Meta’s Muse hits 10M US downloads in 40 days, a milestone reached by only 11 other apps

Sensor Tower data shows Meta's AI companion app Muse reached 10.9 million downloads since its September debut, 10.2 million of them in the US. Only 11 other apps have hit 10 million US downloads in their first 40 days, most of them games; the only other non-game apps were Threads and Disney+.

For comparison, ChatGPT had 3.7 million US downloads in its first 40 days, and Grok and Claude had 500,000 and 200,000. Muse also crossed 2.5 million daily active users for the first time on October 16 and has held the No. 1 spot on the US App Store on every day but one since launch.

Let's be clear about where the downloads came from. Meta can promote Muse across apps with 3.6 billion daily users, and Sensor Tower says Meta put 39% of its total ad spend behind Muse in October, up from 23% in September. Muse jumped from the 73rd to the 21st largest US brand by ad impressions. A launch with that much distribution and paid push is going to post big numbers. Comparing it with ChatGPT's first 40 days on mobile tells us at least as much about Meta's reach as about the product.

Retention is the better test, and here Muse looks genuinely strong. Sensor Tower puts its US 7-day retention at 30% and 14-day at 23%, against a rival average of 19% and 16%. People who try it are coming back more often than they do for the other assistants. That suggests the product is doing something users want, not just collecting curious installs.

What that something is matters. Muse is pitched as a companion that also handles tasks. Companion-style AI is where we see the most risk of dependency, especially for younger and lonelier users, and Meta's business is built on maximizing time spent. Strong retention in a companion app, backed by the biggest ad engine in the world, is a combination that deserves more scrutiny than a typical productivity tool.

We would also note the 2.5 million daily actives against more than 10 million downloads. That gap is normal, but it means most installers are not daily users yet. I'm watching whether the curve keeps climbing once Meta eases the ad spend.

Muse is currently available only in the US and Canada. Globally, ChatGPT still leads on early downloads, with about 15 million in its first 40 days, helped by markets such as Japan, which made up 25% of its early installs. Threads, the last app to hit the milestone, did it in July 2023 by leaning on Instagram's social graph.