Know Your Runway Before Your Protocol Hits Empty
Enter your vial size, dose, and injection frequency — this tool calculates your exact supply date and tells you precisely when to reorder so you never break your routine.
Peptide vials don't come with expiration warnings. There's no low-supply alert on your compounding pharmacy's checkout page. One day you're mid-protocol, two days from your next injection — and the vial is empty.
This calculator exists to close that gap. Enter your protocol details and it tells you two dates that matter: when your supply runs out and when you need to reorder — with enough buffer that the shipment actually arrives in time.
Why Tracking Your Runway Matters
For most people, the first time they think about supply planning is the moment they reach for the vial and realise it's empty. That moment — three days before your injection day, a week before the next shipment could arrive — is one of the most stressful points in any health protocol.
It matters because consistency is the whole mechanism. Whether you're running a weekly GLP-1, a daily BPC-157 protocol, or a TRT cycle, the compound only works the way it's supposed to when the doses arrive on schedule. Miss a week of semaglutide and your active level drops to near-zero before the next dose. Skip a few days of ipamorelin and the steady-state rhythm you've spent weeks building resets completely.
Compounding pharmacies face real supply delays. Shipping windows vary. And nobody sends a reminder when your last vial is halfway through. The calculation is simple — vial size divided by dose, multiplied by your dosing interval — but without a tool that shows you the actual calendar date, most people leave it as a mental estimate. Those estimates are almost always optimistic.
The Three Most Common Runway Mistakes
1. Forgetting to account for frequency. A 5 mg vial at 500 mcg per dose yields 10 doses. Daily dosing means 10 days. Twice weekly dosing means 35 days. The same vial, the same dose — completely different timelines.
2. Ignoring shipping time. Ordering on the day you run out is two weeks of gaps in a typical compounding pharmacy window. The reorder date this calculator shows is ahead of your runout date by your chosen buffer — so the replacement arrives before you need it.
3. Losing count on partial vials. If you've been using a vial for three weeks, your mental picture of how much is left is almost certainly off by a few doses in either direction. This calculator helps you check that estimate with actual math.
Track Tonight's Dose. Automate the Rest.
This web tool solves today's question: how long does this vial last? The Halflife — Peptide & GLP-1 Log app solves the ongoing question: is my entire protocol accounted for — right now, automatically, without me having to open a calculator?
There's a meaningful difference between these two things. The web calculator gives you a number once. The app gives you a live picture of your protocol — every compound, every vial, every upcoming dose — updating continuously without any extra input beyond logging your injection.
With the app, you don't need to remember to run the runway calculation. You don't need to update it when you open a new vial. You don't need to figure out how the math changes if you adjust your dose. The app handles all of it in the background, and it alerts you when a compound is running low — before you ever feel the pressure of an empty vial.
Halflife App vs Manual Tracking
Whether you're currently using a spreadsheet, a notes app, a basic calendar reminder, or just relying on memory — here's what changes when you move to the Halflife app for your full protocol.
| Feature | Halflife Labs App | Manual Tracking |
|---|---|---|
| Real-Time Level Tracking | ✓ Live decay curve for every compound — automatically updated from your injection log, showing active % at any moment | ✗ No visibility between doses — you know when you injected, not what's still active |
| Multi-Compound Stacking | ✓ All your compounds on one timeline — testosterone, peptides, GLP-1s, and longevity stacks visible simultaneously | ✗ Each compound tracked separately (if at all) — no unified view, no overlap awareness |
| Dynamic Runway Alerts | ✓ Automatic reorder reminders based on your actual dose history — adjusts if your protocol changes | ✗ No alerts — you only find out you're running low when you look, or when you run out |
| Stress-Free Setup | ✓ Log a dose in seconds — the app handles every calculation, curve, and alert automatically from that point forward | ✗ Manual recalculation required every time anything changes — dose, frequency, vial size, or protocol structure |
Frequently Asked Questions
How do I calculate how many doses are in my vial?
Divide the total peptide content of the vial (converted to mcg) by your dose per injection (in mcg). For example: a 5 mg vial contains 5,000 mcg. If your dose is 250 mcg per injection, that gives you 20 doses per vial. This calculator performs that conversion automatically — just enter your vial size in mg and your dose in mcg, and it shows you the dose count instantly.
When should I reorder my peptide or GLP-1?
You should reorder before your supply runs out, with enough lead time to account for shipping and any compounding delays. The "reorder by" date this calculator shows is your runout date minus your chosen shipping buffer — typically 7 to 14 days. If your reorder date is coming up within the next week, treat it as an immediate action item. Ordering even a few days early eliminates most supply-gap risk.
Why does injection frequency change my supply timeline so dramatically?
Because frequency determines how quickly you move through doses. The same 5 mg vial at 250 mcg per dose gives you 20 doses — but 20 daily doses lasts 20 days, while 20 doses at twice-weekly frequency lasts 70 days. A three-and-a-half-times difference from a single protocol change. This is why the frequency input matters as much as the dose or vial size: small changes in schedule have large effects on your supply window.
What happens if I run out mid-protocol?
Running out mid-protocol means missed doses, which disrupts the steady-state compound levels your body has built up over weeks of consistent injections. For long-acting compounds like semaglutide or tirzepatide, even a one-week gap can cause active levels to fall significantly. For short-acting peptides like BPC-157 or ipamorelin, a break interrupts the accumulation pattern and effectively restarts your protocol from the beginning. Consistent supply is one of the most controllable variables in any protocol — and this calculator exists to keep it controlled.
Disclaimer. This calculator provides mathematical estimates based on the vial size, dose, and frequency you enter. It does not account for reconstitution losses, draw accuracy, storage conditions, or other protocol-specific variables. Results are for planning reference only and do not constitute medical advice. All dosing decisions should be made in consultation with a qualified healthcare provider. The Halflife Labs Vial Runway Calculator is an educational tool — not a medical device.