Tuesday, August 18, 2009

The soaping effect (insert dramatic chord here).

I've had two comments this week asking about the soaping effect and how to prevent it...so let's take a quick look at it!

The soaping effect is defined as "an undesired foaming phenomenon observed in skin creams formulated with soap based emulsifiers". You may have noticed this in your lotions - the white streaks when you rub the lotion on and a slight tacky feeling on your skin.

Why does this happen? It's saponification!

The fatty acids in the lotion, combined with an alkaline ingredient like triethanolamine or potassium hydroxide, create a soap, which acts as the emulsifier in your lotion. (A common combination is triethanolamine and stearic acid.) If you're using a stearate or oleate based emulsifier, you are bringing the water and oil together in your lotion by creating a soap, which is going to leave those white streaks when you apply it.

What can stop the dreading soaping effect?
  • Adding dimethicone at 2 to 3%.
  • Using a non-ionic emulsifier like Polawax or emulsifying wax NF.
  • Using a cationic emulsifier like BTMS.
If you don't want to use silicones, then your only option is to change emulsifiers and see if that helps.


Anonymous said...

oh dear used BTMS with cetyl. The Cetyl seems to be the problem ingredient. Do you think adding C12-15 Alkyl Benzoate would help?

Bob said...

Olivem 1000 -> no soaping
Olivem 1000 + xantham gum -> soaping

Welly said...

I use ecomulse and still have that effect a bit? Any suggestion?

Susan Barclay-Nichols said...

Hi Welly. Did you try the suggestions in the post?

Elizabeth Aqui-Seto said...

Susan, I need your help with this soaping effect. Is Aloe Vera gel/juice considered an alkaline ingredient?

As a rule, I substitute the water ingredient in most of your recipes for aloe vera. If we take an example of the basic lotion, I'll often use 66% aloe vera juice or gel. And I use all the other ingredients in the recipes, so no other substitutions.

Could the aloe vera substitution for the water, produce the soaping effect?

Susan Barclay-Nichols said...

Hi Elisabeth. I don't think so. It has a pH of 5 to 6, so it must be another ingredient in your lotion. What emulsifier are you using?

Ash Sarsakht said...

Hi Susan,

Thank you for your email. as you suggested here is my recipe that I used and still get white residue. ( soap effect)

water : 50%
aloe vera juice: 21%
glycerin :2.5%
allantion: 0.5%

apricot oil: 6%
macadamia oil: 6%
jojoba : 3%
polawax: 5%
cetyl alcohol: 3%

germul plus : 0.5%
silk amino acid: 0.5% ( it is powder)
vitamin E: 1%
honeyquat : 1%

Thank you very much and have a great day,