Home Cosmetic Science Talk Formulating How to calculate ASM when making a shampoo/bodywash, etc.?

• How to calculate ASM when making a shampoo/bodywash, etc.?

Posted by on April 23, 2024 at 9:10 am

Hi,

I’ve been formulating for few months now (so still new to this), and I just want to double check that I’m calculating the ASM correctly (something inside of me tells me I might be doing it wrong). The way I’ve been doing it is like this:

Say I want to use SCI (85% active) as my primary surfactant and Disodium cocoamphoacetate (30% active) as my co-surfactant, and I want my ASM to be 12%. I’d assign 8% to SCI and 4% to Disodium cocoamphoacetate. The way I’d calculate it is this way:

1. 8/0.85= 9.41g

2. 4/0.3= 13.33g

I do this regardless the batch size is 100g or 250g. That’s what’s been in my mind if this calculation won’t work on all Batch sizes. So I’m I doing it right or it should be done differently?

2 Members · 2 Replies
• 2 Replies
• Perry44

April 23, 2024 at 9:41 am

You’re almost right! You’ve calculated correctly the amount need for 100g. If you want to make a 250g batch then you’ll need to multiply those numbers by 250/100 = 2.5.

SCI: 9.41g x 2.5 = 23.53g

Disodium cocoamphoacetate: 13.33g x 2.5 = 33.33g

Or if you wanted to make a 500g batch you would multiply those numbers by 500/100 = 5.

• Heath0o7

Member
April 23, 2024 at 10:03 am

Thank you so much! I appreciate it! You gotta trust your gut lol

One other thing that I’d love to learn is once you’ve decided what your ASM will be, how do you assign it to your surfactants? Is there a ratio to follow?

Also, I’ve been getting conflicting answer about this, should a hand wash ASM range be 10% - 15% or below 10% like a face wash?