Effects of L-Citrulline or Citrulline-malate on Neuromuscular Performance in Resistance-trained Adults

Malate or Not?: Effects of L-Citrulline or Citrulline-malate on Neuromuscular Performance in Resistance-trained Adults

The main aim of this study is to compare the effects of L-Citrulline vs. Citrulline-malate on neuromuscular performance (maximal dynamic strength and maximal endurance strength) in resistance-trained adults.

Study Overview

• Status: Completed
• Conditions: Neuromuscular Performance
• Intervention / Treatment: Dietary supplement: L-citrulline; Dietary supplement: Citrulline-malate; Dietary supplement: Placebo

Detailed Description

Nitric oxide (NO) is a ubiquitous gaseous molecule that plays a critical role in the regulation of cardiovascular function and in the signaling of multiple cellular processes. Specifically, NO could reduce the oxygen cost of exercise and adenosine triphosphate (ATP) in the production of muscle contractile force, improving calcium handling, glucose uptake and mitochondrial efficiency in muscle fibers. Therefore, it has been suggested that increasing the availability of NO through the oral intake of food and nutritional supplements may be useful to delay the onset of fatigue and improve performance in high-intensity efforts.

L-citrulline is a nonessential amino acid involved in the urea cycle that acts as an endogenous precursor of L-arginine, being a more efficient alternative to L-arginine to increase the plasma concentration of L-arginine through the nitric oxide synthase (NOS) pathway.

On the other hand, citrulline malate is an organic salt of L-citrulline and malate which has been shown to exert a small but significant ergogenic effect in different high-intensity efforts compared to a placebo. However, no study to date has compared L-citrulline VS. citrulline malate to assess whether there is an additive effect from malate to exercise performance.

50 resistance-trained adults (50% women) will be randomized into three conditions (L-citrulline, citrulline-malate and placebo conditions) with 48 hours of separation between conditions. 48h previous to the randomization the participants will perform a familiarization to avoid the learning effects.

Each evaluation day will conform to the following tests:

• Maximal dynamic strength of lower- and upper-body
• Maximal endurance strength of lower- and upper-body

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Granada, Spain, 18011
    • Jonatan Ruiz Ruiz

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy male or female
• Ages 18-30years
• BMI: 18-30.0 kg/m2
• Stable weight over the last 3 months (body weight changes<3kg)
• Previous experience in resistance training (i.e., at least 1 year with a frequency of two or more training sessions per week),
• Participant must be capable and willing to provide consent, understand exclusion criteria, instructions and protocols.

Exclusion Criteria:

• History of chronic diseases (renal disease, diabetes, cardiovascular disease, cancer, VIH, hepatic disease, food disorders)
• Pregnant, planning to become pregnant, or breastfeeding
• Have been treated previously or during the study period with prescription drugs:

antihypertensive, lipid lowering, acid uric lowering, glucose lowering, beta blockers or any drug that under the investigator's judged could influence the results.

• Allergy/intolerance to any ingredient of the dietary supplements.
• Chronic consumers of dietary NO-precursors dietary supplements (citrulline malate, arginine, nitrates).
• Any non-controlled medical condition which could influence results or could be worsened by the participation in the study.
• Are deemed unsuitable by the investigator for any other reason, that prevent data collection.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental: L-Citrulline; 5 g of L-citruline + 5 g of additives. The dose to be administered is that recommended on the labeling and nutritional information of the product, which has been produced under GMP procedures and approved by the EFSA (Lifepro®).	Dietary supplement: L-citrulline; 5 g of L-citruline + 5 g of additives
Experimental: Experimental: Citrulline-malate; 8g of citrulline-malate + 2 g of additives. The dose to be administered is that recommended on the labeling and nutritional information of the products which has been produced under GMP procedures and approved by the EFSA (Lifepro®).	Dietary supplement: Citrulline-malate; 8g of citrulline-malate + 2 g of additives
Placebo Comparator: Placebo; 10g of maltodextrin plus additives (Lifepro®).	Dietary supplement: Placebo; 10g of maltodextrine

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal endurance strength	Maximal endurance strength of lower- and upper-body (squat and bench press exercises)	1 hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal dynamic strength	Maximal dynamic strength of lower- and upper-body (squat and bench press exercises)	1 hour

Collaborators and Investigators

• Sponsor: Universidad de Granada

Study record dates

Study Major Dates

• Study Start (Actual): February 15, 2022
• Primary Completion (Actual): June 30, 2022
• Study Completion (Actual): June 30, 2022

Study Registration Dates

• First Submitted: December 21, 2021
• First Submitted That Met QC Criteria: December 21, 2021
• First Posted (Actual): January 11, 2022

Study Record Updates

• Last Update Posted (Actual): November 4, 2022
• Last Update Submitted That Met QC Criteria: November 3, 2022
• Last Verified: November 1, 2022

More Information

Terms related to this study

• Keywords: dietary supplement; nitric oxide; resistance training; citrulline malate
• Other Study ID Numbers: Malate or Not Project

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No