Background/Objectives: Recovery nutrition must restore near-term readiness without indiscriminately suppressing biological signals that contribute to repair and training adaptation. This review evaluates recovery–adaptation coupling (RAC) as a research framework and clarifies its contribution relative to established recovery, nutrient-periodization, and athlete-monitoring models. Methods: Targeted narrative searches of PubMed/MEDLINE, Scopus, and Web of Science were supplemented by Google Scholar citation tracking and backward and forward screening. Peer-reviewed English-language literature available through 31 May 2026 was considered. Human athlete studies, randomized trials, systematic reviews, meta-analyses, consensus statements, and position stands were prioritized; mechanistic evidence was used to explain pathways rather than to support stand-alone performance recommendations. The final cited corpus comprised 130 records. No formal risk-of-bias tool, certainty grading, PRISMA denominator, or quantitative pooling was used. Claims were instead identified as established practice (EP), context-dependent evidence (CDE), mechanistic rationale (MR), or RAC hypothesis (RH). Results: The most consistent applied support concerns adequate energy availability, distributed high-quality protein, carbohydrate restoration when recovery windows are short, and individualized fluid and sodium replacement. Evidence for polyphenol-rich products, curcumin, omega-3 fatty acids, and creatine is context- and product-dependent. Collagen or gelatin evidence is mainly mechanistic or pilot-level, while RAC recovery-pattern categories and multimodal monitoring rules remain unvalidated hypotheses. RAC differs from existing frameworks by jointly specifying the next athletic demand, dominant recovery bottleneck, possible adaptive cost of intervention, and response-verification plan. Conclusions: RAC should presently be interpreted as an evidence-organization and hypothesis-generation architecture, not as a validated predictive, diagnostic, or treatment algorithm. Prospective comparative studies are required before RAC-specific decision rules can guide individualized practice.

Background/Objectives: Recovery between exercise exposures is often framed as the rapid suppression of soreness, inflammation, oxidative stress, and fatigue, although the same perturbations may also initiate tissue repair and training adaptation. This review proposes recovery-adaptation coupling (RAC) as a decision framework for matching nu-tritional strategies to recovery bottlenecks while preserving adaptive signals. Methods: A mechanistic narrative synthesis integrated evidence on exercise-induced muscle dam-age, inflammation resolution, immune-redox regulation, muscle protein turnover, glyco-gen restoration, connective-tissue remodeling, micronutrient sufficiency, nutrient timing, individual variability, and recovery monitoring. Results: RAC links four tar-gets—damage attenuation, inflammation resolution, anabolic remodeling, and adaptive signal preservation—to the next athletic demand, the dominant recovery bottleneck, and the markers used to verify response. Nutritional strategies are interpreted according to context, dose, timing, and response phenotype. Conclusions: RAC is a heuristic decision architecture rather than a validated universal algorithm; it aims to restore readiness without indiscriminately suppressing the signals required for longer-term adaptation.

Nutraceuticals are evaluated as though efficacy were a stable ingredient property, although net value may vary with exercise stimulus, exposure schedule, recovery pressure, athlete state, and prioritized outcome. This structured narrative review integrates exercise-adaptation biology, pe-riodized sports nutrition, training-load and recovery models, precision nutrition, and human evi-dence for sport-relevant interventions. Searches of PubMed/MEDLINE, Web of Science, and Scopus were updated through August 2026 and supplemented by citation tracking. General efficacy was separated from direct evidence of timing, context, or state modification. Nutraceutical Periodiza-tion for eXercise (NPX) is an allocation layer applied only after safety, legality, product quality, and plausible efficacy are established. It defines four non-sequential functional win-dows—performance exploitation, adaptation-permissive signaling, restoration, and resili-ence—and separates intervention strategy, training context, athlete state, and outcome hierarchy. Four falsifiable propositions test context modification, temporal allocation, bottleneck/state de-pendence, and whole-policy utility. Despite limited direct evidence for most allocation rules, NPX converts compound-specific efficacy into prospectively testable decisions. Targeted allocation may improve athlete-centered outcomes or preserve them with fewer exposures, lower burden, or less harm than standardized evidence-based use. Prospective interaction and policy trials are needed to establish the value and boundaries of these rules.

Nutraceuticals are evaluated as though efficacy were a stable ingredient property, although net value may vary with exercise stimulus, exposure schedule, recovery pressure, athlete state, and prioritized outcome. This structured narrative review integrates exercise-adaptation biology, periodized sports nutrition, training-load and recovery models, precision nutrition, and human evidence for sport-relevant interventions. Searches of PubMed/MEDLINE, Web of Science, and Scopus were updated through August 2026 and supplemented by citation tracking. General efficacy was separated from direct evidence of timing, context, or state modification. Nutraceutical Periodization for eXercise (NPX) is an allocation layer applied only after safety, legality, product quality, and plausible efficacy are established. It defines four non-sequential functional windows—performance exploitation, adaptation-permissive signaling, restoration, and resilience—and separates intervention strategy, training context, athlete state, and outcome hierarchy. Four falsifiable propositions test context modification, temporal allocation, bottleneck/state dependence, and whole-policy utility. None of the allocation claims in the present evidence map met the criterion for direct NPX allocation evidence. NPX therefore formalizes hypothetical allocation rules rather than an established supplementation policy; proposed improvements in athlete-centered outcomes or equivalent outcomes with less exposure, burden, or harm remain to be prospectively tested against an explicitly defined active evidence-based comparator. Interaction and policy trials are needed to establish the value and boundaries of these rules.