Caffeine plus paraxanthine modestly improved rowing

May 11, 2026

Caffeine is a familiar performance tool for endurance athletes, but it can also make sleep go a bit feral. This study asked whether paraxanthine, caffeine’s main metabolite, might offer useful performance or sleep-related clues for athletes and coaches.

Reference: Bingol Diedhiou et al. Comparative effects of caffeine and paraxanthine on rowing performance and sleep quality: a randomized crossover study. Journal of the International Society of Sports Nutrition (2026) DOI: 10.1080/15502783.2026.2650339

Study snapshot

A quick, practical summary for runners and coaches.

Quick answer

The researchers tested caffeine, paraxanthine, both together, and placeboA dummy treatment that looks like the real one but has no active ingredient, or no active effect for the outcome being studied, and is used for fair comparison. in male university-level rowers. The combined caffeine-plus-paraxanthine condition produced a small improvement in 2000-m rowing performance, but paraxanthine alone did not clearly improve performance.

The main caution is that this was a small rowing study, not a running study. So, for marathon runners, trail runners, ultra runners, and coaches, the findings are interesting — not practice-changing.

Key takeaways

Caffeine plus paraxanthine modestly improved 2000-m rowing performance versus placebo.
The study was small, male-only, short-term, and used rowing rather than running.
Paraxanthine may be more interesting for athletes worried about caffeine-related sleep disruption than as a proven performance booster.

How confident should we be?

Evidence confidence: Low

The randomized crossover design was useful, and the performance test was meaningful for rowers. But the sample was tiny, male-only, rowing-specific, and the sleep outcomes were subjective.

Bottom line

The study suggests that caffeine plus paraxanthine may modestly improve short, hard rowing performance, but paraxanthine alone did not clearly work as a performance enhancer. For runners, the evidence is indirect. Caffeine remains the better-supported option, while paraxanthine is worth watching for athletes who train late or struggle with caffeine-related sleep problems.

FAQ

Does paraxanthine improve running performance?

Not based on this study. The study tested rowing, not running, and paraxanthine alone did not clearly improve performance.

Is paraxanthine better than caffeine for endurance athletes?

Not for performance yet. Caffeine has much stronger evidence, while paraxanthine may be more interesting for athletes who are sensitive to caffeine or worried about sleep.

Should runners take caffeine before evening training?

Maybe, but be careful. Caffeine can help performance, but late-day caffeine may worsen sleep, which can undermine recovery.

Did caffeine plus paraxanthine improve performance?

Yes, in this small rowing study. The combined condition modestly improved 2000-m rowing time and mean power compared with placebo.

Is paraxanthine safer for sleep than caffeine?

This study suggests paraxanthine alone may be more favourable for subjective sleep than caffeine-containing conditions. But the study did not use objective sleep tracking, so the evidence remains limited.

Related Veohtu articles

Thanks for reading! If you enjoy these nerd alerts, please help me out!

⭐ Leave a 5-star review

Follow @veohtu on social media:

Reviews and follows train the magical algorithms to promote my content higher up the rankings so that more folks see high-quality information.

This content is free.
Please help keep it alive by buying me a beer.

Share this nerd alert with your people:

Disclaimer I occasionally mention brands and products, but it is important to know that I don't sell recovery products, supplements, or ad space, and I'm not affiliated with / sponsored by / an ambassador for / receiving advertisement royalties from any brands. I have conducted biomedical research for which I’ve received research money from publicly funded national research councils and medical charities and also from private companies, including the Novo Nordisk Foundation, AstraZeneca, Amylin, the A.P. Møller Foundation, and the Augustinus Foundation. I’ve also consulted for Boost Treadmills and Gu Energy on R&D grant applications, and I provide research and scientific writing services for Examine.com. Some of my articles contain links to information provided by Examine.com, but I do not receive any royalties or bonuses from those links. Importantly, none of the companies described above have had any control over the research design, data analysis, or publication outcomes of my work. I research and write my content using state-of-the-art, consensus, peer-reviewed, and published scientific evidence combined with my empirical evidence observed in practice and feedback from athletes. My advice is, and always will be, based on my own views and opinions shaped by the scientific evidence available. The information I provide is not medical advice. Before making any changes to your habits of daily living based on any information I provide, always ensure it is safe for you to do so and consult your doctor if you are unsure.