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NCT Number: NCT05251207

Plasma Trimethylamine N-oxide Elevation Induced by L-carnitine Supplementation and Insulin Resistance

The primary aims of the current study:

* using L-carnitine supplementation modulate the level of plasma trimethylamine N-oxide to assess its effect on circulating cytokines related to diabetes and metabolic syndrome; * using simulated night-shift work intervention as a stress factor, explore the effect of circulating metabolites on insulin sensitivity

The secondary aim is to evaluate the effect of carnitine supplementation on gut microbiome composition.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Insulin Resistance Glucose Metabolism Disorders Hyperinsulinism Metabolic Diseases Nutritional and Metabolic Diseases

Age range

20 year–30 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Akademia Wychowania Fizycznego

Poznan, 61-871, Poland

About this study

Subjects will be randomly divided in two groups: supplemented by L-carnitine 2g/day for 12 weeks, and placebo group receiving leucine in identical gelatine capsules.

Subjects who successfully complete the protocol will be divided into four subgroups - two with a changed circadian cycle and two controls (supplemented and placebo). Subgroups with a changed daily cycle will be able to sleep between 8:00 and 17:00 for four consecutive days, while during the night they will stay active in the laboratory. The oral glucose tolerance test (OGTT) will be performed before and after the circadian cycle modification. Glucose levels will be monitored by FreeStyle Libre Sensor. Moreover, the activity of the participants will be monitored by wearable activity trackers.

Before supplementation, as well as before circadian cycle modification and after finishing the whole experimental procedure, fasting blood samples will be collected for determination of plasma trimethylamine N-oxide (TMAO), trimethylamine (TMA), carnitine (free and acyl derivatives), protein markers of diabetes and inflammation.

Moreover, the stool samples will be collected before and after 12 weeks of supplementation, to determine the composition of the gut microbiome. In addition diet of participants will be monitored.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • healthy volunteers,
  • must be able to swallow tablets

Exclusion criteria

  • smokers,
  • cardiovascular disease
  • liver disease
  • kidney disease
  • gastrointestinal disorders (including stomach ulcers and erosions)
  • diabetes

Treatment and study plan

L-carnitine

Dietary Supplement

L-carnitine-L-tartrate

L-leucine

Dietary Supplement

L-leucine

Change of the circadian cycle

Behavioral

Reducing sleep at night for four consecutive days (enabling sleep between 8:00 and 17:00)

Primary outcomes

  1. Circulating microbiome metabolites

    Time frame: 13 weeks

    Determination of plasma trimethylamine and trimethylamine N-oxide using ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) method

  2. Circulating carnitine metabolites

    Time frame: 13 weeks

    Determination of plasma free, total, and acyl-L-carnitines using ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) method

  3. Circulating diabetes biomarkers

    Time frame: 13 weeks

    insulin, C-peptide, ghrelin, leptin, resistin using enzyme-linked immunosorbent assay

  4. Circulating inflammatory biomarkers

    Time frame: 13 weeks

    tumor necrosis factor, C-reactive protein using enzyme-linked immunosorbent assay

  5. Oral Glucose Tolerance Test

    Time frame: 1 week

    The subjects will consume 75 g of glucose solution drink within a 5-minute time frame. The glucose level will be continuously monitored with the FreeStyle Libre Sensor.

Secondary outcomes

  1. gut microbiome composition

    Time frame: 13 weeks

    16 S rRNA sequencing will be used to analyze the gut microbiome in the stool samples

Sponsors and collaborators

Lead sponsor

Poznan University of Physical Education

Other

Registry information

Official study title

The Role of Gut Microbiota Metabolite, Trimethylamine N-oxide, in the Insulin Resistance Development

Acronym: MR

Important dates

Study start
2022
Primary completion
2026
Study completion
2027
First posted
Feb 22, 2022
Registry last updated
Oct 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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