Many advertisers' instinct is to target as narrowly as possible. But on TikTok, the delivery algorithm is smart enough that the opposite often performs better.
With a broad audience, the system has more room to find people who respond to your creative. Signals from each interaction sharpen delivery over time — while narrow audiences drive CPM up and saturate quickly.
Use broad targeting when: your product has mass appeal, the budget covers the learning phase (at least 50 conversions per ad group), and your creative is proven. Go narrow when the product is clearly niche or you need message control per segment.
A safe rollout: keep age and location limits that fit the product, enable audience expansion in your ad group on AdHub.la, and run one broad group against one narrow group for 7 days before committing budget.