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Is Carbon Safe?

Carbon privacy label · by Reform, LLC · checked November 2026

  • Recently updated
App Privacy label Developer-reported · checked November 1, 2026
Used to track you
0types

None declared

Linked to you
6types
Not linked to you
2types
Short answer

Mostly a question of trust: Carbon collects data linked to you but declares no tracking. The sensitive items are sensitive info and user content. In total the label lists 7 data types; 59% of health trackers we checked declare tracking.

At a glance

Carbon privacy in one look

Data exposure on the label
Linked to you
  1. 1
  2. 2
  3. 3
  4. 4

Built only from the developer's App Store label. It describes disclosure, not tested behaviour.

Verdict from the label
Linked to you, no tracking

Carbon collects 6 data types tied to your identity but declares no tracking.

Try it

Did Carbon ask for something?

Pick the permission prompt you saw. We compare it with what Carbon's developer declared.

It asked me for access to…
Tap a prompt to compare it with the label.
Not on the label

Location is not on Carbon's label. That can be fine: data used only on your iPhone does not have to be declared. If the data would need to leave the phone for the feature to work, ask why it is missing.

Matches the label

Carbon lists User Content on its label, linked to you. Choose Limited Access and pick only the photos you want to share.

Not on the label

Contacts is not on Carbon's label. That can be fine: data used only on your iPhone does not have to be declared. If the data would need to leave the phone for the feature to work, ask why it is missing.

Not declared on the label

Carbon declares no tracking, so a tracking prompt would contradict its label. Decline it, and consider reporting the mismatch to Apple.

Not on the label

Health & Fitness is not on Carbon's label. That can be fine: data used only on your iPhone does not have to be declared. If the data would need to leave the phone for the feature to work, ask why it is missing.

A permission is what the app can reach on your iPhone; the label is what the developer says leaves it. They answer different questions.

Line by line

What Carbon collects, explained

Data typeWhat it coversWhere to limit it
Sensitive InfoSensitiveLinked to you Racial or ethnic data, sexual orientation, pregnancy, disability, beliefs, union membership, genetic or biometric data. Share only what the app needs and check whether the label lists this data as linked to you.
User ContentSensitiveLinked to you Messages, photos, videos, audio recordings, documents and support chats you create or upload. Settings › Privacy & Security › Photos: choose Limited Access or None; review Microphone and Files access too.
Contact InfoLinked to you Your name, email address, phone number or postal address. Use Sign in with Apple with Hide My Email where offered, and check the app's account and marketing preferences.
PurchasesLinked to you What you have bought or tend to buy. Review in-app marketing settings; subscriptions are listed in Settings › [your name] › Subscriptions.
IdentifiersLinked to you An account ID, screen name, customer number or a device-level ID such as the advertising identifier. Settings › Privacy & Security › Tracking: turn off Allow Apps to Request to Track, or tap Ask App Not to Track when prompted.
Usage DataNot linked to you What you tap, open and view inside the app, plus which ads you have seen. There is no single iOS switch. Look for an analytics or personalised-ads toggle in the app's own settings.
DiagnosticsLinked to youNot linked to you Crash logs, launch times, hang rates and energy use. Settings › Privacy & Security › Analytics & Improvements › Share With App Developers controls what Apple passes on; the app's own crash reporting is separate.
Reading the label

What Carbon's label means for you

Carbon's label has 6 types under “Data Linked to You”, 2 types under “Data Not Linked to You”. A data type can appear in more than one section when it is used for different purposes — for example, identifiers used for both analytics and advertising.

Carbon declares no tracking, which means the developer says it does not combine your data with other companies' data for advertising or sell it to data brokers. The data linked to you — sensitive info, user content, contact info, purchases, identifiers and diagnostics — is still tied to your identity, typically through an account, and is covered by the developer's privacy policy and retention rules.

The items that deserve the most attention are sensitive info and user content. These are the categories data-protection laws treat as special. Few apps need them.

Health trackers collect symptoms, vitals and habits. In the US, most consumer health apps are not covered by HIPAA, so the privacy policy is your main protection. Grant HealthKit categories one by one in the Health app, and avoid connecting categories the app does not need.

Among the 180 health trackers in our snapshot with a label, 59% declare tracking, 84% collect data linked to you and 3% say they collect nothing. Carbon lists 7 data types, more than the average of 5.1 for this group.

Health and fitness apps can read Apple Health data only for categories you approve, one by one. What they collect themselves is shown on the label.

On your iPhone

Settings to check for Carbon

  1. 1

    Tracking

    Settings › Privacy & Security › Tracking. If “Allow Apps to Request to Track” is off, apps cannot ask, and they are told to treat you as having declined. You can also turn it off for this app alone.

  2. 2

    Photos

    Settings › Privacy & Security › Photos. Limited Access lets you pick exactly which pictures the app can see; Add Photos Only lets it save without reading your library.

  3. 3

    Health

    Health app › your profile picture › Apps › Carbon. Turn categories on one at a time; the app cannot tell which ones you declined.

  4. 4

    Sign-in

    When creating an account, Sign in with Apple can give the app a relay address from Hide My Email instead of your real one.

  5. 5

    Lock the app

    On iOS 18 and later, touch and hold the icon and choose Require Face ID. Anyone who picks up your unlocked phone then needs your face, fingerprint or passcode to open it.

  6. 6

    Notifications

    Settings › Notifications › Carbon › Show Previews: When Unlocked keeps message and account details off the Lock Screen.

Cross-app tracking

Does Carbon track you?

No tracking declared

There is no “Data Used to Track You” section on Carbon's label.

Does Carbon track you? Full answer and how to stop it →

iOS 18 and later

Lock Carbon behind Face ID

  1. Find Carbon on your Home Screen or in App Library.
  2. Touch and hold the icon until the quick-actions menu opens.
  3. Tap Require Face ID (or Require Touch ID / Require Passcode, depending on your iPhone).
  4. Tap Require Face ID again to confirm. Carbon now asks for authentication every time it opens.

The lock is an iPhone feature, so it works whether or not Carbon has a passcode of its own. It does not change what the app sends to its developer.

Lock or hide Carbon: step-by-step guide →

From the App Store record

About Carbon

DeveloperReform, LLC
App Store categoryHealth & Fitness (also Lifestyle)
Latest version2.77.6010, released August 2026
First releasedApril 2020
RequiresiOS 16.6 or later
Size106 MB
Age rating17+
Languages1 (EN)
Bundle IDcom.joincarbon.nutrition

The current version shipped in August 2026. That is recent enough that the label should reflect current practices, but check the App Store page again before relying on it.

Read with care

What the label cannot tell you

  • A label is self-reported. Apple publishes the developer's answers and can reject apps that misrepresent them, but it does not independently verify what Carbon sends.
  • It does not say where data is stored, how long it is kept, whether it is encrypted, or which companies receive it. The privacy policy covers those points.
  • Optional data counts: if a feature lets you add something (a profile photo, a phone number), the type is listed even if you never use the feature.
  • Data handled only on your iPhone is not 'collected', so a no-collection label is compatible with an app that reads your files locally.
  • Third-party sign-in, payment processors and SDKs are supposed to be included, but a label can lag behind a new version.

The question to ask Carbon's developer: Is my health data shared with partners or used for ads?

How it compares

Carbon vs similar health trackers

Data types listed on each App Store privacy label
Tracks youLinked to youNot linkedCollects nothing

Fewer types is not automatically safer: a cloud backup app has to collect your files to work. Compare like with like.

Checking another app?

Look up any of our apps in seconds, or put two labels side by side.

App privacy checkerCompare two appsBrowse 4,500 apps
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AtoZ Health Tracker
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All health trackers → Who tracks you? A–Z → Apps that collect sensitive info → Privacy label decoder →

Do it now

Your Carbon privacy checklist

Tick what you have done
Tick each step as you do it on your iPhone.

Done. You have applied every control the label points to.

Quick quiz

True or false?

  1. Q1Carbon's privacy label says it uses data to track you.
    Right.
    Not quite.

    False: there is no Data Used to Track You section on Carbon's label.

  2. Q2Apple tests every app to confirm its privacy label is accurate.
    Right.
    Not quite.

    Labels are self-reported by developers. Apple can reject or remove apps that misrepresent practices, but it does not audit each label.

  3. Q3Carbon collects Sensitive Info.
    Right.
    Not quite.

    True: Sensitive Info appears on its label.

  4. Q4Data “Not Linked to You” is never sent off your iPhone.
    Right.
    Not quite.

    It is collected and sent; the developer says it is de-identified rather than tied to your account or device.

  5. Q5Tapping “Ask App Not to Track” can stop an app from working.
    Right.
    Not quite.

    Apple's rules require apps to work the same whether or not you allow tracking.

Questions people ask

Carbon privacy FAQ

Is Carbon safe to use?
Based on its App Store privacy label, carbon collects 6 data types tied to your identity but declares no tracking. Whether that is acceptable depends on what you will store in it. The label is developer-reported, not an independent security test.
Does Carbon track you?
No. Carbon's label has no Data Used to Track You section.
What data does Carbon collect?
Sensitive info, user content, contact info, purchases, identifiers, usage data and diagnostics. Of these, sensitive info, user content, contact info, purchases, identifiers and diagnostics are linked to your identity.
Who makes Carbon?
Reform, LLC, according to the App Store. It was first released in April 2020 and the current version is 2.77.6010.
Can I lock Carbon with Face ID?
On iOS 18 or later, touch and hold Carbon's icon and choose Require Face ID (or Touch ID / Passcode). This is an iPhone feature and works for most downloaded apps, whether or not the app has its own lock.
How does Carbon compare with other health trackers?
Across 180 health trackers with labels in our snapshot, 59% declare tracking and 3% say they collect no data. Carbon lists 7 data types against an average of 5.1.
Is my health data shared with partners or used for ads?
The privacy label cannot answer that. Look for it in Carbon's privacy policy or support pages, linked from the App Store listing. Grant HealthKit categories one by one in the Health app, and avoid connecting categories the app does not need.
How do I delete my data from Carbon?
Apps that let you create an account must also let you start account deletion from inside the app (an App Store rule since June 2022). Deleting the app from your iPhone alone does not delete data already sent to the developer.
Facts on this page come from Carbon on the App Store, as reported by the developer. Checked 2026-11-01. How we collect data · Report a correction