How to formulate a detergent – THEORY pt.2

LAB NOTES & SAFETY NOTICE
These are personal experiments for educational use only— not instructions and not for commercial or consumer use. By proceeding, you assume all risks related to safety, testing, and regulatory compliance.
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How to formulate a detergent

My Lab Notes: Surfactant Assembly & Phase Logic

Hello Hello! 😀

I’ve been recording my experiments with detergents, and I’ve realized it’s about so much more than just getting the skin clean. It’s about managing the “Micellar structure” so the product feels professional.

1. My “Trio-Strategy” for Softness

I’ve documented that a single-surfactant system is usually too harsh for my skin. I’ve started using a three-part team:

  • Primary: My “cleaning engine” (like SLES).

  • Secondary: A “buffer” like Cocamidopropyl Betaine to reduce irritation.

  • Aesthetics: A tiny bit of Glyceryl Oleate to make the lather feel like luxury.

2. My Thickening Observations

I’ve noticed that people associate thickness with quality, so I’ve been testing three reliable ways to build “body”:

  • The Salt-Curve: I’ve recorded that SLES becomes extremely dense when I add electrolytes (salt) because it forces the micelles to pack tighter.

  • The pH Trigger: In my experiments with Sarcosinate, the texture changes completely at pH 5.0. It goes from thin to thick almost instantly!

  • Polymeric Support: If the surfactants are being stubborn, I use Xanthan Gum (<1%) in Phase A to get the flow I want.

3. My Assembly Protocol (Avoiding the “Crash”)

I have to be very careful with the order of addition to avoid “crashing” the formula or making it cloudy.

  • Phase A (The Aqueous Foundation): I hydrate my gums and glycerin here.

  • Phase B (The Concentrate): This is where my main surfactants go. Sips water. I’ve learned to mix these very slowly with a spatula—no immersion mixers allowed, or I’ll end up with a beaker full of air bubbles!

  • Phase C (The Trigger): This is my favorite part. When I add the Betaine and the pH adjusters at the end, I often see the “thickening moment” happen right before my eyes.

Final Lab Thought

Formulating detergents is a game of patience. If I rush the mixing, I lose the clarity. A thin gel still cleans, but I’ve found that a thick, glossy gel is what makes the experience feel truly professional. It’s all in my hands! 😉

HAVE A GREAT DAY! 😄

52 thoughts on “How to formulate a detergent – THEORY pt.2”

  1. Pingback: On Surfactants and Formulation (face wash, shampoo and shower gels) | It's all in my hands
  2. Pingback: How to formulate a Face Wash – with Recipe | It's all in my hands
  3. Pingback: How to formulate a detergent – THEORY pt. 1 | It's all in my hands

  4. Thank you for all this research and information !
    I was wandering is one can use baking soda (sodium hydrogen carbonate, NAHCO3) as an amphoteric surfactant ?
    In that case, if I have pure sodium hydrogen carbonate, all of it would be active surfactant matter, wouldn’t it ?

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  5. Hi I was wondering what using boiled soap nuts would be considered. Or would it be able to replace one of the surfactants?

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    1. I am not a big fan of soap nuts to be honest.
      Yes they seem to produce something like a surfactant but you cannot know the concentration and the “washing ability” and so on. So this is already a big problem for formulating because in order to formulate a good detergent, you need these infos.
      Also, there will be another problem when talking about preserving the detergent: if you boil these nuts, you are actually going to have a lot of organic matter to deal with in your solution. Organic matter means good food for bacteria… which leads to infested detergent.
      You might end up needing to use a very high % of preservative, de facto spoiling your intention of having a “more natural” detergent.

      Thing is: there are many many many surfactants that you can purchase online which are certified to be of natural origin, work much better than soap nuts, have better qualities (like wetting ability for example), you know what you are using… and so on.
      So, sorry, but I don’t suggest to use soap nuts 😀

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  6. First off I love your site and your YouTube channel…Secondly what If i don’t want to add cocamidoprpyl betaine in my detergent…I’m not really interested in the lather just the cleaning ability. Will leaving that out alter the consistency or effectiveness of the detergent?

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  8. HELLO
    I WANT JAUST THANK YOU FOR YOUR INFORMATION ,an d i have one quation about the paste dish wishing if you have any idea N???

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    1. I don’t know what is “paste dish wishing” but if it is (I guess) some detergent for washing the dishes, I can say nothing because I have only formulated cosmetics and not products for cleaning the household and so on. I really don’t know anything about that.

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    1. Yes you can: SLES is anionic, CAPB is amphoteric and this is a very common combination!
      It is anionic and cationic that usually aren’t mixed, and it is basically because of their opposed charge.

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      1. Main characteristic of amphoteric surfactants is their dependence on the pH of the solution in which they are dissolved.
        In acid solution the molecule acquires a positive charge and behaves like a cationic surfactant. In alkaline solution they become negatively charged and behave like an anionic surfactant.

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  11. How to use polyacrylamide in thickening dish soap without the unpleasent stringing

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  12. Hi,thancs for this useful article.
    I have some questions.First, why does adding secondary surfactant decrease viscosity especialy when we use a polymer thikener,and may the salt to harm to another indregents ,for example chlorhexidine?

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    1. Hei Miroslav, I am not sure I understood: in the article I state that adding a secondary surfactant sometimes increases the viscosity (but it depends on the surfactants). If you add a thickener, that would increase the viscosity as well but, of course, it depends on the polymer: carbopol ultrez 21 hate salts so it wouldn’t work. But if you add a polymer which is made for working with surfactants, then it obviously works.
      Surfactants and polymers are such a wide category that it is impossible to generally speak about them 🙂

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      1. Hi,Sorry I didn’t explain well.
        I make viskosity solution by mixing “Ammonyx MO” (myristyl dimethyl amine oxide) that’s my primary surfactant and Cocobetain my secondary one.In the end I add thikener “Glukamat LM” (methyl glucose ether).When I put those indregents in this order 1Ammonyx;2 Betain; 3 Thikener, I have viskosity liquid soap,but when I change the order and put first betain the viskosity doesn’t increase after puting the thikener.

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      2. Yes, it can happen. That’s why I tend to add betaine at the end: sometimes it does work like this with surfactants and you need to add ingredients in a specific order.
        I have never used that primary surfactant nor this specific thickener, so I cannot know for sure, but have you checked the instructions of the thickener? Cause they might request for it to be added at the beginning, to water alone! This is the case for Carbopol Aqua, for example: it must be added at the very beginning or it doesn’t thicken at all.

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  13. Hi! Thank you for your very good article! 🙂
    I just like to ask about “sodium lauroyl sarcosinate + pH 5”, at which phase can I add citric acid? Is it at the start along Phase A? or during Phase C?

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      1. Hello, my name is TANESHA, i really need your help in this natural anti-dandruff shampoo formulation. The thickener i used in this formulation is sodium cmc of 1.3 % by weight. After 6 months, the shampoo became unstable as it is natural thickener, it became more thicker than it should be. now, what can i do to stabilize the shampoo? please help. This is natural shampoo, thus i cant add synthetic ingredients.
        The shampoo formulation in (%by weight) that i used is:
        Antibacterial agent: 0.5 %
        EDTA : 0.5 %
        Tween 80 : 20 %
        Sodium Benzoate : 0.1 %
        Sodium CMC : 1.3 %
        Citric Acid : As needed
        Water : Qs – 100.
        Thank you very much for your time and consideration.

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      2. Hi Tanesha.
        Under what certification is Tween 80 considered “natural”?

        What is the antibacterial agent you used?
        I have never used CMC, I don’t know if after few months it gives this kind of issue.
        However, this shampoo doesn’t look like a good formula to me.
        There are many better natural-certified surfactants that could be used in combination.
        I don’t think the “being too thick” is the only issue of this formula.

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      3. Can we use Labsa + sles + Capb based theory for making detergent liquid?

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  14. Hi and thanks for making surfactants more understandable.

    I would like to make shampoo and a creamy foaming facial cleanser. I purchased some SLSA and coco betaine but realise I need to add one extra surfactant (at least).

    Could you suggested what might be a basic kit of surfactants that I need to develop skills in formulating detergents for skin and hair? I am a little overwhelmed by the number that are available. I am keen to learn how to calculate and use surfactants but need to get the basic ingredients first.

    Many thanks.

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    1. You don’t “need” the contour surfactants. They just help in modulating the strength and so on, but you can also add a 1% of oil for example (there is a risk it separates, so add it to the mix of surfactants first and then add the water).
      SLSA I guess is in powder form? Cause that will take heat
      If you buy liquid surfactants it gets even more simple as they mix quite easily.
      This said, a basic kit with SLES, coco betaine and a glucoside is usually a normal starting point. It could be Decyl glucoside, Lauryl glucoside (needs a little heating) or Coco glucoside…
      Surfactants are quite fun and you rarely can do something really “wrong”. It just depends what you want to get and that may take some time to find out how to do but you’ll get there with enough trial and error 🙂

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  15. Hi thank you for your article it helps a lot,

    I just want to ask if banana peels is a good surfactants?

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  16. Hi, which is the most mildest and effective surfactant. I found non ionic like coco glucoside etc are milder and of more natural origin. Can I use only this in my solid shampoo bar with btms. 50. Regarding preservative is grapefruit extract good enough. And can I add xantham gum powder or liquid for thickening. Also any other natural ingredients like henna, shikakai. And can it be made without heating like i have seen videos where people make without heating just mixing and pressing or mixing and freezing.

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    1. Check my formula for the shampoo bar. You can use the coco glucoside but just that will make your “bar” liquid. Check my formula for a better understanding of how to formulate a shampoo bar. 🙂
      Grapefruit extract is not a real preservative.

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  18. Hi,
    Would this make a decent shampoo
    Sles 20%
    Capb 15
    Poly quat-7 @3%
    Glycerin 2/3%
    Rest water …
    Is there a need to add any detangler or more emollient after adding above ?
    Would highly appreciate your input..

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    1. It all depends on your hair type. Pq7 3% seems high to me but maybe it is good for your hair.
      Try the formula, make a small batch (100 grams) and see if you need to tweak the formula for your hair!
      Ps. Don’t forget preserving it 😉

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      1. Thank you for responding. I have dry and fine hair.. I’m aiming this to be for people with hair like me, like a Moisturising – Detangling Shampoo…
        I can start with Polyquat 7 @2% , and then if need be 3 .
        Should I add EDTA/ Sodium Gluconate … I have hard water where I live.

        Many thanks for clearing up my queries in advance.

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  19. Thank you for this explanation on shampoos/detergents. I’ve paid for cosmetic classes, the swiftymonkey blog, i’m in makingskincare groups on fb, read published articles from chemists and no one has made as much sense as you have here. Like i swear, a freakin’ light bulb has turned on and i’m just so freakin’ thankful because shampoo is my last item to make and it’s been so so so hard.

    and then lastly, this post is like from what? 2015? that makes it old but look! it’s still got some really good information, info that’s still relevant! everyone raves about this swiftymonkey blog that you gotta pay for but everything is old, outdated, broken. i ask a question and get pointed to an old outdated article and have more questions because info isn’t relevant and the creator is grumpy (tbh, they are rude) with their replies even though my journey on their blog is a course set by them! the people above me are asking questions you’re answering them and you’re being nice and polite and it’s like you know we are clueless newbies desperate for learnin’ and we just need a push in the right direction.

    So thank you for your blog with fantastic information.
    thank you for being nice
    thank you for answer our questions
    thank you for having this blog and i’m sorry i didn’t find it sooner.

    you’re the hero we didn’t know we needed

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  20. This is great. But I need more help. I want to make a drying shampoo (I know weird right?) but I want to use decyl glycoside and lauryl glycoside, beer, sea salt and distilled water. Could you help give me an idea of what amounts to start with? I can change it later but I just for the life of me can’t figure out where to start.

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    1. I would definitely NOT use any beer at all as it would be impossible to preserve the shampoo.
      Adding too much salt will destabilize the shampoo, add a little (0.1 g) at a time and see if the consistency of the shampoo changes… it will probably thicken up to a certain point… and then it will start thinning.
      When it start becoming less viscous, stop adding the salt.
      About decyl and lauryl glucosides, you can follow the guidelines of how to formulate with surfactants.
      Good luck!

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      1. Thank you. I read the page about formulating surfactants twice. But I couldn’t figure out how to formulate those 2 together.

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  21. Thank you very much for the information you have shared. I have a few questions, I hope you won’t mind to consider.

    What do you think of combining an anionic with a non-ionic? (I have coco-glucoside [non-ionic] and sodium cocoyl glycinate [anionic]). Would this make an irritating combination?

    Also, how essential is glycerin to the formula? And does the inclusion of glycerin reduce the irritancy potential of the surfactants at all?

    Last question: is there a certain ratio, between one surfactant to another, that should be considered? Or can you add any ratio as long as the total ASM is within the recommend range for the type of product being made? For example, could I use a 1:1 ratio (2% of one surfactant, 2% of the other)? Or is a different balance (ratio) preferred? I hope that question makes sense.

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    1. Hi Megan,
      You can definitely use those together.
      Irritability depends on many things.
      Glycerin is not essential but I would advise at least a 0.5%. It lowers irritability slightly.
      The ratios you are talking about are “suggested” by producers usually, because they have tried many different ratios and they have found a certain ratio between two or three surfactants to bring the best results (for example SLES and CAPB)… so the best thing you can do, if you haven’t find commercial formulas with the two surfactants you want to use, is to try different ratios in small batches and see which combination you like the most.
      Of course changing the ratio changes the end result 🙂

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  22. Hi – this has been such a great read – I came via soap makers forum!

    I’ve been experimenting with creating a solid shampoo bar using SCI and Decyl Glucoside. I understand the theory for using multiple surfactants to create a milder bar but it is being formulated for extremely sensitive skin so these two seem to get the best reviews. ( I looked at adding Cocamidopropyl betaine but read that this can be something of an irritant to some people so decided on leaving it out) Is two okay?

    Additionally having experimented with formulas I’ve been using 65% SCI and 15% DG to get to a total surfactant percentage of 80% – this seems to work well but is there any issue in using SCI in such a high percentage?

    Thanks in advance!

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