Does hair color developer go bad?

« Reply #1 on: 22 May 11 / 02:31 PM » Yes they will eventually expire but if it's sealed and kept away from heat, sunlight, extreme cold etc then you should be fine if your talking months rather than years. read more

Yes, developer does go bad. According to Sally Beauty Supply, hair color products have freshness dates stamped on them. But manufacturer testing has shown that the shelf life of hair color product is almost unlimited if the bottle has never been opened. Other sources suggest that most developers have a shelf life of 12 months. read more

Developer is hydrogen peroxide H2O2. It’s really water H2O with an extra oxygen. Adding developer to haircolor makes it alkaline and triggers the decomposition of the peroxide. read more