Some people may encounter that age, language, gender, and the interests in your GA4 Demographic details report have no data：
The age, language, gender, and the interests distribution of users in GA4 are obtained through Google Signal. If you do not enable Google Signal, it will display no data.
In GA4, click 「Admin」 – 「Data Settings」- 「Data Collection」，and then check 「Enable Google Signal Data Collection」, Demographic report in GA4 will have data:
There are many mechanisms to protect user privacy in GA4, and Data thresholds is one of them.
If the data is too small and does not exceed the Data thresholds, the data in the demographic report will not be displayed.
You can use the chart on the right side of the report name to judge whether the report applies Data thresholds：
If the report applies Data thresholds, it is recommended to select a longer time period or wait to collect more data.
Server Side Tagging
If your GA4 passes Server Side Tagging, then the Demographic report has no data by default.
Because Server Side Tagging does not support Google Signal.
If allow_google_signals is set to false, Google Signal is turned off by default, which will also result in no data in the Demographic report: