Is Flo safe? Period tracker privacy, explained

A plain-English guide

"Is Flo safe?" is one of the most-searched questions about period apps, and it's a fair one. Flo is the most-downloaded period and ovulation tracker in the world, and it works well. But "does it work" and "is my data safe" are two different questions.

What period trackers collect

A typical cloud-based tracker asks you to log some of the most sensitive information you have: cycle dates, sexual activity, symptoms, moods, pregnancy attempts and outcomes. Because these apps run on company servers, that information is uploaded, stored, and processed off your phone — which is what makes monetization, breaches, and legal requests possible in the first place.

What the FTC found about Flo

In January 2021, the U.S. Federal Trade Commission announced a settlement with Flo Health over allegations that the app had shared users' health information with third parties — including Facebook and Google — despite promising to keep that information private. As part of the settlement, Flo was required to obtain an independent privacy review and to notify affected users. Flo has since introduced privacy features such as an "Anonymous Mode."

The point isn't that Flo is uniquely bad — it's that even a major, well-resourced app got this wrong, which tells you something about the model itself. When data leaves your device, keeping it private becomes a promise rather than a guarantee.

So, is Flo safe to use today?

Flo has made privacy improvements, and many people use it comfortably. If you do, it's worth turning on its privacy features and reading its current policy. But if your goal is for your cycle data to be structurally private — not dependent on a company's policies, vendors, or future ownership — a cloud app can't offer that. Only an app that never sends your data anywhere can.

The more private approach: keep it on your device

An offline period tracker sidesteps the entire issue. Hoo-Ha contains no networking code at all, requires no account, and stores everything locally on your iPhone, encrypted with AES-GCM. There's no server to breach, no data to sell, and nothing to share by accident — and it's a one-time purchase with no subscription.

Want the short answer? Flo is usable and has improved, but it's a cloud app, so privacy depends on trust. If you want privacy by design instead, choose a tracker that works entirely offline.

Compare private period trackers

This article is general information, not legal advice. Company practices and policies change over time; check each app's current privacy policy. Flo, Facebook, and Google are trademarks of their respective owners.