Fructosamine

Specialist

also glycated serum protein

What it isWhen blood glucose binds to circulating proteins (mostly albumin), it forms fructosamine. Because those proteins turn over every two to three weeks, fructosamine captures a shorter glycemic window than A1c.

DoesActs as a short-window mirror of average blood sugar.

GoodLow fructosamine confirms stable, low-amplitude glucose handling in the recent weeks.

BadElevation flags recent hyperglycemia and is especially valuable when A1c can't be trusted — pregnancy, hemolytic anemia, hemoglobin variants, blood transfusions.

Standard

200–285 µmol/L.

Optimal

200–230 µmol/L (lower is good)

Modifiers

Falls in hypoalbuminemia (artifact); rises in protein-loss states; vitamin C supplementation can interfere.

How to optimize

Lifestyle: Resistance training, Zone 2 cardio, sleep, and post-meal walks all move it within weeks.
Diet: Whole-food low-glycemic eating; cut sugar and refined grains.
Supplements: Berberine (500mg 3×/day), inositol (2g 2×/day), magnesium glycinate (300mg/day).
Peptides: GLP-1 agonists (semaglutide, tirzepatide, retatrutide).
Drugs: Metformin, GLP-1 agonists, SGLT2 inhibitors.

within Blood Sugar & Metabolic