TF
TF transferrin / HBB hemoglobin — the molecular target that 1 compounds in the wiki act on.
In one line: The iron-carrier protein — iron is what lets your blood carry oxygen.
TF (transferrin) ferries iron through your blood to where it's needed — above all, to build haemoglobin, the molecule in red blood cells that carries oxygen. Low iron means gasping endurance and constant fatigue, long before it shows up as anaemia — common in menstruating women and endurance athletes.
Crucial safety note: never supplement iron without testing first, because too much iron is toxic and damages organs. Test, then treat.