Peptide Library

App comparison • 2026

Peptide Library vs Pep AI: GLP-1 Wellness Tracking or Peptide Research?

Nutrition, symptoms and AI on one side; research, vendor pricing and inventory on the other. Here is how they line up.

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Last verified · Published by Peptide Library, which has a commercial interest in this comparison. How we compare

Peptide Library app icon

Peptide Library

By Superfime LLC

A peptide research platform: cited research profiles, vendor and price comparison, tracking and inventory on iPhone, Android and the web.

Pep AI app icon

Pep AI

By Zode Development (pepaiapp.com)

A GLP-1 and peptide tracker built around shots, nutrition, side effects and wellness, with an AI companion, Apple Watch app and community groups.

Quick verdict

Peptide Library or Pep AI?

Pep AI is built around a GLP-1 routine: shots, food and protein, side effects, sleep and mood, with an AI companion called Arlo, an Apple Watch app and PDF reports. If that's your day-to-day, it's likely the better fit. Peptide Library is built for peptide research, with cited profiles, publication data and vendor price comparison, plus tracking and inventory, and its free plan includes tracking.

Peptide Library app icon

Peptide Library

Choose Peptide Library if…

  • You want to track without a subscription: Pep AI's listing says tracking needs a paid plan.
  • You research several peptides and want cited profiles and research statistics.
  • You buy research compounds and want vendor listings with price per mg.
  • You want a web app, or inventory with run-out and reorder-by dates.
Pep AI app icon

Pep AI

Choose Pep AI if…

  • You're on a GLP-1 medication and care most about food, protein, water and side effects.
  • You want photo meal scans and nutrition trends.
  • You want an Apple Watch app and an AI companion.
  • You want PDF reports to review with a healthcare provider.

At a glance

Feature comparison: Peptide Library vs Pep AI

Every cell comes from a cited source; numbers link to the source list at the end of the page. "Not advertised" means no source we checked mentions the feature, not that the app lacks it.

  • Verified
  • Verified, with limits
  • Verified absent or removed
  • Not advertised by the developer
  • Not verified (sources disagree or unclear)
Research4 features
Research: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Compound library
200+ profiles7
Not advertised

The current US description does not describe a compound library.

Cited research references
Yes7

PubMed, ClinicalTrials.gov, DailyMed and EMA references on profiles.

Not advertised
Publication and trial data
Yes8

Research Intelligence Center: publication and trial statistics.

Not advertised
Community research trends
Yes (full view with Pro)91
Not advertised
Vendor discovery4 features
Vendor discovery: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Vendor directory
Yes10
Not advertised
Vendor price comparison
Yes11
Not advertised
Price per mg
Yes111
Not advertised
Vendor reviews
Yes10
Not advertised
Availability4 features
Availability: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
iPhone app
Yes3
Yes14
Android app
Yes4
Yes15
Web app
Yes, installable5

Library, calculators and vendor prices need no account; tracking needs a free account.

Not advertised
Free plan
Yes (inventory: 1 peptide)1
Tracking needs a subscription14
Inventory4 features
Inventory: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Vial inventory
Yes (free: 1 peptide)1
Yes14

Vial inventory with photos.

Low-stock or run-out alerts
Yes4

Run-out and reorder dates with stock alerts.

Not advertised
Expiry dates
Yes4
Not advertised
Stock deducted on logging
Yes4
Not advertised
Tracking2 features
Tracking: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Dose logging
Yes14
Yes14
History and calendar
Yes4
Yes14

Dose history and a daily timeline.

Scheduling3 features
Scheduling: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Recurring schedules
Yes1
Yes14
Reminders
Yes16

App notifications; web push reminders on the website.

Yes14
Cycles and titration
Yes4

On/off cycles, every-N-days, several times a day and titration.

Not advertised

Weekly routines are described; cycles and titration are not.

Calculations2 features
Calculations: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Reconstitution calculator
Android and web124
Removed in 4.0.414

The release notes say the dose calculator was removed to meet App Store rules.

Estimated level charts
No1

Profiles list half-lives; there is no modelled level chart.

Yes14

Estimated medication levels and timing.

Metrics and progress4 features
Metrics and progress: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Weight and body metrics
Yes1
Yes14
Progress photos
Yes (free: up to 2)1
Yes14
Journal or symptom check-ins
Yes1

Journal check-ins with mood, energy, sleep and symptoms.

Yes14

Symptoms with severity and timing, mood, energy, sleep and daily check-ins.

Injection-site rotation
In the apps, not on the web4
Yes14

Interactive body map.

Nutrition and wellness1 feature
Nutrition and wellness: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Nutrition tracking
No1
Yes14

Calories, macros, fiber, water and photo meal scans.

Community1 feature
Community: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Community
Discussions free; Q&A with Pro131
Yes14

Community groups and polls.

Integrations4 features
Integrations: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Apple Health
Yes6

Reads weight and body fat; never writes.

Yes14

Activity data sync.

Health Connect (Android)
Yes6

Reads weight and body fat; never writes.

Not advertised
Wearables
No1

No Oura, WHOOP or Apple Watch app.

Yes14

Apple Watch app.

Home Screen widgets
iPhone only4

Home Screen and Lock Screen widgets ship in the iPhone app; Android has none yet.

Yes14

Home Screen widgets and Live Activities.

AI1 feature
AI: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
AI assistant
No1

No AI in the app. A public, read-only MCP server lets AI assistants look up library profiles.

Yes14

Arlo answers general educational questions.

Data, sync and privacy3 features
Data, sync and privacy: Peptide Library compared with Pep AI
FeaturePeptide LibraryPep AI
Multi-device sync
Pro (free Android accounts sync most data)1
Yes14

Synced to the account.

On-device storage
Yes46

The apps keep data on the device; account sync is optional.

Not advertised

The listing says data is synced to the account.

Data export
Pro1
PDF reports14

Want research, vendor prices and tracking in one place? Peptide Library has a free plan.

Try Peptide Library freeExplore the research library

The difference

What makes Peptide Library different?

  • Wellness routine or research workflow

    Pep AI ties shots to nutrition, hydration, symptoms, sleep and mood. Peptide Library ties your log to cited research, inventory planning and vendor prices.

  • Tracking on a free plan

    Pep AI's listing says a paid subscription is required for its tracking features. Peptide Library's free plan includes logging, schedules, reminders, the journal and body metrics.

  • AI in the app

    Arlo answers general educational questions inside Pep AI. Peptide Library has no in-app AI; its public research profiles can be read by AI assistants through a read-only MCP server.

  • Calculators

    Pep AI's 4.0.4 release notes say its dose calculator was removed to keep the app on the App Store. Peptide Library's calculator is on Android and on the website.

These pieces work together: read a profile, compare vendors on price per mg, add what you bought to inventory, and every logged dose updates your stock, calendar and journal.

Research

Research library: a reference platform or a tracking companion?

Pep AI's current US description doesn't describe a compound library; its research help comes from Arlo, which answers general educational questions about peptides and GLP-1s, and from in-app help articles.

Peptide Library's 200+ profiles cite PubMed, ClinicalTrials.gov, DailyMed and EMA sources and label studies by evidence type. The Research Intelligence Center adds publication and trial statistics, and you can compare peptides side by side.

Browse the 200+ research profiles · See the Research Intelligence Center

Tracking

Tracking, scheduling and inventory workflows

Both apps log shots and doses, give each item its own schedule and reminder times, and rotate injection sites on a body map. Pep AI adds a daily timeline, links symptoms to your dose history and estimates medication levels.

Peptide Library adds on/off cycles and titration in its schedules, and an inventory that deducts stock as you log and forecasts run-out and reorder-by dates. Pep AI organises vials with photos, but its listing does not describe stock forecasting.

Both track weight and progress photos. Peptide Library's journal covers mood, energy, sleep and symptoms; Pep AI covers those and adds nutrition and hydration.

Vendors

Vendor and pricing research

Pep AI doesn't advertise vendor listings or price comparison. If you buy research compounds and want to compare sources, Peptide Library's Shop lists vendor offers by compound and form, with price per mg after coupon codes and vendor profiles with reviews.

  • Compare listings

    Offers grouped by compound and product form, never mixed across forms.

  • Price per mg

    Unit prices after any vendor coupon code, from what the listing shows.

  • Vendor profiles

    Reviews, coupons and the shipping details a source supports.

About vendor listings. Vendor listings, prices, reviews, coupon codes and commercial partnerships are not independent proof of a product's purity, safety, legitimacy or suitability for human use, and a listing is not an endorsement. Peptide Library does not sell peptides. Some vendor links are affiliate links; affiliate status never changes the order vendors appear in.

Compare vendor prices · Browse the vendor directory

Screens

Inside Peptide Library

Screens from Peptide Library on the web and in the app. We don't show Pep AI's screens; see its store listing for those.

  • Peptide Library body metrics on iPhone: weight, body fat, fat mass and lean mass with 90-day trends
    Body metrics with trends, next to your logs.
  • The Peptide Library calendar on iPhone with every scheduled entry this month logged
    A calendar of what was logged and what is next.
  • Peptide Library inventory on iPhone with low-stock and reorder alerts and run-out dates
    Inventory with uses left, run-out dates and reorder alerts.
  • Peptide Library tracker on iPhone with today’s scheduled entries and a 31-day streak
    Schedules, reminders and a daily log with streaks.

Pricing

Pricing: Peptide Library vs Pep AI

Pep AI is free to download, but its listing says tracking requires a paid subscription; the App Store lists $9.99 a month and yearly plans from $29.99 to $59.99. Peptide Library's free plan includes tracking, and Pro is $4.99 a month, $39.99 a year or $89.99 once.

Pricing in US dollars, checked October 25, 2026
PlanPeptide LibraryPep AI
Free accessFree1

Library, vendor prices, logging, schedules, journal and metrics are free. Inventory is limited to 1 peptide.

Free download14

The listing says a paid subscription is required to use the tracking features.

Monthly$4.9921$9.9914
Annual$39.9921$29.99–$59.9914

Several yearly prices are listed.

Lifetime$89.9921Not listed
ModelFree plan; Pro subscription or lifetime purchaseSubscription required for tracking
  • US prices, checked October 25, 2026. Store prices vary by country and change; the price shown in each app before purchase is the one that applies. Check official pricing before you subscribe.
  • Peptide Library: US prices. App Store and Google Play prices are set per country and shown in the app before purchase.
  • Pep AI: App Store In-App Purchases list several yearly prices; the price you see is shown in the app.

Fair is fair

Where Pep AI wins

  • Nutrition with photo meal scans

    Calories, protein, carbs, fat, fiber and water, with quick log, saved meals and estimated macros from a photo. Peptide Library does not track nutrition.

  • Symptoms linked to doses

    Log nausea, fatigue and appetite changes with severity and timing, and see them against your dose history.

  • Apple Watch and an AI companion

    A redesigned Watch app, Live Activities and Arlo for general questions.

  • Reports for your provider

    PDF reports that pull nutrition, sleep, side effects and progress together.

Who it suits

Who should use which app?

  • You take a GLP-1 and track food and symptoms daily

    Pep AI

    Nutrition, hydration and symptoms are the core of the app.

  • You research several peptides

    Peptide Library

    Cited profiles, comparisons and research statistics.

  • You want to track without paying

    Peptide Library

    Tracking is part of the free plan.

  • You want AI and an Apple Watch app

    Pep AI

    Arlo and a Watch app are built in.

  • You compare vendors before buying

    Peptide Library

    Vendor listings and price per mg by product form.

Final verdict

The verdict on Peptide Library vs Pep AI

Pep AI is the better fit for a GLP-1 routine centred on food, hydration and how you feel. Peptide Library is the better fit when you research peptides, manage stock and compare vendors, and want to start without a subscription.

The two don't compete for every user. Peptide Library's research pages and vendor prices are free on the web without an account, so you can use them next to any tracker.

Get the Peptide Library app, or start on the web without an account.

Try Peptide Library freeBrowse vendor prices

FAQ

Pep AI vs Peptide Library: common questions

Is Pep AI free?

It's free to download, but its App Store listing says a paid subscription is required for the tracking features. Plans are listed at $9.99 a month and $29.99 to $59.99 a year (US, checked October 2026).

Does Pep AI still have a dose calculator?

No. The 4.0.4 release notes say the calculator was removed to keep Pep AI on the App Store. Peptide Library's calculator is on Android and the website.

Which app is better for GLP-1 nutrition tracking?

Pep AI. It tracks calories, macros, fiber and water, with photo meal scans. Peptide Library doesn't track nutrition.

Does Peptide Library have an AI assistant like Arlo?

No, there is no AI in the app. AI assistants that support MCP can look up Peptide Library's public research profiles through its read-only MCP server.

Is Pep AI available on Android?

Yes. Pep AI: GLP-1 Peptide Tracker is on Google Play from Zode Development. Neither listing mentions a web app; Peptide Library also works in a browser.

Can I use Pep AI and Peptide Library together?

Yes. Peptide Library's library, research pages and vendor prices are free on the web without an account, so they work alongside any tracker.

Explore More Than Peptide Tracking

Research peptides, organize your tracking, manage inventory, and compare vendors in one place.

Get Peptide Library for iOSGet Peptide Library for AndroidExplore Peptide Library on the Web

Free plan available. Pro adds unlimited inventory, sync on every device, export and more; see Free vs Pro.

Peptide Library app icon

Peptide Library

By Superfime LLC

Pep AI app icon

Pep AI

By Zode Development (pepaiapp.com)

Pep AI: GLP-1 Peptide Tracker is developed by Zode Development LLC (pepaiapp.com).

Sources

Store listings and developer websites as read on the date shown. Competitor details can change after that date.

  1. 1.Peptide Library Free vs Pro (Peptide Library, read )
  2. 2.Peptide Library pricing (Peptide Library, read )
  3. 3.Peptide Library and Tracker on the App Store (Apple App Store, read )
  4. 4.Peptide Library and Tracker on Google Play (Google Play, read )
  5. 5.Install the Peptide Library web app (Peptide Library, read )
  6. 6.Peptide Library privacy policy (Peptide Library, read )
  7. 7.Peptide Library research profiles (Peptide Library, read )
  8. 8.Research Intelligence Center (Peptide Library, read )
  9. 9.Peptide Trends (Peptide Library, read )
  10. 10.Peptide vendor directory (Peptide Library, read )
  11. 11.Compare peptide prices and vendors (Peptide Library, read )
  12. 12.Peptide calculator (Peptide Library, read )
  13. 13.Peptide Library community discussions (Peptide Library, read )
  14. 14.Pep AI: GLP-1 Peptide Tracker on the App Store (Apple App Store, read )
  15. 15.Pep AI: GLP-1 Peptide Tracker on Google Play (Google Play, read )

Disclosure and method

Peptide Library publishes this comparison and has a commercial interest in helping you evaluate its platform. Competitor features and pricing are reviewed using publicly available information: App Store and Google Play listings and each developer's own website, read on . We identify situations where another app may be a better fit.

We did not install or test competitor apps for these pages, and we don't score or rank them. A feature no source mentions is shown as "Not advertised", never as missing. App names and icons are trademarks of their respective owners, used only to identify the apps; Peptide Library is not affiliated with or endorsed by them.

Spotted something out of date? Tell us and we'll check it against the developer's sources. Corrections follow our editorial policy.

Research and educational use only. Not medical advice. Peptide Library does not sell peptides.