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The intelligent peptide app

Stop guessing. Start measuring.

Lose the weight. Keep the muscle. Watch the numbers. The peptide tracker built for body composition, bloodwork, and the cohort that keeps you honest — on Mounjaro, Ozempic, Wegovy, Zepbound, or compounded peptides.

Mounjaro Ozempic Wegovy Zepbound Compounded Tirz Compounded Sema Retatrutide Peptide stacks
Get started on the web Free · magic link · no card Coming soon to App Store Coming soon to Google Play
Eight features. Free forever. No paywall, no card, no catch.
SUMMER SPECIAL · THROUGH AUG 31 Cohort+ annual at $29.99/yr — locked in for life. After Aug 31, the durable rate is $39.99/yr.

FOR PEOPLE ON THE PROTOCOL

The weekly letter

One letter every Sunday. The pharmacology, the math, the cohort patterns. No ads, no pharma money.

9:41

Progress

Track, trend, compare. Inputs live in Tools.

PHASE IV · MAINTENANCE · DAY 22 · WK 29 ·
MOUNJARO 5MG
25% OF PHASE
LEAN MASS PRESERVED
89%
On track
−55.7 lbs total · 37.2 lbs fat lost
62% to 160 lbs tap for full chart ›
All caught up · Next shot Fri
COMPOSITION
89%lean kept
−55.7 lbs total · smart-scale data
SHOT PHASE
Cruise Phase
2d 13h until next shot
Feed
Tools
Progress
Me
Your Week 18 report is ready Maintenance Phase · Sun 9:00 AM
89%
Lean mass preserved vs. 71% cohort median · Wk 18

Pictured: Cohort+ analytics (lean mass, body composition, cohort percentile). Free covers shot logging, weight, journals, and basic cohort matching.

Never moves free features behind a paywall Never shows ads to paid users Never sells you medications Never sells your health data Cancel in two taps Never moves free features behind a paywall Never shows ads to paid users Never sells you medications Never sells your health data Cancel in two taps
Why Cohort, specifically

Built for your protocol

Mounjaro, Ozempic, Wegovy, Zepbound, compounded — each with its own dose schedule, phase math, and taper curve. Not "generic weight loss."

Compared to your cohort

Not Reddit anecdotes. The real distribution of where people on your medication, your dose, and your week actually land. You see where you sit on the curve.

A decision tool, not a diary

Phase rings, taper readiness, lean-mass preservation, off-ramp triggers. You don't log shots to remember them — you log them so Cohort can tell you what to do next.

No ads. No data sales. Ever.

We sell software, not your bloodwork. Free tier never gets walled off, Cohort+ never sees ads, and your data isn't a product anywhere on the back end.

Peptide tracking apps treat you like every other patient. You're not.

№ I

MyFitnessPal doesn't know what week 9 of Mounjaro looks like. Calorie counters were built for a different problem. The food noise question they can't answer is the only one that matters.

№ II

Your provider sees you for twelve minutes a quarter. Long enough to renew the prescription. Not long enough to catch a stall, a side-effect drift, or whether your body comp is moving the right direction.

№ III

Reddit is loud. But you can't tell who's actually fourteen weeks in on 5mg. Anecdotes from the loudest poster aren't a cohort. They're a story. You need the distribution.

Most peptide apps are diaries. Cohort is something else.

Always free. Forever. We mean it.
EIGHT CRITICAL FEATURES · NEVER PAYWALLED
01
Shot logging

Every shot, every site, unlimited. Phase tracking, side-effect logging, and dose history.

02
Weight tracking

Log it, chart it, see your trend line cut through the noise. Cohort overlay included.

03
Phase tracker

Launch · Rise · Peak · Cruise · Taper · Pre-Shot. Named phases, live countdown.

04
Med-level estimator

A pharmacokinetic curve based on your medication's half-life. The science behind the phases.

05
Community

Posts, comments, follows. Filter the feed by your dose, your week. Real people, real numbers.

06
Decision journal

Write the why before the outcome. Auto-prompted on dose changes and goal shifts — so the story doesn't rewrite itself later.

07
Sunday Reflection

Eight questions every Sunday. Your answers stay private; the cohort's aggregated patterns come back Monday.

08
Weekly recap

Every Sunday: your week in numbers — shots, weight, side effects, mood. One tap to read, one tap to share with your prescriber.

We don't paywall what was free. We don't add ads to free tiers. We don't change the deal in version 3.0.
Five of those, in depth
01
Your cohort, not just you

See where you fall on the same dose, in the same week.

This is the difference. Personal trackers tell you what you did. Cohort tells you what people exactly like you — same medication, same dose, same week — actually experienced. Filter by sex, age band, side effects, even starting BMI. The honest answer to "is this normal?", backed by real data.

"Found out my plateau at week 7 was the median experience. Stopped panicking. Kept going."

Weight loss · Week 9

FILTERED COHORT — 8,102 peers
30% 20% 10% 0%
MEDIAN −10.8 LB YOU −14.2 LB · P68
0 LB −5 −10 −15 −20+
MOUNJARO 5MG × WEEK 9 × F · 35–44 × + ADD FILTER
02
Built for compound users

Built from day one for compound users.

Recon calculator. Vial tracker. BAC water log. BUD tracking. If you've reconstituted a vial at midnight, eyeballed your unit count on a U-100 syringe, or wondered when your pharmacy's beyond-use date hits — we built this for you. Most peptide apps treat compound as an afterthought. We designed for it from day one.

And we'll never sell you medications. We're a tracker — that's it. No telehealth pivot. No pharmacy integration. No "personalized prescription" funnel quietly rolled out in a future update.

"Finally an app where 'I take 32 units of 10mg/mL' isn't a question that breaks the entire flow."

Reconstitution

Vial strength 10 mg
BAC water 2.0 mL
Target dose 2.5 mg
Syringe U-100
50 units
DRAW TO THE 50 LINE

Vial Inventory

V192%
V264%
V328%
V48%
Vial 03 · BUD 12 DAYS
Vial 04 · BUD 3 DAYS
Reorder by NOV 14
03
Shot phase tracking

Know exactly where you are between shots.

Launch → Rise → Peak → Cruise → Taper → Pre-Shot. Six named phases, mapped to the actual pharmacokinetics of your medication. A live countdown to your next dose. Suddenly the late-week appetite return makes sense — you're not failing, you're in Taper.

"I finally understood why day five always felt different. Now I plan my hardest workouts around Peak."
CURRENT DOSE
MOUNJARO 5MG
SHOT DAY
WEDNESDAY
CYCLE DAY
4 OF 7
NEXT DOSE
3D 14H 22M
LAUNCH RISE PEAK CRUISE TAPER PRE-SHOT CURRENT PHASE Peak DAY 3·5 OF 7 3D · 14H · 22M UNTIL NEXT SHOT
04
Weekly report, not just a log

Every Sunday, a named report. Your week, told back to you.

Not a CSV export. A story. Your stats, your check-in trends, your cohort ranking, the side effects that stuck and the ones that faded. Week 9. Week 12. Week 24. Each one named, archived, and ready when you want to look back at where you were.

"I read every Sunday like a letter. It's the only data about my body that ever felt like it was for me."
SUN · OCT 26
REPORT № 09

The Whoosh Week

−3.4LB
This week
−14.2LB
Cumulative
P68
Cohort rank
7/7
Check-ins
2.1L
Avg water
1EVT
Side effects

Energy · M T W T F S S

Ahead of 5,514 peers this week
05
Real posts from real weeks

A feed where every post
comes with a week number.

Not influencers. Not before-and-after grift. Real people, real weeks, real numbers. Filter the feed by your dose, your week, your medication — and read what people felt, lost, gained, struggled with. The community is the value. We just make it findable.

"I almost quit at week 5. The stall nearly broke me. If you're in a stall right now — keep going."
j
jordan · week 24
WEGOVY 1.7MG · 6H AGO
Milestone
Jordan, week 1 on Wegovy 1.7mg, 198 lb Before
Jordan, week 24 on Wegovy 1.7mg, 162 lb — 36 lb total loss After
−36 lb
Total loss
24 wks
Duration
−18.2%
Body weight

Halfway there. The first three months were brutal — nausea, fatigue, the food noise didn't stop until week 9. Now? Quiet. Almost too quiet.

s
sam · week 7
COMPOUND TIRZ 5MG · 1D AGO
"I almost quit at week 5. The stall nearly broke me. If you're in a stall right now — keep going.
1.4k me too 312 replies WEEK 4–8 tag

Four more things most peptide apps miss.

Quiet differentiators most users don't discover until week three. All included in Free. All built because the existing tools didn't.

Accountability buddy

An anonymous pair on your exact protocol.

Opt in once. Cohort matches you with one other person on the same peptide, in the same phase, with the same goal. Weekly check-ins. Anonymous handles only — no DMs leak outside the app, no real names ever shown. The thing Reddit can't be because it's too loud.

Free · Opt-in · Pairs reset on request
Decision Journal

Every dose change, with the reason you made it.

Each protocol shift — dose bump, food change, sleep intervention — gets one line of "why." Six months in, you have a single document that explains every meaningful inflection in your weight, side effects, and labs. Nothing else in this space records the why.

Free · Auto-prompted on dose / goal changes
Sleep × shot-day overlay

See why you sleep worse the night after a shot.

Connect Apple Health or Oura and your sleep duration + efficiency overlays onto your protocol calendar. Most users find shot-night-plus-one is consistently 30–60 minutes shorter. Naming the pattern is half of fixing it.

Manual entry · Apple Health + Oura sync (Cohort+)
Cohort Index

Aggregated weekly outcomes — your cohort, not Reddit.

Median weekly weight change by phase × peptide family, with a 30-user minimum per cell so cohort stats never reveal patterns tied to fewer than 30 real users. Set expectations from real cohort data instead of Reddit anecdotes. Cells below the floor stay hidden until the population catches up.

Anonymized · Aggregated · Never tied to a handle

Cohort+ — the metrics that decide how you age.

The eight features above are everything you need to track the peptide journey itself — and they stay free forever. Cohort+ is a different layer: the slow-moving longevity metrics that decide whether you keep the muscle, what your bloodwork is doing under the surface, and how your cardiovascular age is tracking. Body composition. Sixteen lab markers. Cardio age. The numbers your doctor wishes you brought in.

№ I
Muscle preservation

Don't just lose weight. Keep what matters.

LEAN MASS
62.4%
↑ 1.8% in 12 wks
BODY FAT
28.1%
↓ 4.2% in 12 wks
WATER
52.8%
stable

Body composition tracking — lean mass, body fat %, body water. Smart-scale data via Apple Health (Renpho, Withings, Eufy) or manual entry. Especially critical on GLP-1s, where losing muscle alongside the fat is the trap nobody talks about.

№ II
Bloodwork that matters

Sixteen markers. Plain English.

ApoB 82 mg/dL
HbA1c 5.3%
LDL-C 98 mg/dL
Fasting Insulin 6.2 µIU/mL
ALT 22 U/L

16 markers across atherogenic, metabolic, liver, kidney, and thyroid panels — ApoB, A1c, LDL, ALT/AST, fasting insulin, TSH and more. Each with optimal/borderline banding so you see at a glance what's drifting.

№ III
Cardio age

The longevity number people actually want.

CHRONOLOGICAL
42
CARDIO AGE
37
HRV58 ms
RHR54 bpm
VO₂ max42.1 mL/kg/min

HRV (SDNN), resting heart rate, and VO₂ max from Apple Watch combine into a single number — your cardiovascular age vs. your chronological age. The longevity metric that actually drives behavior.

№ IV
Peptide-aware lab interpretation

Every reading, in light of your protocol.

Each lab value gets a protocol-aware annotation, not a generic reference range. "Mild ALT bump — common in loading. Re-test in 6 weeks." The interpretation a peptide-literate clinician would write in the margin.

№ V
Advanced trend annotations

Weight history, annotated by your protocol.

Shot tick marks along the bottom edge. Dose-change vertical lines marked directly on the chart. Stalls and whoosh weeks line up against what you actually did — not just what the scale said.

№ VI
Steady-state PK chart

Your drug level, across every shot.

A multi-shot drug-level curve in Shot History with trough-window analysis. See when you're actually at steady state, when troughs are getting too low, and how dose timing is shaping the curve.

FREE
All eight critical features. Forever.
Shot logging, weight, phase tracker, med-level estimator, community, decision journal, Sunday Reflection, weekly recap. No ads. No paywall creep. No card on file required.
COHORT+ · MONTHLY
$9.99/month
Body composition · 16 lab markers · cardio age · peptide-aware lab interpretation · advanced chart annotations · steady-state PK. Cancel any time, in two taps.
COHORT+ · ANNUAL · SUMMER SPECIAL
$29.99/year $39.99
Through Aug 31 — sign up at $29.99/year and that's your rate for life, even after the durable price ($39.99/year) kicks in. Same full Cohort+ feature set either way. Works out to $2.5/mo at the summer rate.
§ IV The Pact PRIVACY · NON-NEGOTIABLE

Health data is dangerous in the wrong hands. We know whose hands.

Peptide users live with a particular kind of awareness — that this data, in the wrong database, becomes an underwriting decision, a premium hike, a denial. We've also watched this category do exactly the wrong things: paywall what was free, sell pharmacy services to captive subscribers, refuse cancellations. So we built the product around three commitments. Not aspirations. Architecture.

№ I

We never sell your health data.

Not to insurers. Not to data brokers. Not to advertisers. Not to "research partners." Not via "opt-out anonymous analytics" added to a release notes popup. We do publish anonymized cohort statistics — only at the segment level (5+ users per bucket, never tied to a handle) — and that's the only data of yours that ever shows up in public copy. Subscriptions paid by you are the only revenue model.

№ II

Your photos are encrypted and only yours.

Progress photos — the most sensitive thing you'll ever take of yourself — are encrypted at rest, served via short-lived signed URLs, and scoped to your account. Only you can see them. We never share them, never use them for training, never ship them outside Cohort.

№ III

Delete everything, any time.

One tap. In-app. No support tickets. No "we kept charging after you canceled" emails. We hold the data for 30 days (the recovery window for accidental taps) and then it's gone — backups included. Full instructions and what we keep (anonymized aggregates only) live on our privacy page.

Things people ask before they download.

Is this a replacement for my doctor?
No. It's the file you bring to your doctor. Your weekly recap is the read-aloud version; Cohort+ adds the monthly recap with the cover sigil, and a provider-format PDF export is on the roadmap — clinical layout, no marketing, ready for the chart.
Do you sell my data?
No. Not to insurers. Not to data brokers. Not to advertisers. Not to "research partners." Not via opt-out anonymous analytics. Subscriptions paid by you are the only revenue model. See § IV above.
Does Cohort work with compounded peptides?
Yes — and this is one of the things we do that nobody else does. Reconstitution calculator, BAC water log, vial inventory, BUD tracking, supply alerts, multi-peptide protocol manager. We won't sell you the peptides themselves. We're a tracker.
Does it sync with Apple Health?
Yes — sleep duration and efficiency from Apple Health (and Oura, via PAT). Two-way sync for weight + body composition is on the near roadmap.
Can I cancel or pause Cohort+?
Cancel any time, in-app, two taps. Pause any month — your data stays put. We don't make you call. We don't make you email. We don't ask "are you sure" five times. The button just works.
Is there a web version?
Yes — you're on it. The web app (cohort.fit) handles posting, the cohort feed, letters, weekly recap, and account settings. The iOS app — coming to the App Store soon — is where you'll log shots, log weight, and manage compound vials on the go. Android lands after iOS. We'd rather ship two great clients than three mediocre ones.
What about refunds?
Cohort+ has a thirty-day free trial. If you decide it's not for you within the trial, you're never charged. Beyond that: web purchases get a 14-day no-questions refund through Stripe; App Store and Google Play purchases follow Apple's and Google's respective refund policies.
What happens if I delete my account?
One tap from Dashboard → Settings → Account. We soft-delete immediately so your handle and posts disappear from the cohort, then a 30-day window holds the data in case you come back. After 30 days every record of you is permanently erased from our servers and from backups. Anything cached in the iOS app stays cached until you sign out of it.

Not influencers. Just people on the protocol.

Every quote is from a real Cohort member, used with permission. Anonymous handles only — that's the whole posture.

“I'd been logging weight in Apple Health for six months and still didn't know if my dose was working. Two weeks in Cohort and the trend was obvious. The dose step-up timing changed everything.”

@reservoir Titration · Tirzepatide · Month 4

“My prescriber asked for ‘a summary of how the last three months went’ before adjusting my dose. I handed him the Cohort+ monthly report. He skimmed it for thirty seconds and approved the change.”

@northpath Steady · Semaglutide · Month 7

“The cohort feed is the only place I've seen people talk about the week-eight stall honestly. Reddit is a lot. This is just people on the same arc as me, posting what worked.”

@plumstone Steady · Tirzepatide · Month 5

Start measuring.

People on the same medications, doses, and protocol weeks as you are already logging. The honest answer to "is this normal?" shows up after a few weeks of data — yours, and theirs.

Coming soon to App Store Coming soon to Google Play
Switching from another tracker? Start logging the next entry today. After ten readings, the chart starts telling a story.