With a pH of 9.5 to 11, it is very alkaline and we have to get the pH down by the inclusion of citric acid. The suggested us it 1% to 10%, depending upon the surfactant mix. You want to use this at a 4:1 ratio with 4 parts surfactant mix to 1 part cocamide DEA. It doesn't react to salts, so you can't thicken it that way, but you probably won't want to when you see the thickening power of this surfactant!
I use this in my bubble baths all the time - I find the 4:1 ratio a little high. Anything over about 5% will feel a bit sticky and too greasy and will make your bubble bath thicken too much. I like to use in body washes around 2% to offer a "greasy, slippery feel" to the foam and a moisturized after feel. If you use it at low levels like these, you don't really need to worry about the pH as the other surfactants and ingredients will ensure it stays at a nice level, like 6.0.
You may also find diethanolamines derived from lauric acid (lauramide DEA) and oleic acid (oleamide DEA).
Cocamide DEA is mild on our skin, but can cause skin irritation at 10% in a leave on product for some people. As with any ingredient, try it and see what your body thinks!
If you do a search for cocamide DEA, you might come to think it is the devil itself. I've seen sites stating it can cause cancer, but I haven't seen reputable studies to back up this concern. The CIR expert panel determined it is safe at 10% or lower in rinse off products and safe in rinse off products (click here for more information). A 2 year study on rats showed there was no increase in rats who were given DEA, although there was some irritation of the skin (but remember they are using really high levels of this stuff - not 4% in a bubble bath!). As with any ingredient, make your choice to use or not use it based on facts and not myths.
I know there will be posts telling me I'm wrong - I can accept that, but only if you can back it up with information from reputable sites or studies.
Join me tomorrow for ideas on incorporating mildness into your surfactant creations.