If you were getting solid results with a broad audience and now performance dropped after narrowing to 18–35 with interests, it's likely due to over-targeting too soon. Meta’s algorithm performs best when it has room to learn and optimize.
Audience Restriction
Going from a 600 million audience to a much smaller slice cuts off a lot of Meta’s flexibility. Even if you think you’re targeting the “right” users, Meta might’ve already been finding them within your broad setup.
Learning Phase Restarted
Changing the audience resets the learning phase, and within the first 24 hours, the algorithm hasn’t gathered enough signals yet to optimize effectively.
Interest Targeting Can Backfire
Interests may sound relevant, but they can narrow your pool too much or not reflect actual buying intent.
What You Should Do:
- Re-enable the broad audience campaign or duplicate it and run it alongside the narrowed version.
- Test age filters alone (e.g., 18–35) without interest layering—that often works better than combining both.
- Give the new audience setup at least 2–3 days, but don’t expect better results unless it's paired with strong creative performance.
If broad was working, lean into it—Meta’s current algorithm tends to favor fewer restrictions and more data to optimize effectively.