Your involvement in this study will be required for 11 weeks, 8 of which you will be required to take the study product. We are recruiting on a rolling basis which means that your individual start date is flexible.

The study design is:

• 4 weeks taking study product
• 3 weeks not taking study product
• 4 weeks taking study product

Please see below for more information. You can also register your interest using the form at the bottom of this page.

Grape seed extract is obtained from the seeds of red wine grapes that are a by-product of the wine industry.

This study is placebo-controlled, and it is also a cross over design. This means that each person in the study will take the active product for a period of 4 weeks, and also take the placebo product for a period of 4 weeks. Neither you nor the investigators will know which order the products will be allocated to you. Upon enrolment, you will be randomly allocated to one of 2 groups.

• Group 1 participants will receive the active product first, then the placebo.
• Group 2 participants will receive the placebo first, then the active.

The product order is allocated randomly on a chance basis, and you will not know which product group you have been allocated to. This is to ensure that no unintentional bias can impact the results.

Placebos are designed to look like the real product being studied except they do not contain the active ingredient. Using a placebo helps us to be confident that any effects we measure in the active group really are due to the active ingredient and not due to the body’s own reaction to a perceived treatment.

Recent studies have shown positive results on high blood pressure and other related circulatory functions after taking grape seed extract. Current drug treatments for circulatory conditions may have side effects for some people so more natural options, like grape seed extract, are being developed and studied.

Your involvement in the study will be for 11 weeks. Many of the study requirements can be completed online at home; however, you will be required to attend our clinic (in Fortitude Valley, Brisbane) 4 times during the study.

During the study, you will be asked to:

• Take the study product daily for a period of 8 weeks
• Attend our clinic 4 times for blood pressure check and blood test, at the same points you will also have a non-invasive scan of your leg to check your blood flow.
• Complete a series of short questionnaires at several points throughout the study.

The information we collect during the study will enable the investigators to assess the product’s effectiveness in improving blood pressure.

To make the timings of these visits as convenient as possible for you, we are recruiting on a rolling basis. This means that your individual start date is flexible. The RDC Clinic is open 6 days a week (from 6.30am).

Please note: This page is a summary of the study outline and participant requirements. A full Participant Information Sheet with detailed information will be provided to you before you are asked to give your consent to participate.

You will be eligible for a $250 reimbursement for your time and travel expenses once all study requirements have been met. Pro rata payments are also available in the case of early withdrawal or for your time in attending the in clinic blood pressure screening.

Payment will be made via direct deposit to your nominated bank account, or you can choose to receive gift cards to the same value. Payment will be issued once, at the conclusion of your involvement in the study.

• Week 1 Full Clinic appointment: $55 (or $30 for blood pressure screen only)
• Week 4 Clinic appointment: $55
• Week 8 Clinic appointment: $55
• Week 11 Clinic appointment: $85

If you are interested in participating, we’d love to hear from you. Please register your interest by answering the questionnaire and completing the form on this page…we’ll then get in touch to screen you for eligibility.

Our clinic is centrally located on Level 3, 252 St Pauls Terrace, Spring Hill. 

We offer free undercover parking directly next door under the Kennigo Hotel, 22 Kennigo Street, Spring Hill.

Getting to Us

• Private Transport: free undercover parking available at Kennigo Hotel Car Park as well as metered street parking (availability for street parking is day/time dependent). Please enter 22 Kennigo Street, Spring Hill into your GPS.
• Train: Fortitude Valley Train Station (350m away)
• Bus: multiple bus stops within close proximity

• Adults over 25 years
• Generally healthy with no uncontrolled or serious illnesses
• BMI 18 – 35kg/m2 (you can check this on the BMI calculator below)
• Have prehypertensive blood pressure (systolic 120-139 mmHg and/or diastolic 80-89 mmHg) – we will confirm this for you at our clinic
• Agree to not change current diet and/or exercise frequency or intensity during entire study period
• Able to provide informed consent
• Able to commit to completing the study requirements

Please register your interest by answering the registration questionnaire and completing the form on this page, we’ll then get in touch to screen you for suitability.

Body Mass Index (BMI) Calculator

Please note: This page is a summary of the study outline and participant requirements. A full Participant Information Sheet with more detailed information will be provided to you before you are asked to give your consent to participate.

This RDC Clinical study has been approved by the Bellberry Human Research Ethics Committee under Approval Number: 2024-01-133. The study is also registered on the clinicaltrials.gov under Registration Number: NCT06440252.

Trained trial coordinators will supervise your progress throughout the study. Your results will be made available to you at the conclusion of the study. Any of your personal information collected during the study will be kept in the strictest confidence.