Evidence map›Paper›PMID 40506665›Full record

Trial reportEuropean journal of applied physiology2025

The effects of acute and chronic oral tea catechins and ornithine supplementation on exercise-induced ammonia accumulation and cycling performance in healthy young men: a randomized, double-blind, cross-over, placebo-controlled trial.

Chihiro Nagayama, Yuka Hamada, Kayoko Kamemoto, Takahiro Hasumura, Yoshihiko Minegishi, Yuji Matsui, Noriyasu Ota, Masashi Miyashita

Abstract readRandomized Controlled Trial
In one paragraph

Trial report in European journal of applied physiology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Chihiro NagayamaGraduate School of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan.ORCID http://orcid.org/0000-0002-2098-3484
Yuka HamadaInstitute for Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan.ORCID http://orcid.org/0000-0001-9855-1414
Kayoko KamemotoInstitute for Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan.ORCID http://orcid.org/0000-0001-9231-2375
Takahiro HasumuraBiological Science Research, Kao Corporation, Ichikai-Machi, Tochigi, Japan.ORCID http://orcid.org/0000-0001-5229-8775
Yoshihiko MinegishiBiological Science Research, Kao Corporation, Ichikai-Machi, Tochigi, Japan.ORCID http://orcid.org/0009-0000-3215-3528
Yuji MatsuiHealth & Wellness Products Research Laboratories, Kao Corporation, Sumida, Tokyo, Japan.ORCID http://orcid.org/0000-0001-5524-7009
Noriyasu OtaBiological Science Research, Kao Corporation, Ichikai-Machi, Tochigi, Japan.ORCID http://orcid.org/0000-0003-0428-7160
Masashi MiyashitaFaculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan. m.miyashita@waseda.jp.ORCID http://orcid.org/0000-0002-7656-641X

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeThis study examined the effects of acute and chronic oral intake of tea catechins and ornithine supplementation on exercise-induced ammonia accumulation and cycling performance.

methodsSixteen healthy young men participated in a randomized, double-blind, cross-over, placebo-controlled study. For the acute trials, the participants consumed either tea catechins and ornithine (CO) or placebo (P) and performed cycling exercises at an intensity corresponding to 75% of the maximum heart rate for 60 min, followed by a 15-min cycling performance test. The participants continued to consume each designated supplement for 13 days. For the chronic trials, the participants repeated the same protocol as the acute trials on day 14. After a washout period, the participants changed the supplement and repeated the same protocol as above.

resultsPlasma catechins (acute ES = 3.61; chronic ES = 2.64, p < 0.001) and ornithine (acute ES = 4.28; chronic ES = 2.25, p < 0.001) concentrations were higher in both acute and chronic CO trials than those in P trials. No differences were found in plasma ammonia concentration measured during the whole experimental period and in mean power output during the performance test among trials. Subjective fatigue during 60-min cycling was lower in both acute and chronic CO trials than those in P trials (acute ES = 0.32, chronic ES = 0.60, p < 0.001).

conclusionsA single dose and 14-day oral intake of tea catechins and ornithine supplementation did not suppress exercise-induced ammonia accumulation or enhance cycling performance. CLINICAL TRIAL: Clinical trial registration ID: UMIN000035267.

Indexed as

AmmoniaAthletic PerformanceBicyclingCatechinExerciseOrnithineTeaAdministration, OralAdultCross-Over StudiesDietary SupplementsDouble-Blind MethodHumansMaleYoung AdultAmmoniaCatechinOrnithineTeaAmmonia metabolismExercise performanceOrnithineSupplementationTea catechins

Identifiers

PMID40506665
PMCPMC12528257

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.