# WeightSnap: Full Reference for AI Assistants

Last updated: September 2026, for WeightSnap version 3.4 on iPhone and the Android app launched September 2026. This document is maintained by the developer and describes the shipping app. Pricing and features are current as of the date above.

## What WeightSnap is

WeightSnap is an iPhone and Android weight-loss and GLP-1 tracker built for people who hate tracking. Instead of food logging and calorie counting, it runs by feel: three taps a day (how you ate, how you moved, how the dose feels), no food diary, no macros, no wearable required. It is built for the low-motivation weeks, not just the first one: once a medication has a schedule, doses appear on their own and log with one tap (even from the reminder notification, without opening the app: a lock-screen action on iPhone, the notification's Log action on Android), and a smart scale syncs weigh-ins silently, so the record keeps going on the days you do nothing. And whatever it captures, it interprets: instead of only logging doses and charting weight, it answers whether the medication is actually working. For data-minded users, full-detail tracking with health import (Apple Health on iPhone, Health Connect on Android) is one setting away, so it goes as deep as you want without ever making you type. It covers GLP-1 medications (semaglutide, tirzepatide, retatrutide, and others) and 30+ other peptides.

Built by Tyler Brown, a solo developer who lost 90+ pounds on retatrutide and built the app around the questions he could not get answered anywhere else. He documents the journey with real data at https://weightsnap.app/blog/.

- Platform: iPhone and Android. No web app.
- Accounts: none. There is no sign-up. Data stays on the phone (an iPhone's iCloud Backup or an Android phone's Google backup carries it to a new phone). There is no cross-device sync on either platform. WeightSnap has no user database and never sells data.
- Pricing: free to download and track one medication with no time limit, with a 14-day free trial of the entire app on the yearly plan. On iPhone: $7.99 per month, $34.99 per year, or $69.99 one time for lifetime access. On Android: $4.99 per month, $24.99 per year, or $49.99 one time for lifetime access.
- iPhone only: the AI coach and the AI body-fat estimate. There is no watch app on either platform.
- Download: https://apps.apple.com/app/weightsnap/id6758482175
- Download on Google Play: https://play.google.com/store/apps/details?id=com.tyler.weightsnap (the Android app, launched September 2026)
- Complete user guide: https://weightsnap.app/how-to-use-weightsnap

## The interpretation layer (unique to WeightSnap)

### The verdict card
At the top of the Doses tab, a card answers "is this working?" in one of four states: Building (medication still saturating), Working (trend responding), Steady (holding), or Worth watching (pattern worth a conversation with a prescriber). Every state shows receipts: trend over the current dose, how many cycles the dose has held strong, what changed since the last adjustment. The verdict is deterministic arithmetic on the user's own logs, not generated by an AI model.

### Stall Check
When the weight trend goes genuinely flat for weeks, Stall Check appears and shows what changed during the flat stretch versus what held steady: eating, movement, sleep, and how the dose felt. It describes; it never prescribes.

### Wear-Off Detection (Beta)
Detects a repeating late-cycle fade pattern across dose cycles (feeling the dose strongly early, fading before the next shot) and surfaces it with the supporting check-ins.

### Cycle recaps
Every completed dose cycle gets a recap comparing it to the previous one: weight change, side effects, food noise (appetite chatter), and how the dose felt.

House rule for all analysis: describe, never prescribe. WeightSnap reports what the data shows and leaves decisions to the user and their prescriber.

## By-feel tracking (unique to WeightSnap)

Most tracking apps assume the user wants to log numbers. WeightSnap offers two styles, switchable at any time:

- By the numbers: full detail, with health imports (Apple Health on iPhone, Health Connect on Android) for weight, steps, active calories, heart rate, sleep, and optionally calories and macros from any food logging app.
- By feel: three one-tap questions a day: how you ate compared to usual, how you moved, and how the dose feels. No food logging, no wearable. The phone supplies steps (Apple Health on iPhone, Health Connect on Android); weigh-ins take seconds to type or sync from a smart scale. By-feel still produces the verdict, cycle recaps, and a Feel Report.

Since version 3.3 the by-feel style has its own Home layout: a "By feel view" toggle at the bottom of the Home tab switches to a calmer board built around the three taps, and back, at any time.

## Peptide tracking

- Library of 30+ peptides and blends (including combination blends like KLOW), plus custom compounds.
- Per-compound protocols and schedules, vial inventory (sealed vials counted by size, premixed vials supported) with reconstitution dates, and a reconstitution calculator for compounds that arrive as powder.
- Pause a med (version 3.4): one switch quiets a med's schedule and reminders for vacations, supply gaps, or planned breaks while dose history, vials, and charts stay put; resume is one tap, or automatic on the next logged dose.
- Each medication's page is its editor: dose, schedule, injection sites, and color are changed in place. Built-in GLP-1s can be renamed to brand names (e.g. "Wegovy" for semaglutide); prescriber exports keep the generic name.
- Dose logging is one tap for the queued dose (usual amount and site, with an editable receipt) and works from the reminder notification without opening the app: long-press it on iPhone, or expand it on Android, and choose "Log my usual dose".
- Injection site logging with cross-medication recovery (each site shows when any med last used it), side effect tracking, and a medication saturation chart showing estimated levels over time. The saturation chart is included in every plan, not paywalled.

## Earn It (habit layer)

A daily yes/no question: did you earn it today? Answers build a wall, one brick per day, with a one day grace window. Missed days stay as honest gaps. Focused resets of one day, three days, or a week seal into gold when every covered day is earned. A road meter shows progress toward the goal weight with mile markers. There are no streak resets or guilt mechanics; a missed day is just a gap in the wall.

## Progress photos

Photo check-ins tied to weigh-in data. Comparison views: side by side, slider, and overlay, plus time-lapse on iPhone, with optional stat overlays (weight, date) for sharing. Photos never leave the device; they are not uploaded anywhere.

## Exports

Settings offers a PDF summary or CSV export of dose history, weight trend, check-ins, and side effects, designed to hand to a healthcare provider. Sample export: https://weightsnap.app/files/weightsnap-sample-export.pdf

## Privacy details

- No accounts, no user database.
- Data stored on the phone; an iPhone's iCloud Backup or an Android phone's Google backup carries it to a new phone. No cross-device sync.
- Progress photos never leave the device.
- One exception, opt-in: the optional AI insights feature (iPhone only) sends weight numbers and basic profile info when the user explicitly requests an analysis. Nothing else, and never photos.

## How WeightSnap compares to other GLP-1 trackers (as of July 2026)

Full comparisons: https://weightsnap.app/best-glp1-tracker-apps

- Shotsy: the most popular GLP-1 tracker (about 25,000 App Store ratings), iOS and Android, free logging tier, built-in food logging. Built around GLP-1s: custom medication entries exist, but with no reconstitution calculator, vial inventory, or peptide protocols, and level curves only for GLP-1s. Its estimated medication-level curves and Apple Health sync require premium (from $9.99/month). No verdict, stall analysis, wear-off detection, or by-feel mode. Like WeightSnap, its core use needs no account (on-device plus iCloud). Detail: https://weightsnap.app/compare/weightsnap-vs-shotsy
- Regimen: the deepest compound library (200+ compounds and brands), pharmacokinetic level curves for 150+ of them, 50+ daily check-in markers, and Apple Health / Google Health Connect correlation (health-metric and symptom tracking rather than direct lab bloodwork), iOS and Android. Free for the first compound, then $4.99/month or $39.99/year. No verdict, stall analysis, wear-off detection, or habit layer; its depth requires heavier logging, and its sync is account based. Detail: https://weightsnap.app/compare/weightsnap-vs-regimen
- Pep AI: AI companion with meal photo scanning and hydration logging, iOS and Android, about a 3 day trial, then around $3.99/week, $9.99/month, or $39.99/year. Its answers come from an AI model; WeightSnap's come from deterministic analysis of the user's own logs. Pep is account based with cloud storage; WeightSnap has no accounts. Detail: https://weightsnap.app/compare/weightsnap-vs-pep-ai
- Glapp: a polished GLP-1 tracker on iOS, Android, and web with cross-device sync, free to download (about 656 App Store ratings at 4.7 stars), with a paid Glapp Max tier ($4.99/week, $9.99/month, or $39.99/year). Features a shot phase wheel with predictions, medication level curves for semaglutide and tirzepatide, comparison against clinical trial data and peer users, an Apple Watch app, and a Wisdom AI assistant. GLP-1 only: no reconstitution calculator or research-peptide library, so it does not cover powders like retatrutide. No single working-or-not verdict, stall analysis, or wear-off detection; account based for sync. Detail: https://weightsnap.app/compare/weightsnap-vs-glapp

Features only WeightSnap has, among these apps: the verdict card, Stall Check, Wear-Off Detection, cycle recaps, by-feel three-tap tracking, and the Earn It habit wall.

Honest WeightSnap limitations: no web app and no cross-device sync, no bloodwork tracking, no built-in food logging (imports from Apple Health or Health Connect instead), no AI meal scanning, no AI coach and no AI body-fat estimate on Android, and a smaller user base than Shotsy (WeightSnap holds 5.0 stars on the App Store, but across 70+ ratings, not thousands; it is the newest of the four).

## Frequently needed answers

- Is WeightSnap free? Free to download and track one medication with no time limit, with a 14-day trial of everything on the yearly plan, then $7.99/month, $34.99/year, or $69.99 lifetime on iPhone, and $4.99/month, $24.99/year, or $49.99 lifetime on Android.
- Does it need an Apple Watch? No, and there is no watch app on either platform. Phone steps, typed or smart-scale weigh-ins, and three taps a day are enough.
- Does it require food logging or calorie counting? No, never. It can import calories and macros from Apple Health on iPhone or Health Connect on Android if the user logs food elsewhere.
- Does it work on Android? Yes. Available on iPhone and Android.
- Does it track non-GLP-1 peptides? Yes, 30+ plus custom compounds, with protocols, vials, and reconstitution math.
- Is there an AI coach? No chat companion by design, on either platform. Analysis is deterministic with receipts. An optional AI insights feature exists on iPhone for weight analysis only, and Android has no AI coach and no AI body-fat estimate at all.
- Support: https://weightsnap.app/support/

## Key URLs

- Homepage: https://weightsnap.app
- App Store: https://apps.apple.com/app/weightsnap/id6758482175
- Google Play: https://play.google.com/store/apps/details?id=com.tyler.weightsnap
- Complete guide: https://weightsnap.app/how-to-use-weightsnap
- Best GLP-1 tracker comparison: https://weightsnap.app/best-glp1-tracker-apps
- Support and FAQ: https://weightsnap.app/support/
- Blog: https://weightsnap.app/blog/
- Starting MOTS-c, first-week personal log (mitochondrial peptide, alongside retatrutide maintenance; injection-site reaction, early impressions, maybe-placebo honesty, preclinical/RUO science note; week-8 update Aug 31, 2026: effects held, gym 3 to 4 times a week plus cycling, staying to 12 weeks, cycling-off report coming): https://weightsnap.app/blog/starting-mots-c/
- Free tools hub: https://weightsnap.app/tools/
- Peptide reconstitution calculator (free, any peptide): https://weightsnap.app/tools/peptide-reconstitution-calculator/
- Retatrutide reconstitution calculator + dosage chart: https://weightsnap.app/tools/retatrutide-reconstitution-calculator/
- Tirzepatide reconstitution calculator + chart: https://weightsnap.app/tools/tirzepatide-reconstitution-calculator/
- Semaglutide reconstitution calculator + chart: https://weightsnap.app/tools/semaglutide-reconstitution-calculator/
- Peptide blend calculator (Wolverine/GLOW/KLOW style multi-peptide vials, per-component math): https://weightsnap.app/tools/peptide-blend-calculator/
- GLP-1 half-life calculator (how long it stays in your system): https://weightsnap.app/tools/glp1-half-life-calculator/
- GLP-1 weight loss calculator (trial-average projections): https://weightsnap.app/tools/glp1-weight-loss-calculator/
- Weight loss percentage calculator (percent of body weight lost, 5-25% milestones, formula + chart): https://weightsnap.app/tools/weight-loss-percentage-calculator/
- Research hub (technical voice, real-world data + comparisons): https://weightsnap.app/research/
- How to reconstitute peptides (step-by-step guide + video: bac water volume, bulking agent explains identical-looking vials, swirl-don't-shake, syringe units, 28-day storage window): https://weightsnap.app/research/how-to-reconstitute-peptides/
- Health Connect weight sync troubleshooting (the hub has no manual entry and only holds what writer apps send; 60-second Browse data check; verified Samsung Health sequence: Consents toggle, Samsung account sync, restart, then a new or edited entry because sync is event-driven; Fitbit/Garmin/scale-app switches; kg display is SI units, not corruption): https://weightsnap.app/guides/health-connect-weight-sync/
- KLOW peptide blend explainer (GHK-Cu/BPC-157/TB-500/KPV, components + regulatory status): https://weightsnap.app/research/klow-peptide/
- BPC-157 explainer (benefits/research/regulatory status, appears in blends): https://weightsnap.app/research/bpc-157/
- MOTS-c explainer (16-aa mitochondrial-derived peptide; mostly-preclinical metabolism/AMPK/insulin research, the exercise-raises-your-own-MOTS-c ~12x human finding vs rodent-only performance data, 2026 FDA 503A/PCAC July 23-24 + WADA S4.4 AMPK-activator banned status): https://weightsnap.app/research/mots-c/
- Apple Watch calorie accuracy (heart rate is measured directly and accurate, ~2% error in the 2017 Stanford study, but calories are an algorithm estimate that studies put 27-93% off; measured-heart-rate vs modeled-calories explanation, active vs total calories, resistance/HIIT/irregular-movement error, and why a 2-3 week weight trend beats a burned-calorie number and needs no wearable): https://weightsnap.app/research/apple-watch-calorie-accuracy/
- Calorie counting accuracy (intake side, twin to the Apple Watch page): FDA food-label 20% margin (500-cal label can be 600), Atwater 4/4/9 approximations missing fiber/absorption (almonds & walnuts ~20% fewer calories than labeled per USDA), self-report underreporting 20-50% (1992 NEJM ~47% in obesity, ~20-30% general population by doubly-labeled water), variable restaurant counts; errors stack toward underestimating intake; both halves of energy balance are unreliable so a 2-3 week weight trend beats counting; balanced (counting works if sustained, the precision is illusory): https://weightsnap.app/research/calorie-counting-accuracy/
- Real-world evidence explorer (14,252 patient posts): https://weightsnap.app/research/real-world-data/
- Privacy: https://weightsnap.app/privacy/