Supplements
Also known as: Dietary supplements
Dietary supplements are products intended to add nutrients or other bioactive substances to the diet in concentrated form. They include vitamins, minerals, amino acids, botanicals, and sport-performance ingredients sold as powders, capsules, tablets, liquids, gels, or bars. A supplement is a product category, not evidence that its contents are necessary, effective, or safe for a particular person.
Supplements can serve different purposes that should not be conflated. One may correct a documented nutrient deficiency, another may provide convenient food components such as a protein powder, and a third may aim for a direct performance effect. Evidence must match the exact ingredient, dose, formulation, population, and outcome. A change in a blood marker, cell-signaling pathway, or short laboratory test does not automatically establish better strength, muscle growth, health, or recovery over time.
Only a limited number of sport ingredients have reasonably consistent evidence for specific uses. Creatine monohydrate can support repeated high-intensity performance and resistance-training outcomes, while caffeine can improve selected performance measures when used appropriately. Neither is universally useful, and neither replaces training, sleep, adequate energy, or a suitable diet. Multi-ingredient boosters are harder to assess because their effects and doses may not match those of separately studied ingredients.
The NIH Office of Dietary Supplements performance fact sheet reviews evidence, adverse effects, and medication interactions ingredient by ingredient. "Natural" does not mean harmless. Duplicate ingredients across products, proprietary blends, stimulant combinations, allergies, and doses far above food intake can all increase risk. Vitamins and minerals can also cause harm when excess intake is chronic or acute.
Product quality is a separate question from ingredient efficacy. Labels can be inaccurate, and a product may contain undeclared contaminants or substances prohibited in sport. The IOC consensus statement on supplements and athletes recommends a risk-benefit assessment and highlights inadvertent doping risk. Independent, sport-specific batch certification can reduce that risk but cannot prove that a product works or eliminate all risk; under anti-doping rules, athletes remain responsible for what they consume.
A sensible decision sequence is to define the problem, check whether food and training practices already address it, examine evidence for the exact product, review dose and interactions, compare likely benefit with cost and risk, and test tolerability outside competition. Medical conditions, pregnancy, breastfeeding, medication use, and suspected deficiency warrant advice from a qualified clinician or sports dietitian rather than a generic supplement stack.