Will it be unlucky to lose your birthday?

No, according to the query of Gankun Nebula. The date of birth is just a traditional culture, which represents the eight elements of a person's birth, such as date, time and earthly branch. Therefore, it is not unlucky to lose the date of birth. Birthdays can help people know when a person was born. It is not a tool to predict the future, nor will it affect people's luck.