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

What Was Tested

The trial (not phased) is built around L-Carnitine for insulin resistance, prediabetes & type 2 diabetes.

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.

It had four arms (groups): carnitine (experimental), leucine (placebo comparator), modified circadian cycle (experimental) and normal circadian cycle (active comparator).

No sleep at night for four consecutive days (enabling sleep between 8:00 and 17:00).

The registry classes the interventions as behavioral and dietary supplement.

More on the Plan

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.

Who Took Part

Enrollment: 40 actual participants took part.

It was open to people of any sex aged from 20 years up to 30 years.

Healthy volunteers could join, not only people with the condition.

Examples of who could join: Must be able to swallow tablets.

The full record lists 2 inclusion and 6 exclusion criteria; among the exclusions: cardiovascular disease; liver disease; kidney disease.

How the Study Was Run

Design: randomized, parallel-group and double-blind.

The insulin resistance, prediabetes & type 2 diabetes participants were allocated by chance, so the L-Carnitine group and the comparison group should start out alike.

Groups ran in parallel: each of the insulin resistance, prediabetes & type 2 diabetes participants stayed in one arm throughout.

As a double-blind L-Carnitine study, the assignments were hidden from both participants and investigators until the end.

Those kept unaware of assignments: participant and investigator.

It started in 2022-02-07 with completion listed for 2026-05-31.

It ran at 1 site in Poland.

Its stated primary purpose is prevention.

What Was Measured

Primary outcome: Circulating microbiome metabolites (time frame: 13 weeks). Circulating carnitine metabolites (time frame: 13 weeks). Circulating diabetes biomarkers (time frame: 13 weeks).

It also tracked 1 secondary outcome, for example gut microbiome composition.

What This Means in Plain Language

Put simply, this is a not phased, randomized trial of L-Carnitine in 40 people with insulin resistance, prediabetes & type 2 diabetes.

The trial is marked completed; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the L-Carnitine compound page, Insulin resistance, prediabetes & type 2 diabetes research.