Surfactants and their ASM value are among the terms you need to know when making natural cosmetics. When choosing surfactants for your product, it is not only their charge or their foaming and cleansing properties that play a role, but above all ASM — that is, how much active substance will actually be present in your product. Thanks to knowing the ASM value of your surfactant combination, you will be able to dose surfactants more effectively, avoid wasting them, or avoid skin irritation caused by an excessively high dose of surfactants.
About this article
This article explains the term ASM — the value that represents, in per cent, how much active substance is actually present in the product. In it you will find the most commonly used ranges of total ASM values for individual groups of products, a list of the most commonly used surfactants and their ASM values, and also two methods of calculating the total ASM value of your product. It comes in handy for anyone formulating their own shower gels, shampoos, facial cleansing foams or bath foams.
Why you should know the ASM value
- More effective dosing
Thanks to knowing the ASM value of your surfactant combination, you will be able to dose surfactants more effectively.
- No wasted raw materials
Verifying the total ASM value of the surfactants used will help you avoid wasting them.
- Gentle on the skin
You will prevent skin irritation caused by too high a concentration of surfactants in the product.
- A check on recipes taken from elsewhere
When formulating a recipe or taking it over from various sources, you can verify the total ASM value by calculating it.
- Freedom in combinations
You can reach the same total ASM value with different ratios of the individual surfactants — depending on what you have to hand.
ASM in brief
What is ASM?
ASM is the English abbreviation for active surface matter. ASM is used mainly with surfactants and this value, expressed in per cent, represents how much active substance is actually present in the product. It is good to know the ASM value of a surfactant precisely because surfactants are not sold as 100 % pure substances. This means that every surfactant, in addition to the cleansing substance (its share is expressed by the ASM value), contains other compounds, most often water, possibly glycerin or components adjusting the pH, and similar.
For this reason as well, when dosing a surfactant into your product, a 30 % share of surfactant in the product does not mean that there will actually be 30 % active substance in the product. On the contrary, there will be less, because the added surfactant is already diluted.
A similar situation applies, for example, when using solutions of certain substances or acids — lactic acid, for instance, is sold as an 80 % solution, so if you want to have 1 % pure lactic acid in 100 g of product, you must add more than 1 gram, since it is already diluted.
ASM of products
If you want to formulate a product with several surfactants in a blend, you always take into account the total ASM value that these surfactants will have together. At the same time, it holds that you can mix the individual surfactants in different ratios in order to achieve the given total ASM value. For example, you can use a surfactant with a higher ASM value in a smaller amount and, conversely, increase the share of a surfactant with a lower ASM. Or, if you want to save on the amount of raw materials, you can use only a surfactant with a higher ASM value (of course, within the dosage range recommended for the given product).
What total ASM value, however, should your product have? Below you will find the most commonly used ranges of total ASM values for individual groups of products.
| Product group | Total ASM value |
|---|---|
| Shower gels | 15 – 20 % |
| Facial cleansing foams/gels | < 10 % |
| Shampoos | 10 – 15 % |
| Bath foam | 20 – 25 % |
Where can I find the ASM value of surfactants?
The ASM values of surfactants are measured and provided directly by the manufacturer. When purchasing raw materials, you will find them listed in the Certificate of Analysis that accompanies each raw material. Sometimes it happens that ASM is not given as an exact value, but as a range — in that case you can take the mean value of this range into account in your calculation, or look more closely at the Certificate of Analysis, where you usually find the exact value measured for the given batch. Precisely because of individual differences between batches and the quality of raw materials from various sources, the ASM value of a surfactant can change, and that is why it is given as a range of values.
For better orientation among surfactants, below you will find a list of the most commonly used surfactants and their ASM values.
| Surfactant | ASM value |
|---|---|
| Caprylyl/capryl glucoside | 63 % |
| Cocamidopropyl betaine | 37 – 42 % |
| Proteol apple | 30 % |
| Coco glucoside | 51 – 53 % |
| Decyl glucoside | 51 – 55 % |
| Disodium cocoyl glutamate | 30 – 31 % |
| Lamesoft PO | 50 – 55 % |
| Lauryl glucoside | 50 – 52 % |
A closer look at the surfactants from the list
From the list of the most commonly used surfactants above we have picked four — two of them also feature in the calculation examples below.
Caprylyl/capryl glucoside
Caprylyl/capryl glucoside has the highest ASM value listed — 63 %. This means that you will reach the same total ASM value with a smaller amount of it than with surfactants that have a lower ASM.
Cocamidopropyl betaine
Cocamidopropyl betaine has its ASM value given as a range, 37 – 42 %. In both calculation examples below we work with a value of 38 %.
Proteol apple
Proteol apple has an ASM value of 30 % — given as an exact figure, not as a range. It is the second surfactant in our facial cleansing foam examples.
Decyl glucoside
Decyl glucoside has an ASM value of 51 – 55 %. Similarly high values are found in coco glucoside (51 – 53 %) and lauryl glucoside (50 – 52 %).
How to calculate the ASM value of the product?
When formulating a recipe or taking it over from various sources, it is good to verify the total ASM value of the surfactants used. This is also so that you do not needlessly waste raw materials, or to avoid potential skin irritation due to too high a surfactant concentration.
ASM calculators
For the calculation you can use online calculators, where you enter the ASM value (in per cent) of the given surfactant (provided by the manufacturer in the Certificate of Analysis) and the amount of the given surfactant in the product that you desire. The calculator automatically calculates what the ASM value of the surfactant in the product will be. Subsequently, you can adjust the share of the individual surfactants in the product until the ASM value of the surfactants in the product suits you.
The advantage is that the calculators work for several surfactants simultaneously. The disadvantage is that they are mostly available in English, but with the use of online translators their use can be managed.
ASM calculation step by step
There are two methods of calculation by which you can arrive at the total ASM value of your product. We will present both calculations using the example of a facial cleansing foam containing two surfactants, namely Proteol apple (ASM 30 %) and Cocamidopropyl betaine (ASM 38 %).
Calculation using predetermined ASM values
- Determine the total ASM value 7.3 % ASM
First we determine what total ASM value of surfactants we want — in our case this can be 7.3 % (1.5 + 5.7).
- Divide the ASM between the surfactants
Subsequently, we determine what share each surfactant will have in the total ASM: Proteol apple 1.5 % ASM concentration and Cocamidopropyl betaine 5.7 % ASM concentration.
- Convert to the actual share
Then we need to calculate the actual percentage representation of the given surfactant in the product, i.e. the figure that you find in recipes and that corresponds to the actual added amount of surfactant. We arrive at this value by dividing the ASM concentration of the given surfactant in the product that we have determined by its ASM value given by the manufacturer, and multiplying the whole by 100.
- Result 5 % + 15 %
Proteol apple 5 % ((1.5/30).100 = 5 %) and Cocamidopropyl betaine 15 % ((5.7/38).100 = 15 %). Thus, 5 % Proteol apple and 15 % Cocamidopropyl betaine will be added to the product.
Calculation using predetermined surfactant values in the product
The second method works on a similar principle to ASM calculators. We determine in advance what actual share the individual surfactants should represent in the product. Subsequently, we calculate backwards what their ASM value in the product will be. If this value is too high or too low, the actual share of surfactants in the product is adjusted and the recipe is recalculated.
- Determine the share of surfactants in the product 10 % + 10 %
For example, we want a facial cleansing foam in which the surfactants are used in the following percentage shares: Proteol apple 10 % and Cocamidopropyl betaine 10 %.
- Calculate the ASM concentration
We then calculate what ASM concentration in the product corresponds to the given amount of surfactants — by multiplying the ASM value of the surfactant provided by the manufacturer by the share of surfactant in the product that we have chosen, and dividing everything by 100. Proteol apple 3 % ASM concentration ((30.10)/100 = 3 %), Cocamidopropyl betaine 3.8 % ASM concentration ((38.10)/100 = 3.8 %).
- Add up the total ASM 6.8 % ASM
Total ASM: 3 + 3.8 = 6.8 % ASM concentration. A value of 6.8 % total active surfactant in the product is sufficient for a facial cleansing foam.
- Recalculate if necessary
If you want to change this value, the representation of the individual surfactants in the product has to change and the recipe has to be recalculated. Precisely for this reason, if you choose this procedure, ASM calculators are advantageous — they perform the calculation for you and you only change the actual representation of surfactants in the product.
Common questions about surfactants and ASM
Practical questions about the ASM value — what it means, where to find it and how to calculate with it.
What does the abbreviation ASM mean?
ASM is the English abbreviation for active surface matter. This value, expressed in per cent, represents how much active substance is actually present in the product.
Why does 30 % of surfactant in the product not mean 30 % of active substance?
Because the added surfactant is already diluted — surfactants are not sold as 100 % pure substances. In addition to the cleansing substance they contain other compounds, most often water, possibly glycerin or components adjusting the pH.
Where can I find the ASM value of a particular surfactant?
ASM values are measured and provided directly by the manufacturer. When purchasing raw materials, you will find them listed in the Certificate of Analysis that accompanies each raw material.
What should I do if the ASM is given as a range?
In that case you can take the mean value of this range into account in your calculation, or look more closely at the Certificate of Analysis, where you usually find the exact value measured for the given batch. The range is given because of individual differences between batches and the quality of raw materials from various sources.
What total ASM value should my product have?
The most commonly used ranges are: shower gels 15 – 20 %, facial cleansing foams/gels < 10 %, shampoos 10 – 15 % and bath foam 20 – 25 %.
Can the same total ASM be reached with different ratios of surfactants?
Yes. You can mix the individual surfactants in different ratios — for example, use a surfactant with a higher ASM value in a smaller amount and increase the share of a surfactant with a lower ASM. Always, however, within the dosage range recommended for the given product.
Surfactants and their ASM value — conclusion
Some terms need to be known when creating natural cosmetics so that you can always create a product without any imperfections. We believe that this post has contributed to that as well.
We will be happy to answer all your possible questions, feel free to write to us at [email protected].
Until saponification, friends.
Glucosides, betaines and powdered surfactants with their ASM values listed can be found in the Handymade raw material range.
