Soluble Transferrin Receptor (sTfR)

Specialist

also —

What it isA fragment of the transferrin receptor that iron-hungry cells release into blood. The hungrier the body's tissues are for iron, the more sTfR appears.

DoesReports cellular iron demand independent of inflammation.

GoodMid-range sTfR signals balanced iron supply and demand.

BadHigh sTfR confirms iron deficiency even when ferritin is elevated by inflammation — the cleanest tool to disentangle these.

Standard

2.2–5.0 mg/L.

Optimal

2.5–4.5 mg/L (narrow target)

Modifiers

Not significantly affected by inflammation.

How to optimize

Lifestyle: —
Diet: Iron-rich foods if deficient.
Supplements: Iron bisglycinate if true deficiency confirmed.
Peptides: —
Drugs: IV iron for severe deficiency. --

within Iron