A peptide tracker records an injectable routine so the history is reliable: the amount you drew, when, where, and from which vial. Pepti adds the arithmetic — reconstitution, draw volume and syringe units — and keeps everything on your iPhone with no account. It records the figures you already have; it never tells you what dose to take.
By Tessaro Pty Ltd, the maker of Pepti · Reviewed
This page explains what a peptide tracker does, what is worth logging, and how to choose a peptide tracking app that fits the way you actually dose. It is written by the maker of Pepti, so treat the Pepti-specific parts as a description of our own app; the general advice holds whichever tracker you pick.
Get Pepti on the App StoreA peptide tracker has three jobs, and most of the value is in doing all three in one place. The first is to capture each injection as it happens: the amount drawn, the date and time, the site, and the vial it came from. The second is to do the arithmetic that a vial-based routine demands — turning a vial and the water you added into a concentration, then into a volume to draw and a count of syringe units. The third is to show the shape of things over time: how much is left in the current vial, where your last few injections landed, and how your weight or bloodwork is trending alongside the routine.
Done on paper, those three jobs drift apart. The arithmetic gets redone from memory, the site rotation becomes a guess, and the vial runs dry on a day you cannot reorder. A tracker’s real contribution is not any single screen; it is that the record, the maths and the trend all refer to the same underlying log, so a question like “which site did I use last Tuesday, and how much was left in the vial?” has one answer instead of three half-remembered ones. Pepti is built to be that single log, and nothing it shows you is medical advice — it is a measurement and record-keeping tool.
You do not need to record everything, but a few fields do a lot of work. The point of logging is that the record can answer questions later that memory cannot, so the fields worth keeping are the ones a future question will turn on.
Reconstitution sounds technical, but it is a couple of divisions. The concentration of a reconstituted vial is simply the amount of peptide in it divided by the millilitres of water you added. Once you know the concentration, the volume to draw for the figure you are working to is that figure divided by the concentration. Nothing about it is a judgement call once you have those two inputs — you read the peptide amount off the vial, you choose the water volume, and the rest is arithmetic.
concentration = peptide in vial ÷ water added volume to draw = your figure ÷ concentration syringe units = volume × 100 (U-100 syringe)
U-100 syringes are the common at-home type: marked from zero to one hundred units, where the full millilitre is one hundred units. That makes the last step a fixed conversion rather than anything to agonise over. Illustrative conversions only: if the calculator works out a draw of 0.1 mL, that is 10 units; 0.25 mL is 25 units; half a millilitre is 50 units. The numbers that matter are yours, and they come from your own vial and your own figure, not from this page.
The one trap worth naming: change how much water you add and every unit count you had memorised is wrong, because the vial has not changed but the concentration has. That is exactly why doing it by hand is error-prone and why a tool helps. Pepti’s reconstitution calculator does both divisions and the unit conversion for you and saves the result against the vial; the longer walk-through of what to draw sets out the same maths step by step. In the app and on both of those pages, the rule is the same: you supply a figure you already have, and the tool converts it — it does not choose it.
Injecting repeatedly into the same spot is the habit rotation exists to break, and the only way to rotate reliably is to know where the last one went. Pepti tracks a twelve-site scheme: six body regions — abdomen, thigh, deltoid, glute, love handle and tricep — each split left and right. It remembers your recent sites, shows which are due a rest, and points you at the next one, so rotation becomes something the record enforces rather than something you try to hold in your head. The standalone injection site rotation guide explains the scheme and the reasoning in full.
A vial is a small budget: a fixed amount of peptide, a fixed amount of water, and a number of injections before it is empty. Once you know your draw volume, the doses a vial holds is just the liquid in it divided by the volume per draw, and Pepti works that out when you reconstitute and counts down from it as you log. Attach what the vial cost and you also get a running cost-per-injection and enough warning to reorder before a vial runs dry mid-week. None of this requires you to re-derive anything — the same log that drives rotation drives the vial count.
Many people like to see the rise-and-fall pattern of a compound between injections rather than think of each one in isolation. Pepti can plot that curve from a reference half-life and the times you actually logged, so the chart reflects your real schedule. The half-life figures it draws on are the published, cited ones gathered on the evidence pages — semaglutide, tirzepatide and retatrutide — and the curve is a depiction of timing, not a prediction of how you will respond or a claim about results. It is there to make the cadence of a routine legible, nothing more.
Most trackers are built around an account and a server; the data lives with the company, and the promise about it takes the form of a privacy policy. Pepti takes the other approach by construction. There is no account and no sign-up, and your protocol and health data stay on the device. There is no cloud sync, with a single stated exception: if you use the optional AI coach, that one conversation is sent to Pepti’s server to produce a reply. Everything else stays on your phone, which means there is nothing held server-side for anyone to lose, sell or hand over. Both models can be run well and they fail differently; this is simply the one we chose, and we would rather state the exception plainly than imply there is none.
There is no universally best tracker, and anyone selling you one should make you suspicious. The honest way to choose a peptide tracking app is to decide which few things actually matter for how you dose, then pick the tool that gets those right. These are the criteria worth weighing.
| What to check | Why it matters | Where Pepti stands |
|---|---|---|
| Dosing stance | Whether the app suggests amounts or only records yours — a real editorial and safety difference. | Never suggests a dose; records the figure you already have. |
| Reconstitution math | Vial users need draw-volume and unit math; pen users never touch it. | Built in, with a free calculator on the site. |
| Supply form | Prefilled pens and compounded vials are tracked differently. | Built for vials and research peptides; logs pens too. |
| Privacy model | Account and cloud, versus on-device with nothing held server-side. | No account, on-device, apart from the optional AI coach. |
| Platform | An iOS-only app is no use on Android, and vice versa. | iOS only, iOS 17.2 or later. |
| Price and tiers | Free, freemium, or flat — and whether the feature you want is gated. | One flat tier, 14-day trial on annual, nothing gated. |
| Cited evidence | Whether reference claims link to a source you can check. | Evidence pages cite their sources with PubMed links. |
Read those against your own situation and the answer usually falls out. If you inject from prefilled pens, a pen-oriented tracker will fit you better than ours and you should use it. If you are on Android, you need a cross-platform app, which Pepti is not. For the actual field, we keep a disclosed comparison of ten peptide tracker apps, and three head-to-heads — Pepti vs Regimen, Pepti vs Dose Track and Pepti vs Shotsy — where every claim about another app is dated and tied to a public source. Those pages name names; this one deliberately does not, so nothing here goes stale against a competitor’s next update.
A peptide tracker app is a record-keeping tool for an injectable routine. It stores what you did and when - the amount you drew, the time, the injection site, and which vial and lot it came from - so the history lives in one place instead of in your memory or on a notepad. Pepti also does the reconstitution and draw-volume arithmetic for you, converting figures you already have into a volume to draw and syringe units. It never decides anything medical for you.
At minimum, log the amount you drew, the date and time, and the injection site. Recording the vial and its lot number as well means that if a batch is recalled or a vial behaves oddly, you can see exactly which injections came from it. Pepti keeps all of this on a single timeline, so the record reads as a sequence rather than scattered notes, and your weight and bloodwork can sit on the same timeline.
A calculator answers one question once: how much to draw right now. A tracker keeps the answers over time - every draw, every site, every vial - so you can see your rotation, how much is left in a vial, and the trend in your weight or bloodwork alongside it. Pepti includes the calculator and the record in one app, so the figure you work out is saved rather than recalculated from scratch each time.
No, nowhere, by design. You enter a figure you already have and Pepti does the arithmetic around it - the volume to draw, the syringe units, and the number of doses left in a vial. It never suggests, recommends, or calculates what that figure should be. That is a decision for you and whoever directs your care, and Pepti stays on the measurement side of that line.
Yes. Pepti has no account and no sign-up, and your protocol and health data stay on the device. There is no cloud sync, with one stated exception: if you use the optional AI coach, that conversation is sent to Pepti's server to generate a reply. Nothing else leaves your phone, and there is nothing held on a server for anyone to lose, sell, or hand over.
No. Pepti is iOS only and requires iOS 17.2 or later. If you are on Android, our comparison pages point to trackers that ship an Android app, so you can find one that fits your phone rather than buying the wrong tool.
There is no single best one - the right choice depends on how you dose. If you use prefilled pens, a pen-oriented tracker fits best. If you reconstitute from vials, you need built-in reconstitution and draw-volume math. If you are on Android, you need a cross-platform app. If privacy is the priority, choose one that keeps data on the device without an account. Pepti is built for people drawing from vials on iPhone who want the math built in and their data kept local. Our ten-app comparison and the head-to-head pages lay out those trade-offs so you can judge against your own priorities.
Pepti is $16.99 per month or $69.99 per year in USD, with a 14-day free trial on the annual plan. There is one tier and no free version: every feature is included, with nothing gated behind an upgrade, no ads, and no data selling.
If you draw from vials, track on iPhone, and want the arithmetic built in and your data kept on the device, Pepti is built for exactly that. If one of those is not you, the comparison pages above will point you somewhere better — that is the honest use of this page.
Get Pepti on the App StoreThis page describes record-keeping and measurement. It does not recommend any compound, dose, or schedule, and Pepti provides no dosing guidance on any page.
Not medical advice. Pepti is a record-keeping and measurement tool, not a medical device.