Hair dyes generally contain p-phenylenediamine, which has certain sensitization. It belongs to the third type of carcinogen recognized by WHO, but -it is nonsense to talk about toxicity without dose subjects. Those qualified manufacturers produce the hair dye products with limited dosage and safe composition of the formula, and meet the production requirements of the “Hygienic Standards for Cosmetics”.
The American Association for the Prevention of Cancer (ACS) also pointed out that there is no reliable evidence that cancer and hair coloring are necessarily related. Frequent dyeing can not only damage your hair, but also cause allergies. It will not increase your chances of developing cancer.
However, before using a hair dye, you must have a skin allergy test. Otherwise, a large area of scalp allergy will occur, the consequences will be very serious. Therefore, before dyeing hair, be sure to apply a little hair dye to the back of the elbow or ear. Observe the application site two days later. If there is a rash, it means you are allergic to this product. Please replace the product or the store.
By the way, try your best to choose packed in high-quality Aluminum Compressible Tubes with end collapsed, which is one of marks about qualified hair coloring products.