Education
Blood Testing & Biomarkers
How to make sense of the blood markers behind nutritional status — what common tests measure, what the numbers mean, and when a result actually warrants action.
Numbers are only useful with context
Blood tests can turn a vague question — "am I deficient?" — into something measurable. Markers for vitamin D, ferritin, B12, HbA1c and others give a far more reliable picture than symptoms or guesswork.
But a reference range is not a treatment plan. Results are shaped by recent illness, inflammation, hydration and lab methodology, and "normal" is not always the same as "optimal" for every marker or every person.
The guides in this section explain what each common biomarker reflects, how to interpret typical ranges, which factors distort them, and when a value is a reason to change diet, supplement or see a clinician — rather than a reason to panic.
Browse the blood-testing library
Every guide is evidence-based. Refine by supplement type, goal, evidence strength and common concerns.
Blood testing articles
Guides on interpreting biomarkers and nutritional blood tests.
Evidence guides are on the way
We're building this section carefully — each guide goes through the same evidence-grading and safety review as the rest of Supplete. New articles will appear here as they're published.
Explore Supplement Facts →