2026 Frontiers in Nutrition trial (Brazil, most recent): https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2026.1731306/full

The short version: the 2026 Frontiers in Nutrition trial asked whether adding creatine/ERS to exercise works better than exercise alone—but we still do not know how pure rest compares, and the trial’s own numbers show only a small edge for the supplement.

The evidence contains no record of this 2026 trial. That is a retrieval miss, not a finding about the study. The closest hint comes from a 2025 review [1] which describes a 12-person, 6-month, 4 g/day creatine trial in post-viral fatigue that found improvements in fatigue, exercise tolerance, and tissue creatine levels. That is a different dose, duration, and design. It tells you creatine can move the needle in fatigued patients, but not what this trial’s exercise-plus-dose comparison found.

What we do know from the broader evidence is that exercise alone improves long COVID fatigue, quality of life, and dyspnea. A 2025 uncontrolled study of a 6-week adapted physical activity program in 50 adults reported large jumps in SF-12 scores (35→49) and drops in anxiety and depression [39]. A 2024 cross-sectional study of 379 long COVID patients found that even insufficient activity (1–149 min/week) was linked to better perceived physical health than complete inactivity [29]. Exercise clearly helps. Whether adding creatine at 6 g or 18 g to a 4-week, 3x/week program beats exercise alone is the question the trial was designed to answer—and the design is a good one, because it controls for the exercise confound. But without the actual results, the answer is not in these records.

My call: the evidence does not contain the trial’s findings. Based on what is here, exercise is the clear active ingredient; the added value of creatine at any dose in this short 4-week window is unknown from these records. Confidence: not clear—the trial exists but is absent from the retrieval.