Comparison

Sunlighten vs Function Health

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Sunlighten

Optimize your well-being with this app, designed to enhance your light therapy and sauna experiences. Create personalized wellness programs, track sessions in real-time, and control your devices remotely for a seamless health journey.

Highlights
  • Science-based wellness programs
  • Personalized program creation
  • Real-time session tracking
  • Remote sauna control (Wi-Fi)
  • Audio and lighting management
  • Red light therapy panel programs
Features
Read full description

Take your wellness journey to the next level with the Sunlighten app, designed to enhance your Sunlighten sauna and Sunlighten RED Light Therapy Panel experience and optimize your well-being. Stay in control, feel your best, and enjoy the full potential of Sunlighten products. Key Features: • Science-based wellness programs designed to help you reach your health goals. • Create your own personalized programs. • Real-time session tracking. • Schedule your sauna sessions to build a routine. • Remote sauna control for compatible connected saunas • Manage your sauna's audio and lighting settings. • Get the most of our your RED Light Therapy Panel with over 20 scientifically optimized programs and guidance from the leaders in light therapy. Owners of mPulse saunas and RED Light Therapy Panels can enjoy full access to all app features, while owners of Amplify, Signature, and Solo Rise models can take advantage of convenient audio control. Stay connected for exciting updates as we continue to enhance your Sunlighten experience!

About

Function Health

Take control of your health with comprehensive lab testing, personalized protocols, and AI-powered insights. Understand your body's data, track changes over time, and make informed decisions for long-term wellness. Connect wearables and upload records for a complete health picture.

Highlights
  • 160+ lab tests annually
  • Personalized health protocols
  • Private AI Chat for results
  • Connect health wearables
  • Advanced MRI & CT scans
  • Upload health records
Features
Read full description

Function membership helps you take control of your health with 160+ lab tests each year, personalized Protocols, and Private AI Chat—all backed by advanced science and your real data. Built with top doctors, Function gives you the power to understand your body, track how it evolves, and make meaningful change. NOW AVAILABLE: HOME OR OFFICE BLOOD DRAWS Schedule a concierge blood draw at your home or office. A licensed specialist comes to you and completes your blood draw in under 20 minutes. Available in select locations. 160+ LAB TESTS Membership includes testing for your heart, hormones, thyroid, liver, kidneys, toxins, nutrients, inflammation, autoimmunity, immunity and more. ADVANCED MRI & CT SCANS Detect early signs of cancer and hundreds of other potential conditions with the option to purchase advanced imaging for your brain, pancreas, liver, spine, ovaries, prostate, heart and much more. PRIVATE AI CHAT Ask questions about your results, identify meaningful patterns, and figure out where to focus next, with Private AI Chat—built in partnership with top clinicians. CONNECT WEARABLES Connect Apple Health and other health devices and wearables to see how your activity, sleep, and daily habits affect your lab test results and long-term health. PROTOCOLS Translate your lab results, scans and health history into clear, evidence-based plans for nutrition, activity, and supplements—all customizable to your goals and preferences. UPLOAD HEALTH RECORDS Upload past lab test results, scans, and other medical records for a more complete view of your health, all in one secure place. PROGRESS YOU CAN SEE Twice-yearly and On-Demand testing helps you track your results over time, monitor for early signs of disease, and identify where to focus next. ADVANCED LAB TESTS Membership includes 160+ lab tests, plus the option to purchase advanced On-Demand tests for: - Detection of 50+ cancers - Alzheimer’s risk detection - MTHFR gene variants - Advanced MRI and CT scans starting at $365 - Food allergies and sensitivities - …and much more ACCESSIBILITY What could cost as much as $15,000 on your own is included with membership for just $365/year. Lab testing is available at over 2,000 lab locations across the US, with no insurance needed. SECURITY Function was built for privacy and security. Function is built to HIPAA standards. Your information is secure. How it works: 1. Join Function and schedule your first set of lab tests. 2. Get your results and personalized Protocols. Ask questions with your Private AI Chat. 3. See your progress with 60+ lab tests at your Mid-Year Test. 4. Purchase MRI or CT scans and other advanced On-Demand Tests any time. DISCLAIMER Function Health is a technology company and not a laboratory or medical provider. All laboratory and medical services are provided by independent third parties. Function Health does not offer medical advice, laboratory services, a diagnosis, medical treatment, or any form of a medical opinion; its services are not a substitute for medical care, medical advice, and/or a detailed discussion with a physician or other licensed provider. If you have any questions regarding any laboratory results or any other information that you access through Function Health, you should contact a physician or other licensed provider. All material, information, data, and content that Function Health provides is strictly for general information purposes. For additional important information: https:// www.functionhealth.com/terms-of-service.

Screenshots

Sunlighten4 screens
Function Health4 screens

Verdict

The call

The clearest difference is review sentiment: Function Health at 62% against Sunlighten's 19%. Function Health also leads on rating (4.9 vs 2.8) and update cadence (weekly vs every 4 months). Sunlighten's advantage is monetization model (free vs subscription) and device support (3 vs 1). On price, ads, in-app purchases and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Function Health holds the better App Store score, 4.9 against 2.8. That said, the two scores are not equally well evidenced: Function Health has 25K ratings behind it against 77, so its average is the more settled of the two. Written reviews point the same way: 19% of Sunlighten's written reviews are positive against 62% of Function Health's.

UpkeepUpdate frequency

Sunlighten ships an update every 4 months, Function Health weekly. Both last shipped on October 3, 2026.

Scorecard6 real differences · 4 level
Sunlighten versus Function Health: the parameters behind the verdict, then further details
ParameterSunlightenFunction Health
PriceFreeFree
Rating2.8 (77 ratings)4.9 (25K ratings) — better
Positive reviews19.0% of reviews62.0% of reviews — better
Number of ratings7725K — better
Update frequencyEvery 4 monthsWeekly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterSubscription
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS15.1 — better16.4
Further details — not scored
Size53 MB201 MB
Age rating17+17+
DeveloperSunlighten IncFunction Health

Customer experience

Sunlighten

All ratings77 ratings
Positive33.8%
Neutral16.9%
Negative49.4%
Written reviews126 reviews
Positive19.0%
Neutral7.9%
Negative73.0%

Function Health

All ratings24,731 ratings
Positive99.0%
Neutral0.4%
Negative0.6%
Written reviews342 reviews
Positive62.0%
Neutral5.6%
Negative32.5%

User reviews

Sunlighten

From 77 App Store ratings

What we love

  • 🚀 Convenient remote control
  • 👍 Customizable programs
  • 🚀 Easy to use app
  • 👍 Enhances sauna experience

Room to improve

  • 🐛 Unreliable app connectivity
  • 🔒 Privacy concerns with data collection
  • 🐛 Inconsistent scheduling and remote start
  • 🐛 Buggy and glitchy app
  • 👎 Limited remote functionality

Function Health

From 25K App Store ratings

What we love

  • 🚀 Seamless process for blood tests and results
  • 📊 Comprehensive health insights and tracking
  • 🧠 Helpful clinician notes and recommendations
  • 👍 User-friendly and visually appealing app
  • 💰 Affordable compared to other options

Room to improve

  • 🔍 Lack of communication and support responsiveness
  • 🐛 Some bugs and usability issues in the app

Bugs and requests

Sunlighten

Reported bugs

4 issues
  • App fails to connect to sauna
  • Scheduled programs not running as expected
  • Inconsistent lighting controls
  • Tablet frequently restarts or loses connection

Requested features

4 requests
  • Remote start and preheat capability
  • Improved app stability and reliability
  • Better integration between app and sauna
  • More customization options

Function Health

Reported bugs

2 issues
  • App sometimes redirects back to the home screen when trying to view results
  • Occasional typos and formatting issues in the app

Requested features

3 requests
  • More customization options in the app settings
  • Ability to print or export test results and recommendations
  • Specific supplement recommendations rather than broad suggestions

In-app purchases

None

Sunlighten

No in-app purchases

None

Function Health

No in-app purchases

Questions

Is Sunlighten free?
Sunlighten is free to download, with no in-app purchases.
Is Function Health free?
Function Health is free to download, with no in-app purchases.
Which has better reviews, Sunlighten or Function Health?
Function Health is rated higher. Sunlighten averages 2.8 out of 5 from 77 ratings, while Function Health averages 4.9 from 25K ratings.
Do Sunlighten or Function Health have ads?
Neither Sunlighten nor Function Health shows ads.
Which is updated more often, Sunlighten or Function Health?
Sunlighten ships an update every 4 months, and Function Health weekly. Most recently, Sunlighten was updated on October 3, 2026 and Function Health on October 3, 2026.

Other comparisons