The absorption window is the span of time during which a compound is actually being taken up across the gut wall, distinct from the dose window that describes when intake is logged.
Why it matters for logging
A log entry records when a dose is taken, not how long the gut takes to move that dose into circulation. When two compounds compete for the same transporter, or when food changes gut motility, the actual uptake span can run longer or shorter than the user expects. Confusing the intake moment with the absorption span can make two seemingly identical days produce different readings.
What shapes the absorption span
Several factors change the width of the window.
- Compound class, since transporter-limited nutrients can have narrower absorption spans than passively absorbed ones.
- Gastric transit time, which shifts with food volume, fiber, and fluid.
- Co-ingestion patterns, since shared transporters split available uptake between competitors.
Interaction with dose timing
A short absorption window aligns closely with the intake moment. A wide window can spread effect across hours. Treating logged dose windows as if they were absorption windows often produces false attribution when a compound has slow uptake.
Practical action step
When stacking minerals or other transporter-limited compounds, note in the journal whether a dose was taken near a competing compound or a meal that changes transit.
Relation to other concepts
The absorption window pairs with bioavailability and dose-curve concepts to describe both how much of a label reaches circulation and over how long that uptake occurs.
Uncertainty and limits
- Absorption span estimates come from controlled studies that may not reflect real meal patterns.
- Transporter competition is well documented for some nutrients and poorly mapped for many others.
Cross-site references
How this appears in Unfair
Unfair uses absorption-window class data to flag competing compounds and to widen the comparison window when an effect is expected to appear hours after a logged dose.
Clinical safety note
If absorption changes after a new compound is added, hold escalation and review co-ingestion and meal context before changing amount.