Effects of L-arginine and L-citrulline Supplementation on Muscle Respiration

Loughborough University

Status: Completed

Conditions: Dietary Exposure

Treatments: Dietary Supplement: Dietary Supplement; Behavioral: Endurance exercise on a cycle ergometer

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT03998800

R19-P010

Details and patient eligibility

About

The objective of this trial is to determine the effects of dietary supplementation with the amino acids, L-arginine and L-citrulline, on endurance performance and mitochondrial respiration in healthy men compared to supplementation with L-arginine alone and a placebo supplement.

Full description

This study is a randomized, double-blind, cross over trial of L-arginine and L-citrulline supplementation, L-arginine supplementation alone and placebo supplementation in healthy men. The intervention period will be 8-11 weeks for each participant and a minimum of 15 individuals will be recruited and enrolled to complete the trial. Subjects will complete the experimental protocol described below over 3 individual 10 day supplementation periods, separated by washout periods of approximately 2 weeks. Subjects will ingest corn-starch as a placebo, L-arginine (3g/day) or L-arginine (1.5 g/day) + L-citrulline (1.5g/day). On day 7 of the supplementation period, a skeletal muscle biopsy and blood sample will be obtained from the subjects to investigate mitochondrial function and blood amino acid and nitric oxide levels. On day 10 of the supplementation period, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance. These assessments will be performed to determine the effects of co-ingesting L-arginine and L-citrulline compared to L-arginine alone and placebo administration.

Enrollment: 18 patients

Sex: Male

Ages: 18 to 40 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• healthy male, 18-40 years of age
• recreationally-active
• healthy BMI (≥18.5 and ≤24.9 kg/m2)

Exclusion criteria

• participating in other studies currently or in the past two months or has an intention to participate in other studies over the period of this study
• history of gastric, digestive, cardiovascular, renal disease or any other orthopaedic diseases related to motor organs
• lidocaine allergy
• use of medication that may affect study measures
• contraindication to the biopsy procedures
• on medications that affect the immune system
• on Aspirin or other drugs known to prolong bleeding
• smoker
• user of dietary supplements currently or in the past one month
• a heavy drinker

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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18 participants in 3 patient groups, including a placebo group

L-arginine and L-citrulline

Experimental group

Description:

10 days of supplementation with 1.5 g of L-arginine and 1.5 g of L-citrulline per day

Treatment:

Behavioral: Endurance exercise on a cycle ergometer

Dietary Supplement: Dietary Supplement

L-arginine

Experimental group

Description:

10 days of supplementation with 3 g of L-arginine per day

Treatment:

Behavioral: Endurance exercise on a cycle ergometer

Dietary Supplement: Dietary Supplement

Placebo (corn-starch)

Placebo Comparator group

Description:

10 days of supplementation with corn-starch

Treatment:

Behavioral: Endurance exercise on a cycle ergometer

Dietary Supplement: Dietary Supplement