Type 4 hair is the tightest curl pattern and has “S” shaped or zig-zag curls that are very tightly coiled. Since this hair type is so tightly coiled, it’s known to shrink up to 50% of the actual hair strand’s length. It also has fewer cuticle layers than any other hair type. This means that it has less natural protection from damage inflicted by combing, brushing, curling, blow-drying or straightening, so it’s important to find the right products.