A number of studies have investigated personal use of hair dyes and cancer risks, however the evidence is limited and conflicting. If there is a risk, it is more likely to be from chemicals used in dyes before 1980, with some studies indicating an increased risk of non-Hodgkin lymphoma. People most heavily exposed to hair dyes are not those who dye their hair, but hairdressers, many of whom are exposed to hair dyes on a daily basis. In 2008, the International Agency for Research into Cancer (IARC) said that hairdressers had a slightly higher risk of bladder cancer than the general population. However, cancer can take many years to develop and it is not clear if the higher cancer risk seen in today’s hairdressers reflects exposure to old chemicals that are no longer used, or whether modern dye ingredients pose a risk. In the 1970s, scientists found that some hair dye ingredients could cause cancer in animals, and the use of these chemicals has since been discontinued. Either way, hairdressers can reduce their exposure to workplace chemicals by wearing gloves. IARC also considered personal use of hair dyes, determining that there was no consistent evidence of increased incidence of cancer among people who dye their hair. Many cancer patients ask about hair treatments, like dye, while undergoing treatment. Chemotherapy affects hair differently from person to person. However, it is best not to use dyes or perms for around six months after finishing chemotherapy as hair is more fragile than usual, is more likely to get damaged and the scalp is more sensitive at this time. If you have concerns, always check with your doctor.