Liquid always cause me pain as a backpacker. A litre of shampoo, a litre of conditioner, and a litre of body wash are minum if you don't pack another litre of lotion with you. That's is 3 KG right there.
You got to check out the solid bar of shampoo, conditioner and lotion at LUSH~!
Amazing if you plan to back lite and eliminate the chance of spilling slimy liquid in your backpack.