Best Apps to Track GLP-1 & Muscle Loss (2026)

The best app to track GLP-1 and muscle loss together is the one that treats body composition as a core feature, not an afterthought, because losing weight and losing muscle are two different problems. For muscle preservation specifically, you want fat-vs-muscle data, a protein target, and resistance-training logging connected in one place, so a falling number means something. As of 2026, that narrows the field quickly: most GLP-1 apps log doses well, but only a few build the muscle side in, and they make different tradeoffs.

This guide compares the apps that get closest, names what each does genuinely well, and is honest about where each one stops. Features and pricing change, so treat this as a starting map and confirm the details on each app's current App Store listing before you decide.

Why most GLP-1 apps miss the muscle problem

Here is the gap. GLP-1 medications like Ozempic/Wegovy (semaglutide) and Mounjaro/Zepbound (tirzepatide) drive real weight loss, and a meaningful share of that lost weight can be lean mass rather than fat. Synthesizing across trials, research suggests roughly 25% to 40% of the weight lost on GLP-1 medications can come from lean mass, with tirzepatide trials nearer the lower end and some semaglutide trials closer to 40%. ("Lean mass" on a scan includes water and organ mass, so it is not all skeletal muscle, but a real share is.)

That means the scale is the wrong instrument. A scale reports total mass, so a pound of lost fat and a pound of lost muscle look identical to it. To know which tissue you are losing, you need an app that separates fat mass from lean mass and watches the trend. We cover the underlying science in GLP-1 and muscle loss: the complete guide and the at-home tells in fat loss vs muscle loss on GLP-1.

Most GLP-1 trackers were built around the injection: log the shot, rotate the site, note side effects, watch weight drop. That is genuinely useful, and several apps do it beautifully. It just is not the same job as protecting muscle, which needs three data streams working together: a body-composition reading, your protein intake, and your resistance-training stimulus.

How we compared these apps

We scored each app on the axes that actually matter for muscle preservation, not on dose logging alone (almost every app handles dose logging, so it is a weak differentiator here). The axes:

• Body-composition tracking: can it record and trend fat mass and lean mass, not just weight?
• Muscle-loss trend analysis: does it interpret that body-comp data, for example by flagging a lean-mass downtrend, rather than only storing numbers?
• Protein targets: does it set a protein goal and track against it?
• Resistance-training logging: can you log strength sessions in the same app?
• Dose logging, free tier, and price: the table-stakes context, included for completeness.

We drew on public App Store and official-site information as of 2026. Where a capability is not documented publicly, we mark it "not confirmed" rather than assuming it is absent. This is a fairness rule, not a hedge: an app may add features after this was written.

The comparison table: muscle and body-composition features

Read this across, not down. Several of these apps are excellent at their core job; the table is specifically scored for the muscle-preservation use case, which is a narrower question than "is this a good app."

Feature (muscle-preservation lens)	Myo	Phaze	Shotsy	Generic macro app (e.g. MyFitnessPal)
Body-composition tracking (fat vs lean mass)	✓ Fat-vs-muscle split; syncs smart scale, DEXA, InBody	✓ AI body-comp estimate (beta) + DEXA import + lean-mass trending	limited: logs body-fat and lean-mass numbers	✗ Tracks weight only, no lean mass
Muscle-loss trend analysis	✓ Muscle-loss trend flag on lean-mass data	limited: lean-mass trending shown; muscle-loss flag not confirmed	limited: stores numbers; analytical trend flag not documented	✗ None
Protein targets	✓ Calculated target + daily coaching	✓ Protein-first nutrition logging	✓ Logs protein (cals/protein/water)	✓ Strong macro/protein tracking
Resistance-training logging	✓ In-app strength logging	✗ Not listed as of 2026	✗ Not listed as of 2026	limited: some log exercise calories, not structured lifts
GLP-1 dose logging	✓ Sites, dates, missed-dose marker	✓ 14+ medications, PK levels	✓ Broad med list, polished UX	✗ No dose context
Platforms	iOS	iOS (Android listed on site, verify)	iOS + Android	iOS + Android
Free tier	✓ Free for 1 medication	✓ Free tier (limited)	✓ Free tier (limited)	✓ Free tier (limited)
Price (as of 2026)	$6.99/mo, $39.99/yr, $99.99 lifetime	$4.99/mo, $34.99/yr	~$9.99-19.99/mo, ~$39.99-59.99/yr	varies; ~$19.99/mo premium typical

Cells marked "not confirmed" or "not listed" reflect what is publicly documented as of 2026, not a claim that the feature can never exist. Verify current listings.

Phaze: the closest body-composition peer

Phaze (by Zeit Capital) is the app to beat on the body-composition axis, and it deserves real credit for it. It bills itself as a complete GLP-1 tracker covering 14 or more medications, and on the muscle side it does something most GLP-1 apps do not: it offers a body-composition feature (in beta) that includes an AI photo estimate of body-fat and muscle (stated accuracy around plus or minus 3 to 5 percentage points), plus DEXA scan import and lean-mass trending. That is a genuinely strong, body-comp-aware feature set, and if importing your DEXA results and watching lean mass over time is your priority, Phaze is a serious choice. It also handles PK estimated levels, protein-first nutrition logging with AI photo, barcode, and voice input, lab tracking, progress photos, and a shareable clinical PDF, on a free tier plus a Pro plan at $4.99 per month or $34.99 per year.

Where Phaze differs from Myo is the training side. Resistance-training logging is not listed in Phaze's public feature set as of 2026, and resistance training is the single strongest lever for keeping muscle in a deficit. So Phaze can show you that your lean mass is moving, and even import a DEXA to prove it, but it does not log the workouts that are supposed to defend that lean mass. That is the honest distinction: Phaze is excellent at measuring body composition; Myo connects that measurement to the training and protein behaviors that change it. If you already train and log lifts elsewhere, Phaze's body-comp tooling may be all you need.

Shotsy: a polished tracker that now logs body metrics

Shotsy (by Aja Beckett) is one of the most popular and well-built GLP-1 shot trackers, with a large, active community and a clean, focused experience across iOS and Android. It covers a wide medication list (Ozempic, Wegovy, Mounjaro, Zepbound, Rybelsus, Saxenda, Trulicity, plus compounded and custom), handles dose logging, side effects, weight, and injection-site rotation, and offers estimated GLP-1 level (PK) charts and nutrition tracking (calories, protein, water) on its premium tier. It earns its popularity.

Importantly, and to be fair to it, Shotsy recently added the ability to log body fat, lean body mass, waist circumference, and blood glucose. So it is no longer accurate to say Shotsy "doesn't track body composition." The honest distinction is between logging a number and analyzing it. Shotsy lets you record a lean-mass figure; what is not documented as of 2026 is an analytical engine that flags a muscle-loss trend, correlates lean mass against your protein and training, or imports a DEXA or InBody scan to ground the number. Resistance-training logging is also not listed. So if you want a mainstream, beautifully made GLP-1 tracker with a strong community and the option to record body metrics, Shotsy is a great pick; if you want those body metrics interpreted as a muscle-preservation signal, that is where Myo's approach differs. Check Shotsy's current App Store listing, since it has been actively adding features.

Generic macro apps (MyFitnessPal and similar)

Macro trackers like MyFitnessPal are worth naming because many GLP-1 users already have one, and for what they do, they are excellent. MyFitnessPal has one of the largest food databases anywhere, reliable barcode scanning, and accurate protein tracking, which matters a lot, because hitting protein is the highest-leverage muscle-preservation habit on a GLP-1. If your only goal is to count protein, a macro app does it well, on both iOS and Android.

The limits are structural, not a knock on the product. A general macro app tracks weight but not lean mass, so it cannot separate fat loss from muscle loss. It has no GLP-1 dose context, so it cannot relate your appetite or intake to your dose week. And while it logs that you exercised, it is built around exercise calories, not structured resistance-training progression. For a GLP-1 user trying to protect muscle, that leaves the two most important data streams (body composition and training stimulus) outside the app. You can bridge the gap by pairing it with a body-composition tool, but then you are stitching together what an integrated app gives you in one place.

Myo: muscle as the organizing principle

Myo (by PixelPort LLC) is built muscle-first, and that framing is its honest differentiator. Where the other apps treat body metrics as one feature among many, Myo organizes around the question "are you keeping your muscle?" and connects the data streams that answer it: a fat-vs-muscle body-composition split (syncing a smart scale, DEXA, or InBody), a muscle-loss trend flag that watches your lean-mass direction, a calculated protein target with daily coaching, and in-app resistance-training logging, all sitting next to your dose log. That integration (body comp plus protein plus training, interpreted together) is the thing no single competitor above currently combines. We walk through the same idea, tool by tool, in body composition tracking on a GLP-1.

Myo is iOS only as of 2026, which is a real limitation if you are on Android (Regimen, Shotsy, and Pep AI all support Android; see our broader roundup in the best GLP-1 tracking apps compared). On pricing, the free tier covers one medication with dose logging, a missed-dose marker, an injection-site map, weight, side effects, daily check-ins, manual protein, fiber, and water rings, Apple Health sync (never paywalled), and data export. Premium ($6.99/mo, $39.99/yr with a 7-day trial, or $99.99 lifetime) adds multi-medication, medication-level PK curves plus a personal "Your Body's Curve," the fat-vs-muscle tracking and muscle-loss trend flag, doctor-ready PDF and CSV reports, side-effect correlation charts, a supply and vial tracker for compounded users, a food database with barcode and photo and voice logging, the resistance-training logging and protein coaching, a titration and microdose planner, widgets, and iCloud sync. Myo is a tracking and education tool, not medical advice, and it is not affiliated with any GLP-1 maker.

How to choose the right muscle-tracking app for you

Start from your constraints, not the feature lists. A few honest decision rules:

• If you are on Android, Myo is out for now, so look at Shotsy (mainstream, logs body metrics) or, for body-comp depth, confirm whether Phaze's Android version is live on its current listing.
• If your priority is importing DEXA results and trending lean mass, Phaze and Myo are the two strongest. Choose Phaze if DEXA import and AI body-comp estimates are the core feature you want; choose Myo if you also want resistance-training logging and protein coaching wrapped around that data.
• If you mostly want a polished, popular shot tracker and body metrics are a nice-to-have, Shotsy is hard to beat on community and UX.
• If you already love your macro app for protein, keep it, and add a dedicated body-composition tracker so you are not blind to lean mass.
• If you want one app that makes muscle the point (fat-vs-muscle, a trend flag, protein coaching, and lifting in one place, free for one medication), that is the niche Myo was built for.

Whatever you choose, the rule that matters more than the app is consistency: pick one body-composition method, log it regularly, and watch the trend rather than any single reading. We compare the measurement methods themselves in how to track muscle loss on a GLP-1, and the protein targets in how much protein on a GLP-1. The best app is the one you will actually open every week.

References

Lean-mass share of GLP-1 weight loss (range across trials): STEP 1 DXA analysis (semaglutide), Journal of the Endocrine Society, 2021, derived from Wilding et al., New England Journal of Medicine; SURMOUNT-1 DXA substudy (tirzepatide), Diabetes, Obesity and Metabolism, 2025, doi 10.1111/dom.16275.

Phaze features and pricing: phaze.fit official site and App Store listing, as of 2026 (body-composition beta with AI estimate and DEXA import, PK levels, protein-first nutrition, Pro $4.99/mo or $34.99/yr).

Shotsy features and pricing: shotsyapp.com and App Store/Google Play listings, as of 2026 (dose logging, PK level charts, nutrition, and recently added body-fat, lean-body-mass, and waist logging).

MyFitnessPal features: myfitnesspal.com and App Store/Google Play listings, as of 2026 (food database, barcode scanning, macro and protein tracking).

Myo features and pricing: Myo by PixelPort LLC, App Store listing, as of 2026.

App features and pricing change frequently; confirm the current App Store or Google Play listing for each app before deciding.