What does the reconstitution calculator actually do?
It's a unit conversion. You tell it how much peptide is in the vial and how much bacteriostatic water you added — that gives a concentration in mg/mL. It then converts the amount you want to draw into a volume, and into units on a U-100 insulin syringe, where 100 units = 1 mL. It does not decide anything for you.
Is this calculator really free?
Yes, and it stays that way. It runs in your browser, there is no signup and no limit, and nothing is sent to us or anyone else. You never have to install the app to use it. We put it here because working out units from a vial is the most-asked question in every peptide community, and a page that answers it is more use to people than a locked one.
Is the iPhone app free too?
PepCore for iPhone is a subscription app: $39.99 a year or $6.99 a month, each with a 7-day free trial. One subscription unlocks everything: protocols, reminders, the injection-site map, stats, vial and supplier tracking, backup, the built-in reconstitution calculator, the AI Coach, PDF and text reports, and protocol QR images. The calculator on this page is the exception and stays free on the web. There is no ad-supported version and we do not sell your data.
What happens when the free trial ends?
If you don't cancel, it converts to a paid subscription automatically and Apple charges the card on your Apple Account. If you cancel any time before the last 24 hours of the trial, you're not charged. Cancelling is in Settings → your name → Subscriptions, and it takes about four taps. Your data stays on your phone either way.
Why units instead of mL?
Insulin syringes are marked in units, not millilitres. On a U-100 syringe, 100 units = 1 mL, so 0.25 mL reads as 25 units. The calculator shows both.
Does the amount of bacteriostatic water change how much peptide I get?
No — it changes the concentration, not the total. More water means a larger volume for the same amount of peptide, which is easier to measure accurately on the syringe. Less water means a smaller, harder-to-read draw. The total in the vial is whatever the vial contains.
Is my data sent anywhere?
No. PepCore stores everything on your iPhone, encrypted at rest, with an optional Face ID lock. There is no account, no analytics and no tracking. The one exception is the AI Coach. If you use it, whatever you submit — including any lab, InBody or Whoop screenshot — is sent through our proxy to the AI provider to be analysed, and we do not store it. Our privacy policy sets that out in full. This web calculator runs entirely in your browser.
Is there an Android version?
Not yet — PepCore is iPhone-only for now. The calculator on this page works in any browser.
Does PepCore give dosing advice?
No, and it never will. It's a log and a calculator. It doesn't recommend compounds, amounts, schedules or combinations. Those are decisions for you and a qualified healthcare professional.
Important
PepCore is an educational reference and personal tracking tool for adults 18+. It does not provide medical advice, diagnosis, treatment, prescriptions or recommendations. Always consult a qualified healthcare professional before starting, changing or stopping any peptide, supplement, medication or protocol.
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