GLOSSARY

Triiodothyronine (T3) is a thyroid-hormone form with prominent receptor activity.

The thyroid axis uses hypothalamic and pituitary signals with hormonal feedback. Total hormone, free fraction and peripheral conversion are different measurements. Deiodinases support activation or inactivation; reverse T3 is not active T3. Illness, medicines and energy insufficiency can affect results. Sluggishness or a single result does not establish hypothyroidism, and thyroid hormone is not a tool for self-directed athletic weight manipulation; interpretation requires the full clinical and laboratory pattern.

Hormonal axes use feedback and often pulsatile and time-dependent patterns. A rise can be compensatory and a decline temporarily adaptive, neither diagnosing disease without context. Hormone ratios depend on numerator, denominator, timing and units. Sports nutrition does not aim to maximize every hormone; the practical goal is adequate supply and appropriate physiological responses, evaluated with health and performance rather than an isolated ratio or peak.

Synthesis, storage, secretion, transport and clearance are distinct processes. Blood concentration reflects entry and removal rather than directly measuring secretion; exercise-related plasma-volume changes can also affect it. Half-life depends on hormone form and method and is not identical to the duration of all effects. Comparisons therefore need sampling time, previous food and recent activity standardized or recorded rather than interpreting isolated concentration differences without context.