GLOSSARY

L-Carnitine L-Tartrate (LCLT) is a carnitine salt used in some supplementation studies; its formulation and studied outcomes need separate assessment.

Carnitine participates in transporting long-chain fatty-acid groups into mitochondria for oxidation. Supplying oral carnitine does not automatically increase muscle carnitine or cause body-fat loss, because uptake and the broader energy balance matter. Carnitine forms, co-ingestion strategies and study populations differ. A metabolic role should be separated from evidence for a particular supplement outcome. Increased fat oxidation, reduced soreness and improved performance are different claims, each needing relevant evidence rather than being inferred from the transport pathway alone.

Fat contributes to exercise energy through circulating fatty acids and intramuscular lipid stores. Greater fat availability, uptake or mobilization does not automatically mean a greater oxidation rate. Relative contribution and absolute rate are also different: the percentage can rise while total exercise demand changes. Oxidizing more fat during one session does not by itself establish greater long-term body-fat loss. Interpret the measured process, exercise intensity, diet and overall energy balance together.

Over a defined interval, a difference between metabolizable energy intake and energy expenditure changes stored body energy. This principle does not imply that daily scale weight directly reveals energy balance. Water, glycogen and gut contents also contribute to body mass. Intake and expenditure influence each other through behavior and physiology, so projecting the same daily deficit indefinitely creates unrealistic predictions. Interpret the energy equation together with its timescale and the composition of the tissues changing.

Absorption, distribution, metabolism and elimination determine how an ingredient reaches circulation and tissues. Plasma concentration does not directly establish muscle uptake or a useful performance effect. Half-life describes a concentration decline under defined conditions, while time to peak describes when a measured maximum occurs. Food, formulation, repeated use and individual physiology affect these processes. A faster or larger blood peak is therefore not automatically evidence that a formulation is better for the athlete's intended task.

A credible supplement claim needs relevant controlled evidence, an appropriate comparison and a meaningful outcome. Randomization, placebo control and blinding reduce different sources of bias but do not guarantee a useful result. Sample size, uncertainty, training status, sex, diet and protocol affect interpretation. A pooled estimate is not a promise to every individual. Mechanistic plausibility, a changed biomarker, exercise capacity and actual competition performance are distinct levels of information that should not be treated as interchangeable.

Supplement safety depends on ingredient, dose, duration, health status and other exposures. Natural origin does not guarantee safety, and absence of a reported adverse event in a small trial does not establish long-term safety. Medication interactions, pregnancy, age and kidney or liver disease can change the decision. Distinguish an event occurring during use from a causally established adverse effect. New or severe symptoms require stopping the suspect exposure and appropriate assessment rather than increasing the dose to overcome poor tolerance.