Log dose calculations

PepRally stores and plans peptide amounts in micrograms (mcg). When you log a dose against a reconstituted vial, we also reason about liquid volume and—on mobile—a U-100 insulin syringe scale as a volume reference. This page documents that math for transparency. For research record-keeping only; verify all measurements independently.

1. Dose amount (canonical unit)

Logged doses use doseMcg in the API and the Log Dose amount field in the app (submitted with unit mcg).
Cycle peptide default weeklyTargetDoseMcg is a weekly total (mcg per protocol week), not a single injection size.
Per-week overrides store another weekly total for a specific protocol week.
Each scheduled slotuses that week's total divided by how many injection days fall in that week for your frequency.
Milligrams (mg) are only shown as a convenience: doseMg = doseMcg / 1000.

2. Suggested amount when logging (mobile)

Vial mix math gives concentration, not how many mcg to log. The suggested log amount is always a per-injection figure, in priority order:

Planned vial dose — plannedDoseMcg on the cycle–vial link when it matches the vial you select.
Weekly total ÷ shots this protocol week— same rule as the server scheduler: that week's mcg total (override or default weekly target) divided by the number of due days in that protocol week for your frequency.

3. Vial concentration after reconstitution

After reconstitution, the vial stores peptide mass quantityMg (mg), bacteriostatic water bacWaterMl (mL), and computed concentration concentrationMcgMl (mcg per mL of solution).

concentrationMcgMl = (quantityMg × 1000) / bacWaterMl

Volume-based helpers need a positive, non-null concentrationMcgMl. If the vial is not reconstituted, that value is absent and syringe-unit estimates cannot be computed.

4. Liquid volume for a dose

The volume of solution that contains your dose (in mL) is the dose in mcg divided by concentration in mcg/mL. The API uses the same relationship when reducing remainingMl on the vial for a logged dose.

mlDrawn = doseMcg / concentrationMcgMl

5. U-100 insulin syringe “units”

On a U-100 insulin syringe, the barrel is graduated so that 100 units = 1 mL of liquid (1 unit = 0.01 mL). PepRally uses that scale only as a geometric volumereference for drawing reconstituted peptide solution—not as “insulin drug units.”

u100Units = mlDrawn × 100

// equivalently:
u100Units = (doseMcg / concentrationMcgMl) × 100

PepRally shows that product as-is (draw volume in mL times 100). That matches the U-100 scale where 100 units span 1 mL from zero; values above 100 mean more than 1 mL on that scale.

Actual lines on syringes, dead space, and technique vary. Treat any in-app number as a starting point for your own records, not as a guarantee.

Research hub · Cycles, stacks & terminology

Where this is implemented

Mobile helpers and the Log Dose screen card live in the PepRally codebase; server-side concentration and mlUsed when logging are computed in the API vial and dose services. Technical contributors should keep the in-repo reference doc in sync when formulas change.