Paraxanthine for Anaerobic Performance
Current human evidence does not show that paraxanthine on its own improves anaerobic performance such as sprint or peak power output. The two small trials that tested it found no significant effect, so any benefit remains unproven.
Why this grade7-layer evidence engine
This claim is graded Weak (Tier C) and flagged as disputed because only two very small human RCTs have tested paraxanthine for anaerobic endpoints, and both were null. In a 12-person crossover (PMID 38725238), paraxanthine did not improve Wingate peak or mean power after a 10-km run versus placebo or caffeine. In a 14-person rowing trial (PMID 41918248), paraxanthine alone again showed no significant benefit; only the caffeine-plus-paraxanthine arm was faster (p=0.044, d=0.30), suggesting the signal comes from caffeine synergy rather than paraxanthine itself.
The one strongly positive study (PMID 35215543) was in mice, where 4 weeks of supplementation raised grip strength (+17%) and treadmill endurance (+39%). That is a chronic animal model that does not translate to acute human anaerobic power, and like the human trials it was industry-funded by the patent holder, the basis for the conflict-of-interest flag. There is no systematic review or meta-analysis on this endpoint.
Authoritative bodies offer no support. EU EFSA treats synthetic paraxanthine as an unauthorized novel food with no approved health claims, the UK position is effectively against (it cannot be lawfully sold as a food supplement in Great Britain), and WHO has not addressed it. Mechanistically it acts as an adenosine A1/A2A antagonist like caffeine and appears relatively safe, but its safety is not fully characterized. NIH ODS, Mayo, Cleveland Clinic and Harvard are all silent, which is an absence of evidence, not an endorsement.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.446
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 1 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status