I have been using Polysorbate 80 for years. P80 is a fatty acid ester. It is used as an emulsifier in many food products and as a delivery vehicle and/or additive in many hair products. I think that it is good, beneficial stuff. And, it is VERY inexpensive. I believe that with all the new stuff, it has been cast aside and classified as useless by many. I think they are missing out on a good addition to their regimens.
It works, I believe in several ways.....................plain P80 when rubbed into the scalp vigorously causes the scalp to become red and a bit warm. I believe it encourages hair to grow by causing the scalp skin to release histamine, by deep cleaning the follicles and by possibly interfering with DHT on the follicles.
It defenitely loosens hair that was going to fall out anyway when you start using it. Probably the best "deep down" scalp cleaner I have found to date. I even used to rub it on my face when I had acne years ago and I believe it helped with that as well.