Congratulations on your upcoming wedding!
There's a very good summary of health concerns related to hair dye by the American Cancer Society
As you'll read, some studies found a small connection between hair dye and blood diseases, but other studies did not. If there's a risk, the risk factors include:
- Hair dyes manufactured before 1980, which used more dangerous chemicals.
- Permanent or semi-permanent dyes, as opposed to the safer temporary dyes.
- Prolonged exposure, such as what a hairdresser experiences.
- Darker colored dyes.
There's no proof and very little chance that your hair dye affected your health in any way. If you want your hair to be a certain shade in August, but also want to be cautious, you can wait until the time approaches and use a temporary dye.
This is more of an issue for people interested in long-term use of hair dye, such as women who'd hate to let their hair turn grey but are also worried about prolonged exposure to chemicals. Some people decide that managing their hair color is very important to them, especially since there's no conclusive studies showing that it will compromise their health. Others wouldn't feel comfortable with even the small risk, so they decide not to dye their hair. I wouldn't criticize either group for making an informed choice.
We can't avoid every possible risk while living a normal life, so they key is to be aware of the tiny risks here and there and make our own decisions about which are worth it. If we avoided every possible risk then we'd never play sports, travel, take care of a sick friend, eat out, or do so many other things we do.