Each hair strand that grows for up to three years and absorbs metals that slowly builds up.
The study by the P and G found that it can break down the sheath of the strand, leaving it susceptible to sunlight and chemicals that damage hair, the Daily Express reported.
The study also found that the effects are a lot more severe for people who use dyes.
Dr Jennifer March, study leader from pharmaceutical giants Procter and Gamble, said that copper comes from the tap water and the hair acting like a sponge picks it up over time.
The findings have been published in the International Journal of Cosmetic Science.