I've tried them and had no results at all. i know you said no heat, but thats what I've had best results with. (my hair is annoyingly deep and wavy) i just use a good heat treatment spray and GOOD flat iron (i use a T3 tourmaline, works AMAZINGLY) and i also bend over and flip my hair down (hanging towards my feet) when i straighten it and it gives it more volume :)
Nothing ever worked for me except the keratine hair treatment. It's expensive but more than worth your money. I had very curly & dry hair, now it's been a year since I've had it & my hair is still completely different. Stays straight all day, not as curly. It was very straight for 6 months & starting wearing out. But even still. 10x easier to manage even still. Plus, my hair started growing so fast after, & still is!
The only thing aside from a flat iron that works is getting your hair chemically straightened. It isn't permanent so you would have to do it again. The shampoos only help for those who do use flat irons.