What’s so bad about shampoo anyway?
Shampoo is a detergent, just like laundry detergent, dishwashing powder and the stuff you use to clean your bathroom. It cleans out the dirt in your hair, but is very harsh and also takes the natural oils that make your hair shiny, soft and strong. Shampoo wasn’t introduced until the early 20th century, before that many people used soap. Soap can wash your hair without removing as much of the natural oils that shampoo does. Unfortunately, it doesn’t stand very well in alkaline water.
When mineral levels in water began to rise, that made soap a messy, poor item to wash with. It causes ‘soap scum’ rings around your tub and on your shower doors. Alkali (hard water) makes the scales on your hair stand up, feel rough and get tangled. When washing with water with a higher alkaline content and soap, the “soap scum” gets all tangled up in your hair, is much harder to wash out, and creates a big mess. Shampoo came out on the market just in time, displaying it’s only real benefit: it behaves similarly both in hard and soft water. Therefore it was a “Superior” product to an old favorite, soap. But it didn’t come without problems. Because shampoo is harsh enough to strip the natural oils from your hair, you need something to replenish them. So, conditioner was born. You need to wash your hair every day not because it gets dirty, but because the oils from the conditioner don’t last and need to be replenished.
The oils in your hair come naturally out of your scalp to nourish it. Stripping them away causes damage, and breakage over time. In a way you do need conditioner, if you use shampoo – because it covers up the damage that’s been done. But you don’t need shampoo in the first place, all you’re spending your money on is a big bottle of perfumed detergent.
Most shampoos contain mineral oil. A byproduct of the distillation of gasoline from crude oil, mineral oil is what’s left over. It’s so abundant that it costs more to dispose of it then it does to package and sell it, so it ends up everywhere. It’s added to shampoos and conditioners to give hair an artificial shine caused by coating it with a thick oil. Mineral oil cannot absorb into your skin like other oils do, so it sits on top and forms a barrier preventing oils and toxins from being released as a normal part of your skin’s lifecycle. This is one of the reasons you’ll find that the more shampoo you use, the more often you need to use it. In the long run, coating your hair with mineral oil makes it weaker, and more prone to damage. 
If mineral oil doesn’t bother you, maybe the other ingredients will. SLS and SLFS (sodium lauryl sulfate, sodium laureth sulfate) are skin and eye irritants that also acts as a foaming agent in soaps, shampoos, toothpastes, dishwashing liquid… and just about anything that produces a foamy lather.