TikTok and Instagram Reels both centre on short vertical video, so the choice is less about format and more about audience, discovery, and where your effort pays off. TikTok tends to excel at discovery: its feed readily shows your videos to people who do not yet follow you, which helps a new business reach fresh audiences quickly. Instagram Reels sits within a wider platform you may already use for photos, stories, and direct messages, so it can be stronger for nurturing an audience that already knows you and for businesses whose customers live mainly on Instagram. Consider where your customers already spend time; a younger audience may lean toward TikTok, while an established Instagram following makes Reels a natural fit. Think about your capacity too: doing one platform consistently beats doing two half-heartedly. The good news is that the same vertical video can often be adapted for both, so many businesses start where their audience is strongest and later repurpose their best clips to the other. If you are unsure, begin with TikTok for its discovery advantage when you need new reach, or Instagram if your existing customers are already there, then expand once your routine is solid. Let your own results, not platform hype, guide where you invest.