Most of the store - bought regular shampoo should have produced lots of foam once you started shaking it. (scientificamerican.com)
For example the ability to create lots of foam and control its stability is important because people associate more foam with more cleaning power. (scientificamerican.com)
You may be tempted to just add everything to the blender, but unfortunately that just makes a whole lot of foam. (wellnessmama.com)