Why does Glycerin reduce viscosity of shampoos?Hi everybody,After read many comment in forum about glycerin reduce viscosity of surfactant based product, I want to find out more details about this. Is that effect only in glycerin or other polyols (eg: propylene glycol, polyethylene glycol.. ) and at what concentration does this happen?Thank you in advance!P/s: Another question xD. How to add conditioning agent in shampoo? I use Amodimethicone (and) Trideceth-10 and Dimethiconol (and) TEA-Dodecylbenzenesulfonate (and) Trideceth-10. Disperse in water or add directly after combine surfactant and thickening agent (SLES/CAPB and PEG-150 distearate, salt) ?