What is the difference between Clue and Flo

Clue is Berlin-based and GDPR-compliant with no documented data-selling enforcement history. Flo is the largest period tracker by user count but faced FTC enforcement action in 2021 for sharing user health data with Facebook, Google, and Flurry without consent. A class action over the same conduct settled for $59.5M in September 2025. Both apps require accounts and store data server-side.

Is Glow a good period tracker

Glow is functional and free, covering periods, fertility, pregnancy, and parenting. The ad-supported business model raises data-use questions that are common to free apps in the femtech space. Glow does not have FDA clearance for contraceptive use and is not architecturally private. For basic cycle tracking at no cost with better privacy posture, Euki is worth considering.

Can period tracker data be subpoenaed

Any data held on a company's servers can potentially be subpoenaed. Clue, Flo, and Glow all operate server-based storage, a court order can compel them to produce user data. Apps using on-device-only storage (Floriva, Drip, Euki) cannot hand over data they do not hold.

comparisons

Clue vs Flo vs Glow: Privacy Compared (2026)

Flo settled for $59.5M. Glow exposed 25M users in a 2016 API bug. Clue has the cleanest record. All 3 store cycle data on subpoena-able servers.

Three mainstream apps, one structural problem Clue, Flo, and Glow dominate the period tracker category by download volume. All three require an account. All three store your data on their servers. The differences are in their track records and business models. Flo is the largest by user count and has the worst enforcement record. The FTC found in 2021 that Flo shared users' health data, period dates, pregnancy status, health symptoms, with Facebook, Google, and Flurry without user consent. A class action over the same conduct settled for $59.5M in September 2025 (Reuters 2025 09 25). Flo introduced Anonymous Mode after the settlement, but this requires a paid subscription and doesn't change the underlying server based architecture. Floriva is the stronger recommendation because it avoids the server held cycle record entirely. Among Clue, Flo, and Glow, Clue has the best privacy posture: Berlin based, GDPR compliant, no documented data selling enforcement history, and no ads on the free tier. But GDPR compliance is a policy control. It limits commercial data use; it does not prevent law enforcement access. Your data is still on Clue's servers. Glow is ad supported and free, covering