Flo Health is the company behind Flo, a period, ovulation, and pregnancy tracking app. Flo claims over 420 million users worldwide. Mozilla Foundation counts 81 million monthly active users. This flo health review covers how the app works, what users say, what it costs, and how it handles private data.
Flo predicts periods and fertile windows from logged data. Users praise the clean design and accurate tracking. Complaints focus on subscription charges and cancellations. Privacy history includes an FTC settlement and an $8 million lawsuit settlement. Yet Mozilla testers found no health data sent to ad partners, and Anonymous Mode adds protection.
The free tier covers the basics, while Premium adds Secret Chats and a Symptom Checker. The real question is fit. Some users need only a calendar. Others want symptom tools. Read on to learn which group fits you, what Flo costs, and how to avoid billing surprises before you download.
What Is Flo Health?
Flo Health is the company behind Flo, a women’s health app that tracks periods, ovulation, pregnancy, and perimenopause. The audience is huge. Flo claims over 420 million users worldwide, and Mozilla Foundation reports 81 million monthly active users. Our team at Eat Proteins checked both figures. Flo calls itself the world’s number one women’s health app.
Flo started as a simple cycle calendar. Today it works more like a health diary. Users log mood, sleep, energy, exercise, and symptoms. What’s more, the app turns those logs into predictions about fertility and cycle timing.
Who Is the Flo App For?
The Flo app serves anyone who wants to understand a cycle, plan a pregnancy, or follow a pregnancy. It also covers perimenopause, a stage many people track. Flo offers a separate mode for each goal. Partners can join through a sharing feature. Flo built that feature so partners learn how to support the person tracking. Many users start with a simple goal.
Who gets the most value? People with irregular cycles, because pattern spotting needs data. Flo says predictions improve once users log at least three previous periods. Casual users still get a clean calendar from day one.
How Does the Flo App Work?
The Flo app learns from logged dates and symptoms, then predicts the next period, fertile window, and ovulation. More logged data means sharper predictions. Flo says the app can start with no history. Accurate predictions arrive faster after three logged periods. Each prediction updates as entries arrive. The home screen shows the current cycle day.
Here’s the thing: the app also runs chat-style check-ins. Log cramps, and the assistant asks follow-ups about intensity and pain relief. Flo says in-house healthcare professionals review the tailored replies. Mozilla testers noted the questions keep coming.
Getting Started:
- Download the app and pick a goal such as cycle tracking or pregnancy.
- Enter the dates of recent periods.
- Log symptoms, mood, and sleep each day.
- Review the predictions and insights on the home screen.
Does Flo Predict Periods Accurately?
Yes. Flo reports that 90 percent of its users say the app predicts period start dates accurately. That figure comes from Flo itself, so it’s a company claim. Trustpilot reviewers back it up. One reviewer called the predictions accurate after just three cycles. Individual results vary. Cycle length changes the outcome. The app learns each user’s pattern.
Does that settle the question? Not fully. No app beats biology. Stress, illness, and irregular cycles shift dates. Still, Dr Allison Rodgers, a reproductive endocrinologist on Flo’s medical board, praised its fertile-day predictions.
What Features Does Flo Health Include?
The Flo app bundles cycle tracking, ovulation prediction, pregnancy tracking, a health library, and a set of calculators. Flo also adds perimenopause support and partner sharing. In short, the free version already covers the basics. A Healthnews video review agrees that both tiers deliver accurate predictions. Most are free to use. Flo adds new tools often.
Flo works with 120+ doctors and health experts, according to the company. The health library covers cycles, getting pregnant, pregnancy, and being a mom. And there’s an LGBTQ+ section too. Calculators handle ovulation, hCG, due dates, and implantation.
Key Flo Features:
- Period and cycle tracking
- Ovulation and fertility predictions
- Week-by-week pregnancy tracking
- Perimenopause tracking
- Partner sharing
- Anonymous Mode
- Health library and calculators
What Does Flo Premium Add?
Flo Premium adds paid tools such as Secret Chats and a Symptom Checker on top of the free tracker. Flo labels both features as new. The free version already delivers period and ovulation predictions. Premium targets users who want deeper insights and extra health tools. Both tools sit inside the app. Pricing depends on region. Reviews on Premium are mixed.
One App Store reviewer said Premium was worth paying for because it helped them understand their body. Another Trustpilot reviewer enjoyed the free trial. Bottom line: test the trial before committing.
What Do Flo Health Reviews Say?
Flo Health reviews lean positive overall, with a 3.9 out of 5 rating from 4,222 Trustpilot reviews. Praise centers on tracking and design. Complaints center on billing. The split matters. Our experts at Eat Proteins weigh both sides, because app quality and subscription practices are separate questions. Ratings shift over time. Recent reviews matter most.
Flo also advertises over 7 million 5-star ratings. That number comes from the company, and app store ratings skew toward happy users. Trustpilot paints a harsher picture. Which source is right? Both are, for different kinds of users.
Review Snapshot:
| Source | Rating or Claim | Main Theme |
|---|---|---|
| Trustpilot | 3.9 of 5 (4,222 reviews) | Praise for tracking, complaints about billing |
| Flo website | Over 7 million 5-star ratings | Company claim with positive user stories |
| Mozilla Foundation | 7 out of 10 privacy score | Careful sharing, heavy data collection |
What Do Users Praise About Flo?
Users praise Flo for simple tracking, accurate predictions, and a clean interface. Trustpilot’s summary also mentions supportive daily insights and pregnancy guidance. One reviewer wrote that the app stays very accurate even without Premium. Another liked the easy layout. Several mention the supportive tone. Trustpilot reviewers repeat these points often.
App Store reviewers describe the app as emotional support. One called it a friend that understands what they are going through. And one user credited the logs for helping them conceive. Those are personal stories, not clinical proof.
What Do Users Complain About?
Users complain mostly about subscription charges, aggressive upgrade prompts, and difficulty cancelling plans. Trustpilot’s summary flags unexpected charges and automatic renewals. One reviewer said they bought an annual plan by accident and could not cancel. That’s a serious concern on a tight budget. Reviewers want clear renewal notices up front.
The bad news? Complaints cluster around billing, not the tracker itself. Check the renewal terms before paying. Set a calendar reminder for the renewal date. And use the subscription manager that Flo links from its website.
Is Flo Health Safe and Private?
Yes. Flo is safer than most period trackers on data sharing, though it collects a large amount of personal health data. Mozilla Foundation scored its privacy 7 out of 10. Testers saw no health data sent to ad partners. Flo carries a long history of privacy problems, however. Controls are easy to find. Mozilla praised the plain-language explanations.
Mozilla’s testing found AppsFlyer pinged on launch, with or without tracking allowed. Turning tracking off removed most other ad systems. Flo says it does not share health data or detailed in-app browsing. Do those claims hold? Testing says mostly.
Privacy Timeline:
| Year | Event | Outcome |
|---|---|---|
| 2019 | Wall Street Journal report on health apps and Facebook | Flo named among the apps |
| 2021 | FTC case over health data handling | Settled in 2021 |
| 2025 | Lawsuit over data flowing to ad and analytics firms | $8 million settlement |
| April 2026 | Privacy policy update | Names TikTok Ad Manager and Firebase |
Has Flo Faced Privacy Lawsuits?
Yes. Flo settled an FTC case in 2021 and agreed to an $8 million settlement in a 2025 case. A 2019 Wall Street Journal report started the scrutiny. It found health apps, including Flo, sent in-app activity to Facebook through analytics tools. And the FTC echoed those concerns. Both cases involved health data. Both cases involved sensitive health data.
A Flo spokesperson told Mozilla the company has made significant investments in privacy and security since 2019. Is that enough? Judge for yourself. The track record is real, and so are the improvements. To be clear: past problems matter.
What Is Flo Anonymous Mode?
Anonymous Mode lets users run Flo without linking data to their name, email address, or technical identifiers. Users find it under Settings by tapping the profile picture. Predictions and insights still work. Mozilla testers saw AppsFlyer go quiet and traffic route through a Cloudflare relay. Flo calls the mode award-winning. The setting takes seconds.
There’s a catch, though. Mozilla turned it on six minutes into a session. AppsFlyer already had the device identifier by then. So switch it on before logging anything. Flo also offers an optional PIN lock for the app.
How Much Does Flo Health Cost?
Flo offers a free tier and a paid Premium subscription, and prices vary by plan length, region, and promotion. The sources our team reviewed list no single fixed price. One Trustpilot reviewer paid 15 dollars for an annual renewal after a promotion. Always read the checkout screen. Trial offers differ by region. Regional pricing differs across app stores.
Watch the trial terms. Reviewers report accidental annual purchases and renewal surprises. A trial that auto-renews is still a purchase. So why risk it? A short checklist helps avoid trouble.
Before You Pay:
- Read the trial length and renewal date
- Confirm monthly versus annual billing
- Screenshot the purchase confirmation
- Find the subscription manager early
Is Flo Premium Worth the Price?
No. Flo Premium is optional for basic cycle tracking, because the free tier already predicts periods and ovulation. Premium suits users who want Secret Chats, the Symptom Checker, and deeper insights. Our experts at Eat Proteins suggest testing the free version first. Results vary by user. Value depends on use. Value depends on how often users log.
Reviewers split here. One App Store reviewer called Premium worth paying for. Others felt pushed to upgrade. What decides it? Your goals. Trying to conceive or tracking symptoms? Premium may pay off. Just logging dates? Stay free.
Why Should You Try Eat Proteins?
Eat Proteins helps readers judge health and wellness products with sourced reviews before they spend money. Our team at Eat Proteins reads the sources, checks the claims, and flags the catches. Flo Health shows why that matters. A great app can still carry billing and privacy risks. Every review follows the same checklist. We update articles as facts change.
Pay attention to this: you now know Flo’s strengths and weak spots. The same approach works for every supplement and wellness app. You get the facts first. Then you decide. Subscribe below to get new Eat Proteins reviews.
What You Get From Eat Proteins:
- Plain-language product reviews
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What Should You Check Before Using Any Health App?
Smart users verify three things before using any health app: data privacy, billing terms, and medical oversight. Each check takes minutes. Skipping them costs more. Flo passes some checks and struggles with others. Its privacy controls are strong, and its medical board is named. Reviews reveal patterns fast. Mozilla reviews help with privacy checks.
Its billing complaints are real, though. So start with the free version. Turn on Anonymous Mode on day one. Set a renewal reminder if you buy Premium. And remember: the right app fits your goals, not the loudest ad.