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Completed

NCT Number: NCT05143879

Long-Term Effect of Combined Citrulline and Nitrate-Rich Beetroot Extract Supplementation

Citrulline (CIT) and nitrate-rich beetroot extract (BEET) are widely studied ergogenic aids. However, both supplements have been studied in sort-term and isolated. To the best of the authors' knowledge, the effects of combining both supplements on exercise-induced muscle damage (EIMD) and hormone status have not been investigated to date. Therefore, the main purpose of this study was to determine the effect and degree of potentiation of the long-term (9 weeks) mixture of 3 g/day of CIT plus 2.1 g/day of BEET (300 mg/day of NIT) supplementation on EIMD markers (urea, creatinine, AST, ALT, GGT, LDH and CK) and anabolic/catabolic hormone status (testosterone, cortisol and Testosterone cortisol ratio (T/C)) in male trained triathletes. This study was a double-blind, placebo-controlled trial where participants (n = 32) were randomized into 4 different groups: placebo group (PLG; n = 8), CIT group (CITG; 3 g/day of CIT; n = 8), BEET group (BEETG; 2.1 g/day of BEET (300 mg/day of NIT) ; n = 8) and CIT-NIT group (CIT-BEETG; 3 g/day of CIT plus 2.1 g/day of BEET (300 mg/day of NIT); n = 8). Blood samples were collected from all participants at baseline (T1) and after 9 weeks of supplementation (T2).

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Key information

Conditions

Citrulline Athletes Nitrate

Age range

25 year–35 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

University of Leon

León, Castille and León, 24004, Spain

About this study

Triathlon is an endurance sport in which athletes compete sequentially in swimming, cycling and running. Prolonged and strenuous training combined with insufficient recovery can produce muscular and metabolic stress, resulting in structural and functional damage to the musculoskeletal system leading to a fatigue status, which results in decreased athletic performance. As a consequence of this type of combined exercise, there are also alterations in biochemical markers of exercise-induced muscle damage (EIMD) as well as anabolic/catabolic hormones. Therefore, their analysis is useful in determining the balance between training loads and recovery. In this sense, it is essential to include different strategies to reduce or prevent EIMD, which delay or reduce muscle fatigue and improve sports performance. One of these strategies is the use of different ergogenic aids such as L-citrulline (CIT) and nitrates (NIT) which have been proposed as both substances produce an increase in nitric oxide (NO).

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Males between 25 and 35 years old
  • Triathletes
  • With at least 5 years of experience
  • Without any disease
  • Non smokers
  • Non drinkers of alcohol
  • Not to take any other medications or stimulant substances during the study
  • 2 weeks without taking other nutritional supplements

Exclusion criteria

  • Exclusion criteria:
  • Men under 25 and over 35 years of age.
  • Non triathletes
  • Less than 5 years of experience
  • With any disease
  • Smokers
  • Alcohol drinkers

Treatment and study plan

Citrulline

Dietary Supplement

3 g/day during 9 weeks

Nitrate

Dietary Supplement

300 mg/day during 9 weeks

Nitrate plus Citrulline

Dietary Supplement

3 g/day of citrulline and 300 mg/day of nitrate during 9 weeks

Placebo

Dietary Supplement

3 g/day during 9 weeks

Other names: Cellulose

Primary outcomes

  1. Cortisol

    Time frame: 9 weeks

    μg/dL

  2. Testosterone

    Time frame: 9 weeks

    ng/mL

  3. Testosterone to cortisol ratio

    Time frame: 9 weeks

    ng/mL

  4. Urea

    Time frame: 9 weeks

    mg/dl

  5. Creatinine

    Time frame: 9 weeks

    mg/dl

  6. AST

    Time frame: 9 weeks

    U/L

  7. ALT

    Time frame: 9 weeks

    U/L

  8. GGT

    Time frame: 9 weeks

    U/L

  9. LDH

    Time frame: 9 weeks

    U/L

  10. CK

    Time frame: 9 weeks

    U/L

Sponsors and collaborators

Lead sponsor

Burgos Nutrition

Other

Collaborators

  • Universidad de León
  • University of Valladolid
  • University of the Basque Country (UPV/EHU)

Registry information

Official study title

Long-term Effect of Combined Citrulline and Nitrate-rich Beetroot Extract Supplementation on Recovery Status in Trained Male Triathletes

Important dates

Study start
2018
Primary completion
2018
Study completion
2021
First posted
Dec 3, 2021
Registry last updated
Dec 3, 2021

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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