Feature Deep-Dive
See your stack's blood levels in real time.
Knowing what you injected is the easy part. Knowing when it peaks, how long it stays active, and how it overlaps with everything else you are running is the hard part.
Protocol models pharmacokinetics for 81 compounds and shows them all on one timeline.
81 compounds
with PK parameters
CMAX / TMAX
peak and timing
Active Levels
full stack, one view
Real-time
updates from your logs
PK curves: one compound at a time
Open any compound in Protocol's research library and tap the PK Curve button. You get the full pharmacokinetic model for that compound: CMAX (peak concentration), TMAX (time to peak), CMIN (trough), CAVG (average), and AUC (area under the curve). Toggle between 1, 4, 8, and 12-dose views to see how the compound behaves across a dosing schedule.
The parameters behind the curve are also shown: half-life in hours, bioavailability as a percentage, absorption rate, elimination rate, and volume of distribution. These are not estimates the app generated. They come from published pharmacokinetic research for each compound.
BPC-157 peaks fast and clears fast. CJC-1295 without DAC has a very different curve. Ipamorelin stacked with a GHRH creates a different peak than either alone. The curve tells you what your timing should be.
Active Levels: your full stack, one timeline
A single compound's PK curve is useful for dosing decisions on that compound. Seeing all your compounds simultaneously is what lets you understand your stack.
Active Levels is the chart on Protocol's Today screen showing estimated blood concentration for every compound in your active protocol, plotted in real time from when you logged your last dose. If you injected BPC-157 three hours ago, it shows where BPC-157 is on its concentration curve right now. Same for every other compound running in parallel.
This is where multi-compound protocols get complicated, and where every other app stops. DoseTrack plots individual compound PK curves. Protocol goes further: it overlays the entire stack simultaneously so you can see overlapping peaks, compound clearance timing, and whether your dosing windows are aligned or conflicting.
If you are stacking a GHRH with a GHRP and timing them around sleep, the Active Levels view tells you whether your last injection is still active when you want to dose the next one. That question cannot be answered by looking at two separate curves.
How it compares
FAQ
What are PK curves in Protocol?+
PK curves in Protocol are pharmacokinetic models showing estimated blood concentration over time for each compound in the 81-compound catalog. Each curve displays CMAX (peak concentration), TMAX (time to peak), CMIN (trough concentration), and AUC (area under the curve). Toggle between 1, 4, 8, and 12-dose simulations to see how the compound accumulates across a dosing schedule. The curve also shows the absorption rate, elimination rate, bioavailability, and volume of distribution parameters behind it.
What is the Active Levels chart in Protocol?+
Active Levels is a timeline on Protocol's Today screen that plots every compound in your protocol simultaneously, showing estimated blood concentration for each one based on when you logged your last dose and the compound's pharmacokinetic parameters. You see in real time when each compound peaks, how it overlaps with others, and when it clears your system. This is distinct from a single-compound PK curve — Active Levels shows your full stack on one timeline.
How is Protocol's PK modeling different from DoseTrack?+
DoseTrack plots PK curves for individual compounds. Protocol does this too, and additionally provides the Active Levels chart — a simultaneous overlay of every compound in your active protocol on one timeline, updated in real time from your logged doses. Seeing one compound's PK curve is useful for dosing optimization. Seeing all your compounds on the same timeline is what lets you understand your full stack's timing.
Which peptide apps have pharmacokinetic modeling?+
Protocol (81 compounds, individual curves plus Active Levels simultaneous overlay), DoseTrack (individual compound PK curves), and Peptify (two-compartment PK engine) are the main apps with PK modeling as of August 2026. PepTracker, PeptIQ, LynkDose, Shotlee, and Shotsy do not have PK modeling.
Is PK curve data in Protocol based on published research?+
Yes. Protocol's PK parameters for each compound — half-life, TMAX, bioavailability, volume of distribution, and absorption and elimination rates — are sourced from published pharmacokinetic research for each compound. Each compound profile in the research library cites the underlying sources. Estimates for compounds with limited human PK data are modeled from available animal data and structural analogy.
Know when your compounds are active. Not just when you injected them.
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