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

  1. Thanks for the information. Please what can we combine with coco glucoside? I mean eco friendly surfactants. Or can you help me with any 3 eco friendly surfactants that can be used together.


      1. I used castile soap, sodium lauryl ether sulphate and cocamidopropyl betaine with Sodium coccyx isethionate and coco glucose and it foams but not quite enough. Am I missing something? Does water need to be added. You really know your stuff can you give me the perfect percentage for the above ingredients to make the best foaming body wash?
        Thank you for your time.


      2. Hi,
        I don’t like using castile soap with surfactants.
        I believe SLES and CAPB already create a lot of foam, but there are better foam enhancers surfactants out there that need to be added just at 2-3% to increase the bubbles and make them stay.
        Try adding Sodium Methyl Acyl Taurate.

        Ps. What do you mean by asking “does water need to be added?”
        Indeed it does, you need to understand the basics of formulation and do the calculations to know how much water to add.


  2. I want to make a face wash that has been discontinued for a long time. I have been trying to figure out the percentages. Any help or articles would be great. I have very sensitive skin and this made my face the happiest! Ingredients are: water, sodium Lauren sulfate, sodium chloride, cocamidopropyl betaine, polysorbate 20, glycerin, coconut oil, tea tree oil, dmdm hydantoin


    1. I used to do this as a job. Of course, without having tried this face wash I cannot really help with suggestions on the percentages.
      Anyway coconut oil, tea tree oil are probably very low (I’d say lower than 1% together)


  3. I want to make a face wash that has been discontinued for a long time. I have been trying to figure out the percentages. Any help or articles would be great. I have very sensitive skin and this made my face the happiest! Ingredients are: water, sodium laureth sulfate, sodium chloride, cocamidopropyl betaine, polysorbate 20, glycerin, coconut oil, tea tree oil, dmdm hydantoin


  4. HI I’m trying to make a shampoo ‘as natural’ as possible. I’ve used Sodium Cocoyl Glutamate 8%, Decyl glucoside 7% and Lamesoft 5% with 4% oils. It’s not very foamy and it does not last. Is it possible to make a good cleansing, foaming shampoo with this combination. The shampoo is for really dry hair so didn’t want to remove the oils completely. Thanks


    1. For dry hair I would use maximum 1% oil. Dry hair tend to be dry on the length and oily near the scalp so you want to be able to wash the scalp properly without drying it. So add hydrating compounds instead (like glycerine, for example).
      Adding oils will just make the hair dirty, the shampoo not foamy and the scalp oily.


  5. Hi,
    Thanks for your articles. They are very helpful. Can you tell me if polysorbate 20 and disodium lauroamphodiacetate are both usually diluted when purchased? I can’t see the % active surfactant matter on the container or on the website I purchased them from. Also, I read here and on another website that face washes normally have less than 10% of active surfactant in their formulas. Yet, when I look at a number of free face wash formulations online, they seem to contain quite a bit higher % of surfactants. Just wondering why that would be?


    1. Yes if they are liquid they are diluted.
      Having less than 10% of active matter is very different from having less than 10% of surfactants (exactly because of the dilution).
      Also, please notice 10% is a guideline, not something that is strictly followed. I have even made face washes with 15% active matter 🙂


  6. Hi,
    When you look at a pre made cosmetic formula and they list a % required for a surfactant in the formula and they don’t explicitly state the ASM for that version of the ingredient they used, are we to assume the % required that is listed in the formula is for if the surfactant was at ASM 100% and not diluted OR are we to assume the % listed as required for the formula is based on the typical average ASM concentration for that surfactant?? I tried to word my question as clearly as I could😊. Hopefully it makes sense. Thank you.


    1. Usually they include a specific brand for the surfactant (and so the formula is meant for that kind of surf which has a specific ASM%) or they are written for general surf (for example CAPB is usually 30-35%)
      It isn’t that common to use 100% ASM surfs in a formula (though not impossible) but you will be able to see when it is the case by checking the procedure of the formula.


  7. Hi, I find your blog extremely helpful and super clear, so THANK YOU so much for it!.
    I have a question regarding something you wrote above: why would sodium lauroyl sarcosinate not be so good in shampoos?
    Thank you


    1. Well thank you for your kind words.
      SLSarcosinate is not very good on hair as it doesn’t have the same wetting abilities of SLES for example. Is is ok if hairs are short, but with long hair it doesn’t give a satisfactory sensation in my opinion. They feel like they get tangled a lot, even if you add some conditioning agent.
      That’s it 🙂


      1. I don’t think sodium lauroyl sarcosinate is BAD per se, but:
        1. It’s expensive!
        2. It’s not so efficient as the primary surfactant in a shampoo, for reasons like our host stated.
        Sodium lauroyl sarcosinate, when wet, doesn’t FEEL LIKE it’s penetrating thru the hair. It doesn’t have much of a soapy-slippery feel to the lather. Whether it’s ACTUALLY weak at wetting I’m not sure, but it’s hard to tell, so you may wind up using an excess of it, especially with a thick head of even somewhat oily hair. I used a solution of it alone once to wash my hair, and it came out squeaky clean while giving the impression I’d used too much because I couldn’t feel it working. It was like I’d laundered my head in low suds detergent!

        For those who like fluffy lather, sodium lauroyl sarcosinate is far from spectacular, although FUNCTIONALLY that’s neither here nor there. Still, it doesn’t get much use in shampoos, although it may be used in a lot of mild skin cleaning products as one of the surfactants in a mixture. It seems to work better in applications where it’ll be used at high dilution, such as toothpaste.

        Liked by 1 person

  8. Hi! Thanks for sharing all of this information!!
    I have been learning and searching about all the ingredients, and I saw that Cocamidopropyl Betaine is sometimes allergenic to some people and the SCS is also irritating to some who have sensitive skin.. (The SLSa is not available in my country to buy).
    So, it is so bad idea to use only SCI, coco glucoside as surfactants? Because I know that is necessary to mix two or more different surfactants as SCI and SCS/SLSA.. Or it is worst to use only SCI or to use both with this risk?
    Any indications of posts/eBooks would be nice!
    Thanks in advance!!


      1. Thank you for the reply!
        Do you have some information about the maximum irritative potential of SCS? If I dont use SLSa, will be 40% SCI and 20% SCS but I dont know if 20% is irritative..


      2. It doesn’t work in these kind of percentages:
        1) because a lot depends on the blend you create which can make things worse or better
        2) because people have different scalps so what might irritate a sensitive scalp might not irritate a normal one.
        3) what active matter % are you talking about exactly?


      1. solid shampoo bar..
        I have been trying some formulas..
        Also 49% SCI and 25% SCS (ASM around 65) (if CB is not irritative depending on the quantity, I could try 4% – ASM also around 66).. There is something to be concerned with?


      2. Solid bars aren’t the easiest to formulate and they do tend to be quite aggressive simply because the ASM is so high (so if massaged directly on the head they can be absolutely much more irritative than a normal shampoo). If you are concerned with irritation, I wouldn’t formulate a shampoo bar.
        Anyway I am all for “trying” and “experimenting” so you could try making one and simply seeing if it is ok for you.
        CAPB can irritate, but so can SCI and SCS.


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