GLOSSARY

Vitamin D Supplement provides vitamin D for an assessed need or indication. Correcting deficiency differs from an ergogenic claim in an already sufficient athlete.

Micronutrient supplements are most clearly justified by a documented deficiency, inadequate intake or a defined clinical indication. Different salts contain different amounts of the elemental mineral, so tablet mass cannot be read as active mineral content. Iron decisions require assessment of status and context; unnecessary intake can be harmful. Calcium, magnesium, zinc and vitamin D also need attention to total intake and medication interactions. A product correcting a genuine shortfall serves a different purpose from an ergogenic supplement in a nutrient-replete athlete.

The dose refers to the amount of the relevant active ingredient, not necessarily the mass of powder or the number of scoops. A single dose, daily total and body-mass-relative dose describe different quantities. Larger amounts can increase adverse effects without improving performance. Loading, maintenance and acute timing are ingredient-specific strategies rather than universal rules. Check all products used together so that repeated ingredients do not create an unintended total intake.

For example, compare mineral products by the declared elemental amount rather than the total compound mass. A suspected shortfall should be assessed in context, including diet and relevant tests. Correcting a documented deficiency can be valuable, but that does not mean extra intake improves performance when the athlete's status is already sufficient.

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.

A supplement can address a defined nutrient shortfall, provide a convenient sports-food format or target a specific performance mechanism. These purposes require different evidence and assessment. A product is not necessary simply because it is marketed to athletes, and normal training fatigue does not identify a nutrient deficiency. Begin with the athlete's diet, health, training and practical constraints, then define the expected benefit, suitable outcome and stopping or review point before adding a product.

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.

Label accuracy, ingredient identity, potency, contamination control and manufacturing traceability are separate aspects of quality. A proprietary blend may conceal the amount of each ingredient, preventing comparison with research. A certificate of analysis applies to specified tests and samples, not every possible hazard. Verify the exact product and batch in an independent certification program when relevant. Good manufacturing practice and third-party testing can reduce certain risks without proving efficacy or guaranteeing that every batch is free of prohibited substances.