Home Cosmetic Science Talk Formulating Hair Is it weight percentage or mole percentage in a formula that matters most?

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• Is it weight percentage or mole percentage in a formula that matters most?

Posted by on February 20, 2023 at 3:46 am

I am trying to make a Shampoo formula from a patent.

The formula in patent has

Active surfactants

SLE3S 12.5%

SLS 1.5%

CAPB 1.5 %

As I don’t have SLE3S i want to use SLE2S instead of it.

I want my formula to be as close to that original as possible.

Now when i replace SLE3S by SLE2S, should i replace it by equal weight percentage and use 12.5% SLE2S or with equal mole percentage which is 11.19% SLE2S by weight?

Or should i ask, is it the weight percentage or mole percentage that matters most?

Molecular weight of SLE2S 376.4861

Molecular weight of SLE3S 420.54

replied 1 year, 6 months ago 5 Members · 7 Replies
• 7 Replies
• ChloeCosmeticChemist

Member
February 27, 2023 at 8:05 pm

Cosmetic formulas are written as weight percents, so I would suggest to use the weight percents from the Patent and swap the identity of the ingredient.

• Pharma

Member
February 27, 2023 at 11:43 pm

From a purely scientific point of view, mol-% would be used in case of surfactants and solubility. For certain values/characteristics of cosmetics or their ingredients, weight or volume matters instead; so don’t just assume that science = mol ????.

• Abdullah

Member
February 28, 2023 at 4:52 am

Thanks a lot

• hassanizhar

Member
February 28, 2023 at 5:45 am

When replacing SLE3S with SLE2S in a formula, it’s important to consider the composition of the original formula and the intended outcome of the replacement. Both weight percentage and mole percentage can be used to express the composition of a formula, but they represent different quantities.

Weight percentage (wt%) expresses the weight of a substance as a percentage of the total weight of the formula, while mole percentage (mol%) expresses the number of moles of a substance as a percentage of the total number of moles in the formula.

• MarkBroussard

Member
February 28, 2023 at 8:03 am

In cosmetics, I don’t think it really matters much either way since the objective is for the ingredients to not chemically react. A consumer will not notice the difference between 12.5% or 11.19% SLES in a formula.

• Pharma

Member
February 28, 2023 at 2:20 pm

True. Although the molecules (usually and hopefully) don’t react, they still interact with each other. Sometimes, there can be quite a difference depending on what you calculate/create. But then again, cosmetic ingredients are often not really pure and the margins of error fairly large…

• Abdullah

Member
February 28, 2023 at 8:51 pm

You are correct. No big difference on those two percentages.

My point was about the synergy that it has with for example CAPB. That patent was from p&g and i am sure they have checked that at what ratio it provides best synergy.

These percentages are not much different but they my not have they same synergy with CAPB and that make the difference a bit bigger. Or maybe not ????