Although all my shampoos are sulfate free, there's no need to worry about not getting a great lather. Yes, they will lather less than shampoos with sulfates, but I've picked out the best natural ingredients that are known to lather up nicely. But with that being said, did you know that you can get a lot more lather if you wash your hair twice? If you've worked in the food industry and come home with hair smelling like a deep fryer, you know about lathering up twice! The reason that shampoos lather up better the second time is that the first wash cleans away any "anti-foamers" like dirt and excess oil that stop the shampoo from lathering up as much. So, when you shampoo again, you get a lot more lather than the first time because there's nothing in your hair to stop the lather from foaming up!
But is shampooing twice bad for your hair? It depends. It depends on the type of shampoo you're using. If you're using a shampoo that's damaging your hair by drying it out with harsh detergents, than yes, shampooing twice would be bad for your hair (as would the first time!). But if you're using a mild formula, there's no reason why you can't lather up twice. Just be aware that you might need more conditioner :)