Paraxanthine
Also known as: 1,7-dimethylxanthine, PX
Two recent randomized, double-blind crossover trials administering oral paraxanthine (200 mg) evaluated cognition after a 10-km run and rowing performance plus sleep. Paraxanthine improved certain cognitive measures after prolonged exercise versus placebo and tended to produce better subjective sleep outcomes than caffeine, but did not show clear standalone ergogenic benefit for 2000-m rowing at the tested dose.
Last reviewed: 2026-10-14 · 2 indexed studies
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Overview
Paraxanthine is the primary human metabolite of caffeine and has been administered orally in recent randomized trials as a standalone agent and combined with caffeine. Human trials report modest acute cognitive benefits after intense exercise and suggest a more favourable subjective sleep profile compared with caffeine. Evidence for clear standalone ergogenic effects on endurance performance is limited.
Mechanism & Function
Mechanism of Action
Not directly evaluated in the provided abstracts. The ingredient was studied as an orally administered compound for acute cognitive and performance effects, but mechanistic details are not reported in these trials.
Physiological Role
Not specified in the supplied trials beyond assessment of acute central nervous system effects and subjective sleep measures following single-dose administration.
Primary Pathways
Performance / Health Relevance
Paraxanthine showed acute cognitive benefits after prolonged running and, in one small trial, when combined with caffeine produced a small improvement in rowing time trial performance; paraxanthine alone did not produce a clear ergogenic effect at 200 mg in that rowing study.
Evidence Review
No meta-analyses or systematic reviews indexed for this ingredient yet.
Dimensions marked N/A have no indexed evidence of that class. They are shown as unavailable rather than scored.
Practical Use & Dosage
- Minimum Effective Dose
- 200 mg (single dose studied)
- Optimal Range
- 200 mg single dose (evidence limited to this dose in the provided trials)
- Upper / Caution Level
- Not established
- Timing
- In the trials, assessments were conducted ~60 minutes after oral dosing before exercise
- Best Format
- Oral capsule/powder (as used in trials)
- Bioavailability
- Not characterised in the provided abstracts
- Absorption Considerations
- Not characterised in the provided abstracts
Safety & Interactions
Side Effects
- •Not well characterised in the provided trials; no major adverse events reported in these studies
Contraindications
- Not established from the provided abstracts
Drug Interactions
- •Not established from the provided abstracts
Who Should Avoid
- •Not established from the provided abstracts
Monitoring
No specific monitoring recommendations are provided in the supplied trials; safety data remain limited.
Frequently Asked Questions
Auto-generated from indexed evidence — dosage, safety, interactions, and more.
When is Paraxanthine typically used or indicated?
Paraxanthine is most commonly used for: Acute cognitive support, Pre-workout focus/ergogenic adjunct, Alternative to caffeine for those concerned about sleep disruption. Not specified in the supplied trials beyond assessment of acute central nervous system effects and subjective sleep measures following single-dose administration.
How does Paraxanthine work?
Not directly evaluated in the provided abstracts. The ingredient was studied as an orally administered compound for acute cognitive and performance effects, but mechanistic details are not reported in these trials.
What is the recommended dose of Paraxanthine?
The optimal range is 200 mg single dose (evidence limited to this dose in the provided trials). with a minimum effective dose of 200 mg (single dose studied). Best taken: In the trials, assessments were conducted ~60 minutes after oral dosing before exercise. Upper / caution level: Not established.
What are the side effects of Paraxanthine?
Reported side effects include: Not well characterised in the provided trials; no major adverse events reported in these studies. Monitoring: No specific monitoring recommendations are provided in the supplied trials; safety data remain limited.
Does Paraxanthine interact with medications?
Known or theoretical interactions: Not established from the provided abstracts. Always check with a clinician before combining with prescription medication.
Who should avoid Paraxanthine?
Paraxanthine is generally not recommended for: Not established from the provided abstracts; and Not established from the provided abstracts.
How strong is the evidence for Paraxanthine?
Evidence level: Limited (overall score 50/100), based on 2 indexed studies on SuppIndex.
Research & References (2)
Paraxanthine provides greater improvement in cognitive function than caffeine after performing a 10-km run.
Double-blind, randomized, crossover trial in 12 trained runners comparing placebo, caffeine (200 mg), paraxanthine (200 mg), and caffeine+paraxanthine. Cognitive tests were performed before and after a 10-km treadmill run with dosing 60 minutes before testing/exercise.
Comparative effects of caffeine and paraxanthine on rowing performance and sleep quality: a randomized crossover study.
Randomized, double-blind, crossover study in 14 male university rowers comparing four conditions (caffeine+paraxanthine, caffeine alone, paraxanthine alone, placebo), each with 200 mg doses, assessing 2000-m ergometer performance and subjective sleep measures.
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Research Overview
Limited EvidenceCite this ingredient
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Stable URL
https://thesuppindex.com/ingredients/paraxanthine
SuppIndex. (2026). Paraxanthine: Evidence summary, dosage and clinical studies. Retrieved October 16, 2026, from https://thesuppindex.com/ingredients/paraxanthine
Based on 2 indexed studies · Evidence level: Limited.
Goal Ratings
Stack Compatibility
One trial tested paraxanthine combined with caffeine and found the combined condition produced the most pronounced performance benefit versus placebo; interactions and optimal combinations require further study.