The outer layer of each strand of hair is made up of small cuticle scales. They overlap for protection of the hair shaft, laying flat and reflecting the light to give shine.
Rather like louvre blinds, these cuticles open when the hair is washed. When this layer of protective scales is damaged, the cuticles don't close properly, causing an uneven sheath. The hair looks course, tangles frequently and breaks with ease. Instead of reflecting the light, the hair absorbs it taking on a dull and lifeless appearance.
The residue left behind from many of today's hair products builds up on the hair shaft. This residue coats the strands, and impedes the cuticle's ability to lay flat. Rinsing the hair with cider vinegar helps to condition the scalp, removes residual build up, and promotes closing of the cuticle layer. Tangles are fewer because the strands of hair are smooth, and natural shine is restored.