Dull hair is often caused by Product Build-up. This is the gunk and residue left by your hair care products. Build-up keeps much needed moisture from penetrating your hair. Your hair will be dull, lifeless, and you will not get the results you want.

You can use a clarifying treatment like apple cider vinegar to remedy this. Periodically clarifying your hair is a MUST. Also, make sure you deep condition your hair on a regular basis, too.