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Healthcare · head to head

Flo vs Signant Health

Flo logo

Flo

Healthcare

Period and cycle tracking app that settled with the US FTC in 2021 over sharing health data with third parties despite promising not to

From
Free
Rated
-
Full reviewWebsite
Signant Health logo

Signant Health

Healthcare

eCOA-first clinical trial platform that has grown outward into EDC, eConsent and televisits

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Flo has a free tier, so it costs nothing to try first.
  • Each has a real cost: Flo flo Health settled with the US FTC in 2021 over allegations it shared sensitive health data, including pregnancy and menstruation details, with Facebook, Google and other third parties despite telling users the data would stay private, a fact directly relevant to how much a user should trust current privacy claims without independently checking the published policy.; Signant Health no pricing is published, and the software licence is a minority of the real bill once instrument licensing, translations, device provisioning and services are added, so early budget estimates are routinely too low.
  • They diverge on capability: Flo covers Cycle and ovulation tracking, Signant Health covers eCOA and ePRO.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Flo and Signant Health actually diverge.

Attributes where Flo and Signant Health differ
AttributeFloSignant Health
Starting priceFreeOn request
Pricing modelFree with a Premium subscriptionquote
Free tierYesNo
PlatformsiOS, Android, WebWeb, iOS, Android

Identical on both: user rating (Not yet rated), category (Healthcare).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Flo

  • Cycle and ovulation tracking
  • Pregnancy mode
  • Anonymous Mode
  • Symptom and mood logging
  • Expert content library
  • Community and forums

Only in Signant Health

  • eCOA and ePRO
  • Unified platform
  • eConsent
  • Randomisation and supplies
  • TeleVisits
  • Rater training
  • Data surveillance
  • Instrument library

What people use each for

The jobs each tool is most often brought in to do.

Flo

  • Someone tracking cycle and ovulation who wants to weigh app convenience against the sensitivity of the data being loggednot Signant Health
  • A user in a jurisdiction with legal risk around reproductive health data who wants to check Anonymous Mode and current data sharing policy before logging pregnancy or fertility attemptsnot Signant Health
  • A buyer wanting to compare Flo directly against Clue on published data practices before choosing which app to trust with this informationnot Signant Health
  • Someone who wants pregnancy tracking content alongside cycle tracking in one app rather than switching apps mid-pregnancynot Signant Health

Signant Health

  • A central nervous system or psychiatry trial where the primary endpoint is a rated scale and rater consistency decides the readoutnot Flo
  • A global study needing an outcome instrument translated and linguistically validated across a dozen languagesnot Flo
  • A decentralised or hybrid protocol combining televisits, eConsent and at-home patient reported outcomesnot Flo
  • A sponsor consolidating separate eCOA, eConsent and randomisation vendors onto one platform to cut reconciliation worknot Flo

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Flo

  • Flo Health settled with the US FTC in 2021 over allegations it shared sensitive health data, including pregnancy and menstruation details, with Facebook, Google and other third parties despite telling users the data would stay private, a fact directly relevant to how much a user should trust current privacy claims without independently checking the published policy.
  • Reproductive health data, including logged periods, fertility attempts and pregnancy status, has been the subject of law enforcement data requests in some jurisdictions following changes to reproductive rights law, and cloud-stored logs are a real category of exposure regardless of a vendors intentions.
  • Anonymous Mode, the privacy feature introduced after the settlement, is a setting that must be checked and understood rather than assumed, and its exact scope and default status should be verified in the current privacy policy rather than taken from marketing copy.
  • Free tier predictions rely on self-reported symptom data and general population models, so accuracy for irregular cycles or specific medical conditions is limited compared with clinical tracking.
  • The subscription auto-renews and, like most mobile subscriptions, must be cancelled through app store account settings rather than inside the app itself.

Signant Health

  • No pricing is published, and the software licence is a minority of the real bill once instrument licensing, translations, device provisioning and services are added, so early budget estimates are routinely too low.
  • Linguistic validation is charged per instrument per language and is on the critical path to first patient in, so adding a country late in start-up produces both a cost and a schedule hit.
  • Provisioned participant devices bring logistics, replacement, shipping and cellular connectivity obligations that persist for the life of the trial and are frequently underestimated.
  • The EDC component is newer than the eCOA heritage, so sponsors with complex data management requirements often keep an incumbent EDC and lose the single-database benefit that justifies the platform.
  • It is priced and scoped for sponsor-grade trials, which makes it a poor fit for investigator-initiated or academic studies that need outcome collection without the services layer.

Pricing, plan by plan

Flo

Free
  • Flo Premium$11.99/month
    • Free tier covers core cycle tracking, predictions and symptom logging
    • Premium adds deeper personalised insights and expert content, around $11.99 a month
    • Annual and lifetime purchase options typically offered at a lower effective rate

Signant Health

On request
  • SmartSignals Unified Platform$undefined/year
    • Priced per study through a sales process
    • Modules selected per protocol: EDC, eCOA, randomisation, eConsent, TeleVisits
    • Instrument licensing paid to scale owners on top of platform cost

Which should you pick?

Choose Flo if

  • You need cycle and ovulation tracking.
  • You want to start without paying.
  • You work on iOS, Android, Web.
  • You also want pregnancy mode.
Flo review

Choose Signant Health if

  • You need ecoa and epro.
  • You work on Web, iOS, Android.
  • You also want unified platform.
Signant Health review

Questions people ask

Is Flo or Signant Health better?
Neither clearly leads. Flo starts at Free and Signant Health at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Flo or Signant Health?
Flo has a free tier; the other does not. Paid plans start at Free for Flo and On request for Signant Health.
Does Flo or Signant Health run on more platforms?
Flo runs on iOS, Android, Web. Signant Health runs on Web, iOS, Android.
Can I use Flo for free?
Yes. Flo has a free tier, so you can try it without paying. Signant Health starts at On request.
What is Flo best used for?
Flo is most often used for someone tracking cycle and ovulation who wants to weigh app convenience against the sensitivity of the data being logged, a user in a jurisdiction with legal risk around reproductive health data who wants to check anonymous mode and current data sharing policy before logging pregnancy or fertility attempts, a buyer wanting to compare flo directly against clue on published data practices before choosing which app to trust with this information, someone who wants pregnancy tracking content alongside cycle tracking in one app rather than switching apps mid-pregnancy. Of those, someone tracking cycle and ovulation who wants to weigh app convenience against the sensitivity of the data being logged and a user in a jurisdiction with legal risk around reproductive health data who wants to check anonymous mode and current data sharing policy before logging pregnancy or fertility attempts are not what Signant Health is typically brought in for.
What can Flo do that Signant Health cannot?
Flo covers Cycle and ovulation tracking, Pregnancy mode, Anonymous Mode, Symptom and mood logging. Signant Health covers eCOA and ePRO, Unified platform, eConsent, Randomisation and supplies.

Answered from the vendors’ own pages

Flo: What happened with the FTC in 2021?

The US FTC alleged Flo Health shared sensitive health data, including pregnancy and menstruation details, with third parties like Facebook and Google despite promising to keep it private. Flo settled without admitting liability, agreeing to obtain consent for future sharing and to an independent privacy review.

Signant Health: What is Signant best at?

Electronic clinical outcome assessment, particularly rated scales in central nervous system and psychiatry trials, together with rater training and endpoint quality services.

Flo: What is Anonymous Mode?

A privacy setting Flo states disconnects entered health data from an identifiable profile. Check the current app and privacy policy for whether it is on by default or must be turned on manually, since this affects what data is linked to your identity.

Signant Health: Is pricing published?

No. Everything is quoted per study, and instrument licences, translations and devices sit on top of the platform cost.

Flo: Is Flo free?

Core cycle tracking and predictions are free. Deeper personalised insights and expert content require Flo Premium.

Signant Health: Can I use it only for eCOA?

Yes. The modules are selected per protocol, and many sponsors take eCOA and eConsent while keeping an existing EDC.

Signant Health: What drives the timeline?

Translation and linguistic validation of outcome instruments, which is per language per instrument and sits on the critical path to study start.

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