Research Measurements
Biomarker
A measurable indicator of a biological state, used to assess health and treatment response.
A biomarker is an objectively measurable indicator of a biological process, pathological condition, or pharmacological response. In supplement research, key biomarkers include serum ferritin (iron status), 25(OH)D (vitamin D status), serum zinc, B12, folate, TSH (thyroid function), CRP/IL-6 (inflammation), cortisol (stress), and hemoglobin A1c (glycemic control). Surrogate biomarkers predict clinical outcomes but are not direct measures of benefit. For example, a supplement that improves serum vitamin D levels (biomarker) may or may not improve hair growth (clinical outcome). Changes in biomarkers are often used as primary endpoints in shorter supplement trials.