The lipid layer of your hair is what protects your hair against humidity and water damage.
Chlorine can effect it, but so can RAW oils.
Oils (like from the kitchen section) contain a lactic acid (or similar compound) that can eat at the protective lipid layer of the hair in large doses (like when it's not formulated into product)
RAW oils also have a boiling point typically around the temperatures we're seeing outside this time of year, and can add heat damage to that mix.