Effects of Carnitine Supplementation on Exercise-Induced Muscle Damage: A Randomized Controlled Trial

Summary

This clinical study aims to investigate the effects of L-carnitine supplementation on recovery following high-intensity interval exercise in young athletes. L-carnitine plays an important role in energy metabolism by facilitating the transport of long-chain fatty acids into the mitochondria for oxidation. It has been suggested that L-carnitine supplementation may contribute to improved exercise performance and recovery by reducing metabolic stress and muscle damage associated with high-intensity exercise.

The primary objective of this study is to determine whether L-carnitine supplementation can attenuate exercise-induced muscle damage and delayed onset muscle soreness (DOMS) following high-intensity exercise. In addition, the study aims to evaluate the potential effects of L-carnitine on peak blood lactate concentration, as well as performance-related parameters including maximal power output, relative maximal power output, mean power output, and relative mean power output during high-intensity exercise.

To address these objectives, participants will be randomly assigned to receive either L-carnitine supplementation or a placebo for a period of 21 days. The placebo will consist of an inert substance designed to resemble the supplement but without any active ingredient. The effects of supplementation on performance and recovery outcomes will be evaluated following a standardized high-intensity exercise protocol.

Participants will be instructed to take the assigned supplement daily throughout the supplementation period. Communication and compliance monitoring will be conducted through a WhatsApp group established by the research team, which will be used to provide reminders and ensure adherence to the study protocol.

To minimize potential confounding factors related to pre-existing muscle damage, participants will be instructed to avoid unfamiliar or strenuous physical activity, particularly resistance exercises involving eccentric contractions, for one week prior to the experimental protocol. Additionally, during the supplementation period, participants will be asked to refrain from consuming foods rich in carnitine, such as meat and dairy products, in order to control dietary carnitine intake.

The findings of this study are expected to provide further insight into the potential role of L-carnitine supplementation in enhancing exercise performance and promoting recovery following high-intensity exercise in young athletes.

Conditions

• Recovery Methods
• Exercise and Recovery
• Exercise Fatigue
• Carnitine Ingestion
• Exercise Ergogenics

Interventions

DIETARY_SUPPLEMENT

L-Carnitine

Although the optimal dose and method of L-Carnitine use are not clearly defined in the literature, it has been reported that daily doses of 2-4 g are relatively ineffective in raising plasma levels unless used due to bioavailability. On the other hand, it has been suggested that the absolute bioavailability of oral doses greater than 1 g is less than 20% due to low gastrointestinal membrane permeability and limited capacity of intestinal transporters. However, pharmacokinetic data support the administration of L-Carnitine in several doses per day. Therefore, while the literature shows varying doses ranging from 1-4 g/day, generally in single daily doses, in this study, L-Carnitine participants will be given 3 g (3 g/d) of L-Carnitine daily for 3 weeks, at 1 g (1 g/8h) every 8 hours.

OTHER

Placebo

In this study, placebo group participants will be given 3 grams (3g/d) of powdered sugar daily (1g/8h) at 8-hour intervals for 3 weeks, which resembles L-Carnitine supplements in shape and color.

Sponsors & Collaborators

• T.C. Dumlupınar Üniversitesi

  collaborator OTHER

• Istanbul Sabahattin Zaim University

  lead OTHER

Principal Investigators

• Halit HARMANCI, Professor Doctor · Republic of Turkey KUtahya Dumlupınar University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

25 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-05-09

Primary Completion

2025-05-15

Completion

2025-06-05

Countries

• Turkey (Türkiye)

Study Locations