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Completed

NCT Number: NCT06440252

Effectiveness of a Grape Seed Extract on Circulatory Measures in Healthy Adults

This is a randomized, double-blind, placebo-controlled, 2 arm crossover study conducted over 11 weeks, with participants randomised to a product for 4 weeks, followed by a 3-week washout period before completing the second product for 4 weeks, to study the effectiveness of a grape seed extract on circulatory measures in healthy adults.

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Key information

Conditions

Circulatory; Change

Age range

25 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

RDC Clinical Pty Ltd

Brisbane, Queensland, 4006, Australia

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Adults 25 years or older
  • Generally healthy
  • BMI 18 - 35kg/m2
  • Able to provide informed consent
  • Have prehypertensive blood pressure (systolic 120-139 mmHg and/or diastolic 80-89 mmHg)
  • Agree to not change current diet and/or exercise frequency or intensity during entire study period
  • Agree to not participate in another clinical trial while enrolled in this trial

Exclusion criteria

  • Those with a history of myocardial infarction, angina or bleeding disorders
  • Those who have uncontrolled thyroid diseases
  • Currently taking dietary supplements for circulation (e.g. fatty acids, CoQ10, L-arginine, red ginseng, ginseng, natto, ginkgo) or use of these in the last 1 month
  • Currently taking inflammation or circulatory associated medications (e.g. Pentoxifylline and vasodilators like nitroglycerin) or use of these in the last 1 month
  • Currently taking statins medication including atorvastatin (e.g. Lipitor, Lorstat), fluvastatin (e.g. Lescol or Vastin), pravastatin (e.g. Pravachol, Cholstat), rosuvastatin (e.g. Cavstat, Crestor) or simvastatin (e,g, Lipex, Zocor, Zimstat).
  • Currently taking Coumadin, Marevan (Warfarin), Heparin, Dalteparin, Enoxaparin or other anticoagulation therapy, or substrates of P-glycoprotein including (but not limited to) calcium channel blockers, cyclosporin, digoxin, erythromycin and protease inhibitors(1).
  • Have a serious illness(2) e.g. mood disorders such as bipolar disorder, neurological disorders such as MS, kidney disease, liver disease or heart conditions
  • Have an unstable illness(3) (i.e., changing medication/treatment)
  • Malignancy or treatment for malignancy within the previous 2 years (this excludes non-melanoma (e.g. BCC and SCC) skin cancers not requiring radiation or chemotherapy)
  • Active smokers, nicotine use or drug (prescription or illegal substances) abuse
  • Chronic past and/or current alcohol use (>14 alcoholic drinks week)
  • Allergic to any of the ingredients in active or placebo formula
  • Pregnant or lactating woman or women trying to conceive
  • Any condition which in the opinion of the investigator makes the participant unsuitable for inclusion
  • Participated in another trial in the past 1 month
  • Any participant that begins taking antiplatelet medication during the trial will be excluded from the study
  • A serious illness is a condition that carries a risk of mortality, negatively impacts quality of life and daily function and/or is burdensome in symptoms and/or treatments.
  • An unstable illness is any illness that is currently not being treated with a stable dose of medication or is fluctuating in severity.

Treatment and study plan

Grape Seed Extract

Drug

One daily dose of 1 capsule containing 600mg grape seed extract

Maltodextrin

Drug

One daily dose of 1 capsule

Primary outcomes

  1. Change in Diastolic blood pressure (arm)

    Time frame: Baseline, week 4, week 8, week 11

    Change in Diastolic blood pressure (arm) as measured by blood pressure machine

Secondary outcomes

  1. Change in Systolic blood pressure (arm)

    Time frame: Baseline, week 4, week 8, week 11

    Change in Systolic blood pressure (arm) as measured by blood pressure machine

  2. Change in Peripheral systolic and diastolic blood pressure (leg)

    Time frame: Baseline, week 4, week 8, week 11

    Change in Peripheral systolic and diastolic blood pressure (leg) as measured by blood pressure machine

  3. Change in HGB

    Time frame: Baseline, week 4, week 8, week 11

    Change in HGB as measured by FBC via blood test

  4. Change in WBC

    Time frame: Baseline, week 4, week 8, week 11

    Change in WBC as measured by FBC via blood test

  5. Change in RBC

    Time frame: Baseline, week 4, week 8, week 11

    Change in RBC as measured by FBC via blood test

  6. Change in Platelet Aggregation

    Time frame: Baseline, week 4, week 8, week 11

    Change in Platelet Aggregation as measured by FBC via blood test

  7. Change in (endothelial nitric oxide synthase) eNOS

    Time frame: Baseline, week 4, week 8, week 11

    Change in eNOS as measured via blood test

  8. Change in endogenous nitric oxide (NO)

    Time frame: Baseline, week 4, week 8, week 11

    Change in NO as measured via blood test

  9. Change in Tibial artery structure

    Time frame: Baseline, week 4, week 8, week 11

    Change in Tibial artery structure via Laser Doppler Flowmetry

  10. Change in blood flow of the right leg

    Time frame: Baseline, week 4, week 8, week 11

    Change in blood flow of the right leg via Laser Doppler Flowmetry

  11. Change in oxygen saturation

    Time frame: Baseline, week 4, week 8, week 11

    Change in oxygen saturation as measured by pulse oximeter

  12. Change in resting pulse rate

    Time frame: Baseline, week 4, week 8, week 11

    Change in resting pulse rate as digital blood pressure and resting pulse rate machine

  13. Change in weight

    Time frame: Baseline, week 4, week 8, week 11

    Change in weight as measure by digital scales

  14. Change in Body Mass Index (BMI)

    Time frame: Baseline, week 4, week 8, week 11

    Change in BMI as measured by weight and height calculation

  15. Change in waist and hip circumference

    Time frame: Baseline, week 4, week 8, week 11

    Change in waist and hip circumference as measured by tape measure

  16. Change in 36-Item Short Form Health Survey (SF-36)

    Time frame: Baseline, week 4, week 8, week 11

    Change in 36-Item Short Form Health Survey (SF-36) as self-reported

  17. Change in E/LFT

    Time frame: Baseline, week 4, week 8, week 11

    Change in E/LFT as measured via blood test

  18. Change in triglycerides

    Time frame: Baseline, week 4, week 8, week 11

    Change in triglycerides as measured via blood test

  19. Change in cholesterol

    Time frame: Baseline, week 4, week 8, week 11

    Change in cholesterol as measured via blood test

  20. Change in blood glucose

    Time frame: Baseline, week 4, week 8, week 11

    Change in blood glucose as measured via blood test

  21. Change in adverse events

    Time frame: Baseline, week 4, week 8, week 11

    Change in adverse events as reported by participant

Sponsors and collaborators

Lead sponsor

RDC Clinical Pty Ltd

Industry

Registry information

Official study title

The Effectiveness of a Grape Seed Extract on Circulatory Measures in Healthy Adults: a Randomised, Double-blind, Placebo-controlled Crossover Study

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Jun 3, 2024
Registry last updated
Mar 6, 2026

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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