What is sodium lauryl sulfate and is it safe to use

If you’ve ever studied the causes of a skin complaint or damaged hair, chances are someone on the internet has pointed the finger at SLS, or sodium lauryl (or laureth) sulfate, a common ingredient in beauty products, washes, toothpastes and even cleaning products.So what does this ingredient do, why is it in everything, and what does the evidence say about how safe it is?