If stored properly and never opened, hair-dyes do not expire. However, they do go bad if they have been opened, used and not stored properly.
The average shelf life of an opened hair dye is around 1-2 years.
What Causes Hair-Dyes To Go Bad?
If left opened, air and moisture can cause oxidation in the dye. Micro-organisms may spoil the dye by thriving in the ammonia rich environment.
What Does Expired Hair Dye Look Like?
Expired hair dye have the following characteristics:
- Water-like Liquid – A thin layer of water-like liquid forms on the top of the dye. This means the chemicals inside the dye have spoiled.
- Bad Odor – The dye lets out a bad odor which is caused the micro-organisms thriving in it.
- Change in Color – You may notice that the color of the dye faded.