been heavy on highly ethoxylated derivatives of glycosidic and/or of monoglyceride surfactants, and have been buffered to neutral pH with citrate, borate, or phosphate buffer, and don’t concern themselves too much with viscosity. In fact, you probably would want a less viscous liquid for washing dogs, because you want to pour on a lot of it and spread it quickly on wet, squirmy bow-wow. An adult human user may want to put a little viscous liquid on wet hands and pre-lather it before putting it on the head, but a dog washer is going to be holding the wet dog in one hand and pouring shampoo on it with the other.

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  4. Debbie Blyth says:

    I have read the articles and used Approach #1 in the above article to figure out how many grams of each of the surfactants I could add to my bubble bath. I used your 25 ASM as the goal. I assigned values to the 3 surfactants and ended up with 37gm; 21 gm and 12.7 gram. What do I do with those numbers of grams? I would like to experiment but I dont want to waste ingredients. Do I make a surfactant that is topped up to a 100 ml surfactant AND THEN use the BLEND as the surfactant in my bubble bath? For instance, a recipe asking for 50% surfactant of my choice-Would I use my BLEND at 50%?

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    • It's all in my hands says:

      Hello Debbie.
      It would be correct but there would be two problems:
      If you do like that, you would end up with a mix that you could never change.
      Secondly, surfactants are preserved so it sounds like it would be fine but it is not: the different pH and the different composition (plus the probably different preservatives used) dont make for a stable mixture to be kept in the shelf just like that. You would have to add some kind of preservative and then, once you make your final bubble bath, you would have to add preservative there as well. Doesn’t sound like a very good option.

      So, do like this: formulate your bubble bath and make just one batch of it.
      Now you know the amount of grams of each surfactant that you need to use in order to make your bubble bath…
      Just remember: you have to reach 100 grams total 🙂
      So you can add a gelling agent, if you want a very thick bubble bath, you will have to add water (but you calculate its amount in the very end), and then you can add other things as well… 1% oil? (but remember your bubble bath will make less bubbles 😉 ), 0.25% caffeine? (for a good wakeup 😀 )… just anything you want.
      Don’t forget you have to add the preservative as well.
      Then a good smell 🙂

      I made many detergents (mostly shampoos, but the procedure is the same) so you can find a recipe on my blog just as example and then you can make your own 😉

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      • Debbie says:

        thanks, for the reply. It was a big help. I appreciate your site and I will enjoy following it as well.

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    • Robert says:

      I took some shortcuts in formulating my bubble bath because I wasn’t originally intending to make a commercial product, plus I got a little lucky. To figure out the proportions of 3 surfactants (sometimes I used 4), the way I experimented was by starting with free sample solutions of the surfactants (which manufacturers were more eager to supply in those days), and pipetting each separately into bath water, recording the amounts. So in the experiments, the ingredients wound up mixing only in the bath. Then I splashed & saw the foam’s characteristics. A few rounds of that, and I’d figured a range of proportions and overall quantity of active matter. I actually shipped the components separately to the family I made it for, and had the children mix it in the bath, which they loved doing. (When it comes to solutions for blowing discrete soap bubbles, it turns out the surfactants & other ingredients benefit from time sitting mixed together in concentrated solution, but when it comes to foam-making solutions, not so much.)

      When it came to making it as a product that could be sold, my task was simplified by the fact I wanted an unfragranced & uncolored product. I got lucky in that the surfactant solutions all had the same preservative, and in the same concentration; but that’s not a great streak of luck, because that’s not an uncommon circumstance. I decided to add no water, which meant the mixture would have the same concentration of preservative each surfactant started with. It meant the total active matter would be in the range of 30-40%, which is certainly no problem with bubble baths. (I’ve read that Badedas, which was to be used either in bath water or on a wet cloth, was at one time around 60% TAM.) I wasn’t aiming at a precise concentration of total surfactant actives, but only the proportion; TAM calculated out nominally to 36.7%. I also got lucky in that the solutions mixed well without dilution, as long as they were mixed in the right order; gelation was a problem if a certain couple ingredients were mixed first. Also, the betaine surfactant included was a good pH buffer, and although different samples of it came in at different pH, they were all in an acceptable range. Eventually the mixture did become nonuniform, but that was after many years, due to the slow breakdown of the sulfosuccinate surfactants included, and my inability to sell much of the stuff!

      If you’ve already determined that your surfactants foam together the way you want in a certain proportion, then your approach of making a blend & using it in different mixtures is OK if all you want to vary are minor ingredients. It’s still possible that one fragrance oil (or mixture thereof) will affect the foam or viscosity more than others, especially if you need to add more of one than another in different versions of your product.

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      • It's all in my hands says:

        Thank you Robert.
        I never liked foam in the bath, so I never thought of taking advantage of the fact that, if not mixed together, surfactants are “stronger”. I always saw it the opposite way: to make a milder detergent, i mix certain surfactants that, if taken alone, would be more harsh!
        So thank you!! 🙂

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      • Robert says:

        I wasn’t trying to take advantage of any increased harshness or “strength”, far from it! What I meant was that if you’re making a solution for blowing discrete bubbles, it helps to let the mixture age for a while. This is well known to makers of bubble blowing solutions. At one time I scoffed at that notion; I figured, these are all small molecules, they should equilibrate quickly, unlike large molecules like proteins, with no big free energy barrier to their flipping around at an interface. But while that may be true on the level of individual molecules, apparently when it comes to a mass of even small surface-active molecules, statistically it takes them a while to settle into a structure in solution — like at least overnight, maybe days.

        But that doesn’t seem to be the case for foaming solutions such as those of bubble bath, maybe because they’re used at high dilution or maybe because it’s different when you’re not trying to blow large bubbles. So you can dilute the ingredients separately in the bath water (or test cylinder), stir the water to mix it, and it acts the same as if the foaming ingredients had been pre-mixed. At least I haven’t been able to tell a difference. It speeds up testing a lot when you can do this.

        And I did test a lot. My aim was to make a foaming composition that could be tolerated at relatively high concentration for long periods by a friend’s daughter without causing the urogenital irritation she’d experienced when taking bubble baths with her younger brother & sister, or when playing with shaving cream in the bathtub. I took a guess that sulfosuccinate-betaine mixtures would be at least as mild as a linear combination of their properties separately, and I hoped they would be even milder, as had been shown with ether sulfate-alkamidopropyl betaine mixtures. The sulfosuccinates would be the primary foamers, the alkamidopropyl betaines secondary foamers and also foam stabilizers. At first I tried lauryl sulfosuccinate & lauramidopropyl betaine, and found that if the sulfosuccinate predominated, the resulting foam was very dense, which would be good for children who liked shaving cream (Don’t they all?), but not so voluminous to begin with & not very stable, which was a disadvantage because these kids stayed in the tub sometimes for literally hours at a time. So I tried adding variable amounts of laureth-3 sulfate, and found definite tradeoffs between density and volume + persistence of the foam. I found a proportion they liked and which the one with the sensitive crotch tolerated no matter how much or long she sat in the bath.

        But once friends encouraged me to try to do more with this, I found sensitive-crotch test subjects for whom it made a difference whether ether sulfate or ether sulfosuccinate was used, and I settled on a mixture whose anionic surfactants were all sulfosuccinates. I found other anionics could be used instead along with the lauryl sulfosuccinate, but it seemed using the ether sulfosuccinate would be my best bet in terms of mildness. I also played around with the alkamidopropyl betaine, and found that a ratio of 3:2 or 2:1 lauric to palmitic amidopropyl betaine made it more skin-softening and produced a more cottony foam while sacrificing very little in foam volume and nothing in foam persistence. However, palmitamidopropyl betaine was too hard to obtain in an affordable small production quantity. Other alkamidopropyl or alkyl betaines gave inferior foam in these mixtures.

        To get a US patent (which has expired), I came up with an objective test of the density of the foam in a cylinder shake test, which was to weigh a fixed volume of the foam. However, it took an assistant at a lab I engaged for the purpose to come up with a practical way to pack foam into a vial: drill 5 small holes in the bottom to prevent an air pocket.

        So I encourage people trying to formulate such products to play around like this with surfactant solutions using graduated pipets and a bathtub, sink, or clear plastic cylinder to see how the foam acts. If you have friends with young children, they’ll tell you how it behaves when they splash & play with it, get it in their eyes, etc. I believe some of the newer formulas (such as using sucrose esters & various synthetic glycolipids) surpass mine in terms of mildness for a given foam height or persistence when allowed to settle, but I doubt they beat it yet for density or resistance to breakage when being played with, for the same degree of mildness.

        Some people are now moving away from ethoxylated surfactants because of contamination with 1,4-dioxane, which is a probable weak carcinogen. I still believe in using ethoxylates, whose dioxane content can be considerably reduced, but mostly because even if all ethoxylated surfactants were taken out of toiletries and hand dish detergents, they’re practically indispensable for now in formulating low suds laundry detergents, which are all the more needed with HE washing machines, and there are many uses for polyethylene glycol, which even shows promise in, of all things, cancer prevention! I’m afraid taking ethoxylates out of baby shampoo, etc. to reduce dioxane exposure would be something like a smoker who stops barbecuing to reduce exposure to smoke.

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  5. Debbie says:

    To It’s all in my hands: I have another questions concerning the formulation of my bubble bath. I am trying to duplicate a bubble bath that I already use. Water is the first ingredient on their label. When I calculated the grams of each surfactant using the ASM calculations above based on use of the same surfactants that they have listed on the label, I am finding my surfactants are taking up to 78% ( with the larger at about of the surfactants calculated at about 45 grams) and obviously I can’t proportion water a higher gram than that. QUESTION: How are they able to make water the largest ingredient by weight? I wondered if it because they recognize that the liquid surfactants are mostly comprised of water or is there another explanation I haven’t considered? Thanks

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  6. Gugu says:

    To It’s all in my hands: I am a mother who is interested in making an organic hair shampoo for my daughter, however I have little information on organic ingredients. On the list of surfactants above, is there an organic surfactant?

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    • It's all in my hands says:

      Hello Gugu. There are many so called “organic surfactants” and if you check some online resellers of cosmetic ingredients they should give you all the data. However: if your daughter has long hair it can get tricky: the surfactants with the best wetting ability are not “organic”. On the other hand, it is true that nowadays you can even purchase shampoos with good ingredients at a low cost.
      I wouldn’t worry too much about “organic” surfactants in a shampoo, I would worry more in finding a delicate shampoo (with “as good as possible” ingredients). This is just my idea but if you think about it: a shampoo touches our skin for a very short amount of time, the worst thing it can do is to irritate and dry the scalp. I have posted a recipe of a No SLES shampoo (SLES is a great surfactant for a shampoo, however it can irritate in the long run) that should have good ingredients (actually I have no idea if a surfactant can be “organic” but those in this recipe are at least “eco-friendly”).

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    • Robert says:

      The only system I know of for classifying products as “organic” apply to foodstuffs according to rules regarding how they’re grown. Surfactants of the kind you want may be available from fats or oils that would be considered organically farmed, or not. However, is that actually your concern in making your daughter’s shampoo, or are you meaning “organic” in some other way?

      Liked by 1 person

  7. Eman says:

    Hello ..im trying to make free sls shower soap with olive oil &koh..but the problem is that the foam is not enough .can i add any surfactant like coco amid propyl betain &lauramid ? To increase the foam
    Please reply ..
    Thank you

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    • It's all in my hands says:

      Hi Eman.
      You want to mix a liquid soap with a detergent. Not a very good idea.
      Why don’t you make directly a detergent without sls? Most detergents don’t contain sls anyway, but at least the pH would be better than the one of liquid soap!

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      • Robert says:

        A mixture of potassium olivate (the liquid soap solution Eman is contemplating) with other surfactants may not be the BEST idea, but it’s not necessarily a bad one. Various mixtures of soaps with other detergent surfactants have been commercially or at least technically successful. In particular, soap + cocamidopropyl betaine, and soap + lauric diethanolamide, both suggested by Eman, have been done, although the soap wasn’t pure olive oil soap in the examples I know.

        Olive oil soap is known to be a rather low foamer, and is usually chosen for mildness. (Also for label or ad appeal, being expensive.) Cocamidopropyl betaine will almost certainly boost its foam, promote rinsing, and possibly even enhance mildness. Lauramide DEA (lauric diethanolamide) will boost foam & viscosity of the solution, and requires only small amounts, but may increase eye sting & waterlogging of skin. Lauramide DEA’s been out of favor for some years due to a cancer scare resulting from a routine test in rodents, but I believe that result to have been a fluke and not to reflect any actual danger. Either of those ingredients mix well with soap solutions and may be preserved by the same preservative as soap solution; one’s choice of preservatives active at the pH of a soap solution are limited, but once you’re satisfied with whatever you were going to preserve the soap with, the other surfactants won’t present any additional problem. Both of those surfactants are also stable at the pH of soap solutions.

        One possible problem, though, is that if there’s a significant amount of free dimethylaminopropylamine in the cocamidopropyl betaine solution, it will stink when mixed with soap. You might be able to reduce the odor to an acceptable level by mixing in an open container until enough of the amine evaporates, or by overcoming it with perfume. You cannot deal with it by neutralizing it with acid, because of the soap in the mixture.

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    • Robert says:

      To the extent superfatting works, that would be predicted, because usually liquid soap makers strive for a clear solution, which they can’t get with superfatting. But I think the “aggressiveness” of a soap formula would be influenced more by its fatty chain profile than by superfatting. Just a hunch based on things I’ve read & remember vaguely, rather than much experience. If my hunch is correct, all the superfatting you could manage with, say, coconut soap would not make it as mild as olive soap.

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    • It's all in my hands says:

      You can mix soap and surfactants BUT I don’t really think it is done like that: if you add SLSA at trace it means you are adding it when the soaping process has just started and it doesn’t sound right to me.
      For what I know syndets are done differently.
      But why do you want to add SLSA to your cold process soap? What do you want to obtain?

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  8. Zwe Zarni Win says:

    Hi Mr!
    I’d like to request you to answer me about the ASM value of Sodium Lauryl Sulfate.
    Thank you

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    • It's all in my hands says:

      I am not a Mr. Anyway you can find this data on the MSDS of the ingredient that you purchase. It should be around 30% more or less, but do check on the MSDS because these values vary depending on where you purchase from!

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    • Robert says:

      Usually SLS solutions are sold at a nominal 30% actives (w/v) in water, the specs saying something like “at least 28.5%”. However, it can also be obtained in alcohol-water solutions at 60% or 70%; those don’t get promoted much for use in toiletries, but they’re out there. And it can also be gotten as a powder or noodles which might be 88%-97% surfactant, the remainder consisting almost entirely of sodium sulfate. Don’t waste your money buying electrophoresis grade!

      Liked by 1 person

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