Product
Features
PepCycle is a log and a unit converter for people who manage their own peptide and GLP-1 protocols. Below is everything it does, grouped by the part of the workflow it belongs to — and each entry says why it exists, because most of them come directly from a recurring complaint about existing trackers.
Last updated
Logging
The entry screen is where a tracker lives or dies. Ours is built so that an honest entry is faster than a dishonest one.
Backdating as a first-class action
Set any past date and time. Vial contents, adherence figures and next-due dates all recalculate — they do not go stale. Most abandoned logs die here.
Why backdating matters →Skipped is as easy as taken
Marking a dose skipped takes the same single tap as marking it taken, and no streak punishes you for it. A log that rewards fiction is not a health record.
Every route, not just injections
Injection, oral, nasal and topical entries each show the fields that actually apply. A nasal spray is not an injection with the wrong labels.
Nasal peptides →Full edit history
Any entry can be corrected. Deletion exists for genuine mistakes — duplicates, wrong compound — not for tidying away inconvenient truths.
Vials & compounds
Enter the vial once, correctly, and every entry afterwards is two taps.
No vial-size ceiling
Enter 2 mg or 1,000 mg. A 50 mg cap — common in this category — cannot represent a GHK-Cu or NAD+ vial at all.
Why 1,000 mg vials exist →Blends as one vial with components
A three-peptide vial is one compound with three components. One volume drawn, three per-component amounts derived — not three fake vials you maintain in parallel.
Blends vs stacks →Editable reconstitution
Corrected the diluent volume? Edit it. Contents recalculate rather than forcing you to delete the vial and lose its entries.
The arithmetic →Two expiry clocks, both tracked
The printed expiry and the in-use window that starts at first puncture. Only the second one depends on your own record, and it is usually the binding constraint.
Storage & expiry →Lot, supplier and provenance
Batch numbers, supplier, received date and reconstitution date per vial — the fields that make an old entry interpretable.
Automatic countdown
Remaining contents update as you log, including backdated entries, with a notification before a vial runs low.
Vial duration calculator →Schedules
Weekday checkboxes cannot express every-3-days. We model intervals instead.
Every-N-day intervals
Any integer interval, projected across a real calendar with its weekday drift visible rather than hidden.
Why weekly trackers break →On/off cycling
Defined periods on and off, repeating from a start date, rather than a list of dates you maintain by hand.
Titration plans
Enter the plan your prescriber gave you as scheduled future changes, then log what actually happened against it. The plan and the history stay separate objects.
Titration tracking →Per-compound schedules
A stack where one compound is every other day and another is weekly is entirely ordinary. Each keeps its own rhythm; the calendar shows them together.
Explicit anchoring
When an entry is late, you choose whether the next due date shifts with it or stays anchored to the plan. Neither is wrong — hiding the choice is.
Reminders that allow honesty
Every notification offers taken, skipped and snooze. A reminder whose only easy action is 'done' trains you to lie to your own record.
Schedules you can see
The calendar shows the whole shape of a protocol — intervals, breaks, titration steps and every compound at once — rather than a flat list of what is due today.
Sites & observations
Structured data you can actually summarise, instead of free text nobody can count.
Visual body map
Select the site by tapping rather than typing. Recently used areas are shaded, so the next choice is obvious instead of a memory test.
Site rotation →Structured site values
A fixed set of regions and sub-regions means 'left abdomen' is one value, not four spellings — which is what makes rotation reviewable.
Fixed side-effect items
Choose a small set of items and a severity scale, recorded at a consistent time — including the zeros, which are what give the rest a denominator.
Recording side effects →Measurements on a schedule
Weight and other measures recorded on a fixed cadence, so the trend is comparable rather than opportunistic.
Rotation without a memory test
Rotation fails on recall, not intention. Shading recently used areas turns the next choice into something you can see rather than something you have to remember.
Try the free rotation planner →Your data
No account, no server holding your log, and a complete export whenever you want it.
On-device storage
The log lives in a local database on your iPhone. There is no PepCycle account and no PepCycle server that stores your health entries.
The full data model →Your own iCloud sync
Sync runs through your personal iCloud private database. New phone, same Apple ID, same history — and we never see any of it.
Complete CSV & JSON export
Not a summary: compounds, vials with concentrations, blend components, every entry and every observation. Complete enough to rebuild the record elsewhere.
Export & backup →Versioned schema migrations
App updates migrate your database forward rather than replacing it. 'The update lost my history' is the failure this exists to prevent.
Works fully offline
Flights, foreign networks, no signal — logging never depends on a connection, because nothing has to reach a server.
What PepCycle deliberately does not do
- Suggest a dose, schedule, protocol or product. The converter does arithmetic on numbers you enter. It has no opinion about them, and it never will. Our position.
- Use the word “AI”. Nothing here is a model guessing at your health. Every number is deterministic arithmetic you can check by hand.
- Sell where to buy anything. No vendor links, no affiliate codes, no sourcing advice.
- Hold your data on our servers. There is no PepCycle account and no PepCycle database of health entries.
- Beg for a review. Not in the first two weeks, and not in the middle of anything.
Frequently asked questions
Does PepCycle work for both research peptides and GLP-1 pens?
Yes. Format is a property of each compound: a lyophilised vial shows mass, diluent volume and derived concentration; a pre-filled pen shows product, strength and first-use date with no reconstitution fields at all. Both sit in one timeline.
Is there a maximum vial size?
No. Enter the mass printed on your label, whether that is 2 mg or 1,000 mg. Vial-size ceilings are a common limitation in this category and they make GHK-Cu and NAD+ impossible to represent.
Can I log a dose from two weeks ago?
Yes. Any entry can be created or edited with a past date and time, and vial contents, adherence and next-due dates all recalculate accordingly rather than going stale.
Does the app tell me what dose to take?
Never. The converter performs arithmetic on values you enter, exactly like a calculator, and no feature suggests, recommends or adjusts a dose. All dosing decisions belong to you and your healthcare provider.
Do I need an account?
No. There is no sign-up, no email and no password. Your data lives on your device and syncs through your own iCloud account.
Log it once, keep it forever
PepCycle turns the numbers on this page into a running record: every dose, vial, site and side effect in one place — stored on your iPhone and backed up to your own iCloud.
Free to download · No account required · Price shown before you enter anything personal