Meta's Muse hits 10.9 million downloads in 40 days, joining a 12-app club

Meta's AI companion app Muse has reached 10.9 million downloads since its September debut, and 10.2 million of those installs came from the United States, according to market intelligence firm Sensor Tower. That performance makes Muse only the twelfth mobile app in history to cross 10 million U.S. downloads within its first 40 days on the market. The last app to do it was Meta's own Threads, back in July 2023.

Sensor Tower Senior Insights Analyst Kara Lee said the other apps that reached this scale were largely mobile games. The milestone matters beyond bragging rights: it signals that consumer demand for agentic AI (apps that perform tasks on the user's behalf rather than just answer questions) can translate into mainstream mobile distribution, and it shows Meta can still mint breakout apps on demand. Takeaway: Muse is the fastest-scaling non-game app launch the U.S. market has seen since Threads.

How much of this is paid momentum?

The download numbers do not reflect organic demand alone. Meta is spending heavily: per Sensor Tower's data, the company allocated 39% of its total advertising spend to Muse in October, up from 23% in September. Muse also now ranks as the 21st largest brand in the U.S. by advertising impressions this month, up from 73rd in September.

That spend rides on top of Meta's built-in distribution. Muse is marketed across Meta's family of apps, which today counts 3.6 billion daily active users — the same playbook Meta used for Threads, which was built on Instagram's social graph and whose content was later integrated into Facebook and Instagram. The caveat writes itself: an install purchased with a 39 percent ad budget is a lead, not a verdict. Takeaway: the launch is as much a media-buy story as a product story.

Does Muse actually keep users?

By one measure, yes. Muse is outperforming its AI rivals on retention, the metric that usually separates marketing wins from durable products.

In the U.S., Sensor Tower measured:

• 30% retention at 7 days
• 23% retention at 14 days

By comparison, ChatGPT, Claude and Grok averaged a 19% 7-day retention rate and a 16% 14-day retention rate, according to the firm's data. Engagement is also climbing rather than decaying: Muse's daily active users reached 2.5 million for the first time on October 16, a 15% week-over-week increase. Takeaway: users who install Muse are, so far, coming back at rates its competitors did not match at launch.

How does Muse compare with ChatGPT's launch?

On U.S. ground, Muse dominates its first-40-day cohort:

• Muse: 10.2 million U.S. downloads
• ChatGPT: 3.7 million U.S. downloads
• Grok: 500,000 U.S. downloads
• Claude: 200,000 U.S. downloads

Muse shot to No. 1 on the App Store after debut and, at one point, outpaced some of ChatGPT's own post-launch metrics. It has held the No. 1 U.S. App Store rank every day except October 19, when the streaming app Kick briefly overtook it; Muse reclaimed the top spot as of Tuesday. It has also ranked No. 1 on Google Play over the past 30 days.

The global picture flips. ChatGPT scaled to roughly 15 million global downloads in its first 40 days, beating Muse's total. The comparison is not apples-to-apples: Muse is currently available only in the U.S. and Canada, while ChatGPT's app drew users from markets including Japan, Brazil and Germany. Japan alone accounted for 25% of ChatGPT's global installs during its first 40 days. Takeaway: Muse wins the U.S. launch race outright, but its global test has not started.

What happens when the ad budget normalizes?

The open question is durability. Sensor Tower's numbers cover 40 days, a window in which Meta was spending 39% of its advertising budget and pushing Muse to a family of apps with 3.6 billion daily users. Retention of 30% at 7 days is strong for the category, yet it also means seven in ten U.S. installers were gone within a week.

No data in the release speaks to what those users actually do inside Muse, how often the agent completes tasks successfully, or what any of this costs Meta in compute. Until Muse expands beyond the U.S. and Canada and holds its rankings without a record share of ad spend, the honest read is a paid-for launch with genuinely above-average stickiness — a strong start, not yet a settled outcome.