comparisons
Published by Floriva · Updated 2026-04-01 · How Floriva checks its guides
Flo vs Natural Cycles: FDA Contraception or Free App (2026)
Flo: free, $59.5M settlement for sharing data with Facebook. Natural Cycles: $99.99/yr, FDA-cleared as birth control. Both store cycles on servers.
Natural Cycles is an FDA-cleared contraceptive app built around basal body temperature tracking, a fundamentally different product than Flo. Flo settled a $59.5M class action in 2025 for sharing reproductive health data without consent. Both apps require an account and server-side storage.
Two different products competing in the same category
Flo is a general-purpose period and symptom tracker. Natural Cycles is an FDA-cleared contraceptive device that happens to be an app. The comparison only makes sense once you understand that distinction.
If contraception is your primary goal, Natural Cycles is the only app in this category with FDA De Novo clearance for contraceptive use. That clearance means the FDA reviewed clinical evidence for effectiveness, something no other period tracker has done. The trade-off is cost ($12.99/mo) and daily commitment: you take your basal body temperature every morning before getting up.
If general cycle tracking and symptom logging is your goal, Flo's free tier covers the basics. But Flo's data practices are a documented problem. The FTC found in 2021 that Flo shared health data 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).
The privacy gap neither closes
Both Flo and Natural Cycles require an account. Both store your data on company servers. Neither offers on-device-only architecture.
This matters because server-side storage means data exists somewhere that can receive a subpoena. In states with abortion restrictions, period data has been sought as evidence. GDPR compliance (Natural Cycles is Sweden-based) limits commercial misuse but does not prevent law enforcement access.
Floriva takes a different position. Core records stay on your device, no account is required for core tracking, and optional encrypted sync is not readable by Floriva. The FDA clearance for contraception that Natural Cycles holds is genuinely valuable. Floriva does not offer that. But for cycle tracking with less company-side legal exposure, local-first architecture gives stronger structural protection.
Cost breakdown
Natural Cycles is the most expensive option in the space at $12.99/mo or $99.99/yr (as of original publication; check current rates at naturalcycles.com). Flo Premium is $4.99/mo or $39.99/yr. Floriva is a paid app with no free tier; plans are shown in the app. If you need FDA-cleared contraception, Natural Cycles' price is justified. If you need cycle tracking and privacy, Floriva has no readable central cycle database.
Cited signals
- Flo Health paid a $59.5M combined settlement for sharing reproductive health data without user consent Reuters / FTC, September 2025
Flo vs Natural Cycles vs Floriva: Features and Privacy
| Feature | Floriva | Flo | Natural Cycles |
|---|---|---|---|
| FDA-cleared contraception | No | No | Yes (De Novo 2018) |
| Temperature tracking | Yes | Optional | Required |
| On-device storage | Yes | No | No |
| Account required | No | Yes | Yes |
| FTC enforcement history | No | Yes (2021) | No |
| Data can be subpoenaed | No | Yes | Yes |
| Price | Paid app (no free tier) | Free / $4.99/mo | $12.99/mo |
Strengths and trade-offs
Floriva
Pros
- On-device storage, nothing on servers to subpoena
- No account required
- Paid subscription for all users, no free tier
- Privacy is architecture, not policy
Cons
- Not FDA-cleared for contraception
- Smaller feature set at launch compared to established apps
Flo
Pros
- Free tier functional for basic tracking
- Broad symptom and mood logging
- Large user base improves predictions
Cons
- FTC-confirmed data sharing with Facebook and Google (2021)
- $59.5M class action settlement (2025)
- Server-based data with subpoena exposure
- Not suitable for contraception decisions
Natural Cycles
Pros
- FDA De Novo cleared for contraception
- Algorithm built on peer-reviewed fertility research
- No documented data-selling history
Cons
- Requires daily temperature measurement, not passive
- Most expensive period tracker at $12.99/mo
- Server-based, data accessible via legal process
- Effectiveness depends on consistent user behavior
What the experts say
These apps promised users privacy while systematically routing reproductive health data to third-party advertising networks. Policy claims were never backed by architecture.
Quick answers to the obvious questions.
Is Natural Cycles FDA approved?
Natural Cycles received FDA De Novo clearance in 2018 as a contraceptive app, the first digital contraceptive to receive this designation in the US. De Novo clearance means the FDA reviewed the clinical evidence and found the device to be safe and effective for its intended use. This is different from general FDA approval but represents meaningful regulatory oversight of the contraceptive claims.
Does Natural Cycles sell user data?
Natural Cycles has not faced the same FTC enforcement actions as Flo. The company is Sweden-based and operates under GDPR, which restricts commercial data sharing. However, Natural Cycles does require an account and stores data server-side, so the data exists on their servers and is theoretically accessible to law enforcement via court order.
What is the cheapest private period tracker?
Floriva is a paid app with no free tier, with on-device-only storage and no account required. Euki and Drip (Android) are free and also use on-device storage. Natural Cycles is the most expensive at $12.99/mo and does not offer on-device architecture. Flo's free tier is functionally usable but carries a documented data-sharing history.
Questions people ask before they switch.
Can I use Natural Cycles as birth control?
Natural Cycles is FDA-cleared as a contraceptive method with a certificate De Novo, making it the first app cleared for this purpose in the US. Typical use effectiveness is 93%, which is lower than hormonal methods. It requires consistent daily basal body temperature tracking and works best for people with regular cycles.
What happened with Flo and the FTC?
The FTC found that Flo shared users' reproductive health data, including period dates, pregnancy status, and health symptoms, with Facebook, Google, and Flurry without user consent, despite promises of confidentiality. The FTC took enforcement action against Flo in 2021. A class action lawsuit over the same conduct settled for $59.5M in September 2025 (Reuters 2025-09-25).
How much does Natural Cycles cost vs Flo?
Natural Cycles is $12.99/mo or $99.99/yr with no free tier. Flo has a free tier and a premium subscription at $4.99/mo or $39.99/yr. Floriva is a paid app with no free tier but also no data selling, the cost reflects on-device architecture without ads.