Flo vs Stardust: Which Period Tracker Fits You? (2026)
Flo suits you if you want a large community, a deep content library and a long-established app. Stardust suits you if you want moon-phase and daily hormone content that feels fun to open. Both have documented privacy histories, laid out below with sources. Veya, our app, is a third option if you want cycle tracking next to other health data.
Full Transparency
This comparison is published by Holland Neurotech Inc., the company behind Veya. We've included Veya as a third option where relevant. We've done our best to compare Flo and Stardust fairly based on each app's published features, pricing, and public record. If Flo or Stardust is the better fit for you, use it.
Quick Answer
Here's the short version by what you want from a tracker, with prices as listed on the US App Store in October 2026:
- If you want a large community and a deep content library: Go with Flo. Over 570M downloads per its App Store listing, a Premium health assistant, and a large content library.
- If you want a tracker that feels fun to open every day: Go with Stardust. Moon-phase and hormone-stage content, cycle sharing with friends.
- If you want cycle, mood, sleep, and nutrition tracking in one free app: Try Veya.
If you're weighing a third option, see how switching to Veya works.
Flo and Stardust are two of the most-discussed period trackers right now, and the comparison isn't really "which one is better." It's closer to "which one is built for the reason you open a period tracker in the first place." Flo is the polished, feature-complete option, with over 570 million downloads according to its App Store listing (as of October 2026). Stardust is the smaller, design-forward option that leans into moon phases and daily hormone explanations, and it's become one of the apps Gen Z talks about most on TikTok.
Both apps also have documented privacy histories worth knowing before you hand over cycle data, and both have made real changes since the incidents that put them in the news. We'll walk through what you get with each, lay out the privacy record for both plainly, and cover a third option built around a different premise entirely.
The Short Version
If you're in a rush, here's the quick breakdown:
| Flo | Stardust | Veya | |
|---|---|---|---|
| Best for | Feature depth and community | Daily ritual, astrology/lifestyle feel | All-in-one health tracking |
| Platform | iOS + Android | iOS + Android | iOS only (+ web app) |
| Scale | 570M+ downloads | 4.8 stars, ~119K ratings | Smaller, newer app |
| Free tier | Usable; some features Premium | Usable core tracking | Most features, no ads |
| Premium price | $47.99–$59.99/year | $24.99–$39.99/year | ~$49.99/year |
| Privacy | FTC order, class action, 2025 Meta verdict | 2022 criticism; July 2026 Mozilla review | Strong, no ads |
Want more detail? Keep reading.
What do you get with Flo?
Flo is one of the most widely downloaded period trackers, with over 570 million downloads worldwide according to its App Store listing (as of October 2026). It may well be on your friends' phones already, and that scale shows up in the feature list.
Features
- Cycle tracking with AI-powered predictions
- A Premium virtual Health Assistant that checks in on symptoms like cramps, fatigue, and mood
- A health article library reviewed by medical experts, per Flo
- Secret Chats: anonymous community discussions (listed as a Premium feature on the App Store)
- Pregnancy mode with week-by-week updates (in-depth pregnancy features are Premium)
- Apple Health integration and an Apple Watch companion app
- Partner sharing for joint tracking
Strengths
The community is a big draw. Secret Chats put you in anonymous discussions with other users on topics from PCOS to perimenopause. If you have a question about a symptom at 2am, someone in that community has probably already asked it.
The content library is extensive. Articles cover cycle, fertility, and general health topics, and Flo says medical experts review them. If you want to learn while you track, few trackers put as much reading in the app.
Pregnancy mode. Flo includes pregnancy tracking with weekly updates and educational content, though in-depth pregnancy features sit behind Premium.
Limitations
Privacy is the big concern. The FTC finalized an order against Flo in June 2021 after alleging Flo shared sensitive health data from millions of users with firms including Facebook and Google despite promising privacy; the order did not include a fine. A separate class action over the same 2016–2019 data sharing reached a proposed $59.5M settlement with Google, Flo and Flurry (Flo's share: $8M; the defendants deny wrongdoing). It received preliminary approval in April 2026, with a final approval hearing set for October 29, 2026 (court-approved notice). Separately, a jury found Meta liable in August 2025 (Femtech Insider). Flo has since added Anonymous Mode, which its App Store listing describes as letting you track without personal identifiers linked to your health data.
Paywalls. Flo Premium unlocks features such as the virtual Health Assistant and expert-led videos (annual plans are listed at $47.99–$59.99 in the US App Store as of October 2026).
No nutrition, habit, or sleep tracking. Flo stays focused on cycle and pregnancy tracking. You won't find meal logging or habit tracking inside the app.
Pricing
Free: Core cycle and symptom tracking; some features sit behind Premium.
Flo Premium: annual plans are listed at $47.99 and $59.99 in the US App Store (as of October 2026). Adds the virtual Health Assistant, expert-led videos and more, per its App Store listing. Check current pricing in-app, as it can shift with promotions.
Download: Available on iOS and Android
What do you get with Stardust?
Stardust pairs standard period tracking with moon phases, hormone-stage explanations, and a distinct visual style that's made it one of the more-discussed period apps on TikTok. Its App Store listing shows a 4.8 out of 5 rating across about 119K ratings (as of October 2026).
Features
- Cycle tracking with a daily readout of where you are hormonally and what that can feel like
- Cycle syncing content that aligns your cycle with lunar phases, plus a moon calendar
- "Cycle Horoscope" and zodiac-matched content
- Sleep and activity insights layered onto cycle tracking, plus the option to connect wearables like Apple Watch and Oura Ring for basal body temperature
- Sharing with partners or close friends
- Pregnancy Mode with week-by-week tracking, and standard symptom, mood, and period logging
Strengths
It's genuinely fun to open. Stardust is one of the few trackers people describe that way. The daily hormone narrative and moon-phase framing make cycle education more approachable than a plain calendar view, and that's a real reason people stick with a tracker instead of abandoning it after a week.
It's free to download. The App Store lists Stardust as free with in-app purchases, so check which features sit behind the paid tier before you rely on them.
It responded to the 2022 criticism. After TechCrunch's reporting, Stardust revised its privacy policy to remove its end-to-end encryption mentions, and it says it has never received a request for user data from authorities or third parties (statement to TechCrunch, July 2026).
Limitations
The 2022 criticism is worth knowing. TechCrunch found that Stardust periodically sent users' phone numbers to the analytics firm Mixpanel, and the company's encryption claims did not hold up as marketed. The company updated its policy afterward.
More recent privacy scrutiny exists too. On July 16, 2026, Mozilla published a hands-on review of six period trackers. As reported by PPC Land, Stardust scored 2 out of 10, against 8 for Clue and 7 for Flo. TechCrunch reported that Stardust was the only one of the six to send sensitive health data (birthdate, contraceptive method, family-planning intentions and symptoms) to another company, the analytics firm RudderStack, tied to an identifier rather than a name. A Stardust spokesperson said RudderStack is "contractually prohibited from selling or using it for its own purposes." Mozilla also found the main privacy policy had been revised twice in roughly seven months, naming Meta's and Google's ad-measurement tools as partners as of May 2026 (per PPC Land). Stardust told TechCrunch it "has never received any requests, demands, or legal process for user data from authorities or third parties." Read Stardust's current privacy policy yourself before logging sensitive symptoms.
Check the privacy label. Stardust's App Store listing shows purchases, identifiers and usage data among the data used to track you. If that rules Stardust out for you, our Stardust alternatives roundup looks at six other trackers.
Pricing
Free: Download is free; the paid tier unlocks more (see below).
Paid plans: the US App Store lists a $6.99 Monthly Plan and annual plans at $24.99–$39.99 (as of October 2026, per the listing). Check current pricing in-app.
Download: Available on iOS and Android
Is there a third option besides Flo and Stardust?
All three apps track the cycle on its own, and none of them connects mood, sleep or food to the phase you're in.
Veya logs those alongside your cycle and shows how they move across phases. If you're leaving Flo, you can import your cycle history from a screenshot in the web app, so you don't start from a blank calendar. Your imported dates show up in your cycle history. Mood and sleep logging start the same day.
Checked October 24, 2026 against the current App Store listings and Veya's web app.
Veya is a newer app with a smaller community than Flo, and the full app is iPhone only, with a web app for everything else.
Side-by-Side Feature Comparison
Here's every major feature compared across all three apps. Check marks mean the feature is included, locks mean it requires a paid subscription, warning signs mean it's limited, and X marks mean it's not available.
| Feature | Flo | Stardust | Veya |
|---|---|---|---|
| Cycle tracking | ✅ | ✅ | ✅ |
| Pregnancy mode | ✅ (in-depth features Premium) | ✅ Pregnancy Mode | ✅ |
| Mood / symptom tracking | ✅ | ✅ Standard logging | ✅ Detailed |
| Moon-phase / astrology content | ❌ | ✅ Core feature | ❌ |
| AI assistant | 🔒 Paid | ❌ | 🔒 Paid |
| Community | ✅ Secret Chats | ⚠️ Friend syncing only | ❌ |
| Sleep / activity tracking | ❌ | ⚠️ Sleep/activity insights | ✅ Full logging |
| Nutrition tracking | ❌ | ❌ | ✅ |
| Content library | ✅ Large article library | ✅ Daily readouts | ⚠️ Limited |
| Privacy practices | ⚠️ FTC order, class action, 2025 Meta verdict | ⚠️ 2022 issues; 2026 Mozilla review | ✅ No ads, no data selling |
| Free tier quality | ⚠️ Usable; some features Premium | ✅ Usable core tracking | ✅ Generous, no ads |
| Price (annual) | $47.99–$59.99/yr | $24.99–$39.99/yr | ~$49.99/yr |
Should you choose Flo or Stardust?
There's no single "best" app here. It comes down to what actually gets you to open a tracker consistently. Here's the honest breakdown:
Choose Flo if:
- You want a large community and a deep content library
- Health education and expert-reviewed articles matter to you
- You want pregnancy tracking in the same app as cycle tracking
- You need Android support
- You're comfortable with Flo's privacy history (or willing to use Anonymous Mode)
Choose Stardust if:
- You stopped opening other trackers because they felt like a chore
- You like moon-phase and daily hormone content more than a plain symptom log
- You want to sync cycles with friends inside the app
- You want a free-to-download app with a distinct visual style
- You've read the current privacy policy and are comfortable with it
Choose Veya if:
- You want cycle, mood, sleep, fitness, and nutrition tracking in one app
- You want to see how your lifestyle habits connect to your cycle
- You want a generous free tier with no ads
- You're on iOS (or okay using the web app on other platforms)
- Community and daily content aren't why you open a tracker
If TTC and conception features matter more to you than Stardust's daily-ritual aesthetic, see how Flo compares to a TTC-focused app instead in our Flo vs Glow comparison.
What do Flo's and Stardust's privacy records show?
Period data is sensitive, and both apps have a documented history worth reading before you commit. Here's the factual record for each, with sources, as of October 2026.
Flo: FTC Order, Class Action, and a 2025 Verdict
The FTC finalized an order against Flo in June 2021 after alleging Flo shared sensitive health data from millions of users with firms including Facebook and Google despite promising privacy; the order did not include a fine. A separate class action over the same 2016–2019 data sharing reached a proposed $59.5M settlement with Google, Flo and Flurry (Flo's share: $8M; the defendants deny wrongdoing). It received preliminary approval in April 2026, with a final approval hearing set for October 29, 2026 (court-approved notice). Separately, a jury found Meta liable in August 2025 (Femtech Insider).
Flo has since added Anonymous Mode, which its App Store listing describes as letting you track without personal identifiers linked to your health data. These are real changes, made after years of public scrutiny. Whether that history changes your decision is a personal call.
Stardust: 2022 Criticism, Then a 2026 Mozilla Review
In June 2022, TechCrunch reported that Stardust periodically sent users' phone numbers to the analytics firm Mixpanel (TechCrunch saw no health data shared with it), and that Stardust's promised end-to-end encryption was unclear: the founder described standard SSL traffic and AES-256 storage on AWS. Its privacy policy at the time allowed disclosure to law enforcement "whether or not legally required," which drew attention after Roe v. Wade was overturned. After TechCrunch got in touch, Stardust revised the policy to remove its end-to-end encryption mentions.
Stardust says it has never received a request for user data from authorities or third parties (statement to TechCrunch, July 2026).
On July 16, 2026, Mozilla published a hands-on review of six period trackers. As reported by PPC Land, Stardust scored 2 out of 10, against 8 for Clue and 7 for Flo. TechCrunch reported that Stardust was the only one of the six to send sensitive health data (birthdate, contraceptive method, family-planning intentions and symptoms) to another company, the analytics firm RudderStack, tied to an identifier rather than a name. A Stardust spokesperson said RudderStack is "contractually prohibited from selling or using it for its own purposes." Mozilla also found the main privacy policy had been revised twice in roughly seven months, naming Meta's and Google's ad-measurement tools as partners as of May 2026 (per PPC Land). Stardust told TechCrunch it "has never received any requests, demands, or legal process for user data from authorities or third parties." Read the current version of the policy yourself if this is a deciding factor for you.
Veya: Privacy-Focused, Smaller Scale
Veya doesn't run ads and doesn't sell user data. That said, it's a newer, smaller company without the years of public scrutiny that Flo or Stardust have been through, and there's no GDPR certification since it's a US-based company. The no-ads, no-data-selling approach is a meaningful commitment, but it hasn't been tested by the same level of outside review.
Frequently Asked Questions
Is Flo or Stardust more accurate for period predictions?
Neither Flo nor Stardust publishes independent accuracy data that we could find, and both rely on your logged history to predict. For irregular cycles, expect predictions from any app to be less reliable, and focus on the patterns you log rather than trusting the forecast.
Which is better for privacy, Flo or Stardust?
Both have documented privacy issues worth knowing. The FTC finalized an order against Flo in June 2021 after alleging Flo shared sensitive health data from millions of users with firms including Facebook and Google despite promising privacy; the order did not include a fine. A separate class action over the same 2016–2019 data sharing reached a proposed $59.5M settlement with Google, Flo and Flurry (Flo's share: $8M; the defendants deny wrongdoing). It received preliminary approval in April 2026, with a final approval hearing set for October 29, 2026 (court-approved notice). Separately, a jury found Meta liable in August 2025 (Femtech Insider). In 2022, TechCrunch reported that Stardust periodically sent users' phone numbers to the analytics firm Mixpanel (TechCrunch saw no health data shared with it), and that Stardust's promised end-to-end encryption was unclear: the founder described standard SSL traffic and AES-256 storage on AWS. Its privacy policy at the time allowed disclosure to law enforcement "whether or not legally required," which drew attention after Roe v. Wade was overturned. After TechCrunch got in touch, Stardust revised the policy to remove its end-to-end encryption mentions. In July 2026, Mozilla's review scored Stardust 2 out of 10, Flo 7 and Clue 8 (PPC Land). Neither app is a clean slate, so check each one's current privacy policy yourself.
Does Stardust still share data with law enforcement?
Stardust told TechCrunch in July 2026 that it "has never received any requests, demands, or legal process for user data from authorities or third parties." In 2022, TechCrunch found its privacy policy allowed disclosure to law enforcement "whether or not legally required" (TechCrunch). Because Stardust is US-based, TechCrunch noted it can still receive law enforcement demands for data on its servers (TechCrunch, July 2026).
Is Stardust actually end-to-end encrypted?
In 2022 Stardust said it was working toward end-to-end encryption, but TechCrunch reported the founder described standard SSL traffic and AES-256 storage on AWS, which is not end-to-end encryption, and Stardust then removed the end-to-end encryption mentions from its policy. TechCrunch's 2026 coverage says its analysis found the end-to-end claim was false.
What's a good alternative to Flo and Stardust?
Veya, our app, is worth a look if you want cycle tracking alongside mood, sleep, fitness, and nutrition in one app, with correlation insights showing how your lifestyle connects to your cycle. Core features are free with no ads. The main tradeoffs are that it's iOS only (a web app covers other platforms) and has a much smaller community than Flo or Stardust.
Is Stardust just astrology, or does it track real symptoms?
Stardust's App Store listing describes period and PMS predictions, daily insights tied to cycle and hormone patterns, ovulation forecasts, Pregnancy Mode, and moon-related tools such as cycle syncing with lunar phases. If detailed symptom logging is your main goal, open each app and compare the symptom options before committing.
How much does Flo or Stardust premium cost?
As of October 2026, the US App Store lists Flo Premium annual plans at $47.99 and $59.99 (Flo listing) and Stardust annual plans at $24.99 to $39.99, with a $6.99 Monthly Plan (Stardust listing). Both apps are free to download, and pricing can shift or vary by promotion, so check the current price inside each app before subscribing.
Want to See More Apps Compared?
This guide focused on Flo vs Stardust, but there's more to look at depending on why you're comparing. If you're weighing whether to leave Flo entirely, or want the deeper science-vs-privacy angle, these go further.
- Flo Alternatives 2026: 7 Period Trackers Compared →
- How Accurate Are Period Tracker Apps, Really? →
- Flo vs Clue vs Stardust: 2026 Period App Showdown →
- Clue vs Stardust vs Glow: Period Trackers Compared (2026) →
Related Articles
- Period Tracking Guide: How to Track Your Cycle and Why It Matters
- Best Period Tracker App 2026: Clue vs Flo vs Ovia (6 Apps Compared)
Other App Comparisons
- Flo vs Natural Cycles: Which One Should You Use?
- Clue vs Natural Cycles: Which One Should You Use?
- Flo vs Ovia: Cycle & Pregnancy Compared (2026)
- Best Period Tracker App 2026: 6 Apps Compared
- Best Cycle Syncing Apps 2026: 28 vs Stardust vs MyFlo vs Flo
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