Hair greying is a longer, irreversible process that can start at different ages. It is influenced by many factors, such as stress, abuse of alcohol, nicotine or coffee, and sometimes even from diseases. Hair ageing is a natural physiological process that affects everyone. The pigment-producing cells - the melanocytes - start to function less and less over time. They produce less pigment and the hair follicles shrink, supplying less and less nutrients to the roots. This is what causes hair to turn grey, become thinner by the day and eventually fall out.