Home Ingredients FitGrape® (Grape Polyphenol Extract)
AntioxidantCardiovascular

FitGrape® (Grape Polyphenol Extract)

Vitis vinifera
Evidence Level
Preliminary
1 Clinical Trial
4 Documented Benefits
1/5 Evidence Score

FitGrape® is a grape (Vitis vinifera) extract concentrated for polyphenols, including the oligomeric proanthocyanidins (OPCs). No published study has tested FitGrape itself. The one individual trial cited on this page used a different company's grape seed extract, in people with a rare autoimmune disease, and measured blood markers rather than how people felt or any health outcome. The blood pressure figures come from pooled analyses of generic grape seed extract, not FitGrape.

Studied Dose Product labels commonly suggest 100 to 300 mg per day; no published trial has tested FitGrape at any dose.
Active Compound Grape extract concentrated for polyphenols and oligomeric proanthocyanidins (OPCs).

Benefits

Antioxidant defense

The only human study cited here tested Activin, a different company's grape seed proanthocyanidin extract, not FitGrape. It was done in people with systemic sclerosis, a rare autoimmune connective-tissue disease, and it reported lower blood levels of malondialdehyde (an oxidative-stress marker) and of the adhesion molecules ICAM-1, VCAM-1, E-selectin and P-selectin. Those are laboratory markers, not symptoms or health outcomes, and nothing here shows what FitGrape does in a healthy person.

Supported by Trial 1

Blood-vessel effects are unproven

This is a proposed idea, not something the Activin study measured; pooled grape seed extract trials found no significant change in flow-mediated dilation, a test of vessel relaxation. That study looked at adhesion molecules in the blood, which are markers researchers track in vessel biology. It did not measure blood flow, blood pressure or any circulation outcome, and it did not test FitGrape.

Supported by Trial 1

Cell protection (laboratory finding only)

Grape OPCs act as antioxidants in laboratory tests. Whether taking FitGrape protects cells or tissues in people has not been tested.

Supported by Trial 1

Slightly lower diastolic blood pressure in grape seed extract trials

Studied as generic grape seed extract, not FitGrape, and FitGrape's grape source is not stated. A pooled analysis of 19 controlled trials found diastolic pressure 2.2 mmHg and heart rate 1.25 beats per minute lower than controls, but no significant change in systolic pressure or vessel dilation, with very high variation between trials. An earlier pooled analysis of 16 trials (810 people) reported larger drops.

Supported by Trial 1

Mechanism of action

1

Proanthocyanidin antioxidants

Grape OPCs can neutralize free radicals in laboratory tests, and researchers think they may help the body's own antioxidant enzymes. This is the proposed explanation for how they might work. It has not been confirmed for FitGrape in people.

2

Vascular signaling

Grape polyphenols are thought to influence nitric oxide, a signal that helps blood vessels relax. This is a theory drawn from other grape research, not something the Activin study cited on this page measured.

Clinical trials

1
Activin grape seed extract in people with systemic sclerosis (2002)
PubMed

A 2002 study of Activin, a grape seed proanthocyanidin extract made by a different company. It is not a study of FitGrape. It measured blood markers of oxidative stress and adhesion molecules. (Kalin et al. 2002, Free Radical Research)

People with systemic sclerosis (scleroderma), a rare autoimmune connective-tissue disease. Not healthy adults.

The extract lowered blood levels of malondialdehyde (an oxidative-stress marker) and of the adhesion molecules ICAM-1, VCAM-1, E-selectin and P-selectin. These are surrogate laboratory markers. The study did not report symptom or clinical outcomes, and the results belong to Activin, not to FitGrape.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated.
Mild digestive upset is occasionally reported.
Discontinue if any unusual reaction occurs.

Important Drug interactions

Blood thinners and antiplatelet drugs such as warfarin, clopidogrel or daily aspirin: grape seed polyphenols may add to their blood-thinning effect and could increase bruising or bleeding. Talk to your doctor before combining them.
Blood pressure medication — possible additive effect; monitor.
Tell your doctor before surgery.

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Frequently asked questions about FitGrape® (Grape Polyphenol Extract)

What is FitGrape?

FitGrape® is a grape (Vitis vinifera) extract concentrated for polyphenols, including the oligomeric proanthocyanidins (OPCs). No published study has tested FitGrape itself.

What is FitGrape used for?

FitGrape is researched primarily for Antioxidant and Cardiovascular. The only human study cited here tested Activin, a different company's grape seed proanthocyanidin extract, not FitGrape. It was done in people with systemic sclerosis, a rare autoimmune connective-tissue disease, and it reported lower blood…

What is the recommended dosage of FitGrape?

The clinically studied dose is Product labels commonly suggest 100 to 300 mg per day; no published trial has tested FitGrape at any dose. Always follow the product label and check with a healthcare provider for personal advice.

Is FitGrape safe, and does it have side effects?

Side effects and cautions reported for FitGrape include: Generally well-tolerated. Mild digestive upset is occasionally reported. It may also interact with some medications. FitGrape is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does FitGrape interact with any medications?

Possible interactions include: Blood thinners and antiplatelet drugs such as warfarin, clopidogrel or daily aspirin: grape seed polyphenols may add to their blood-thinning effect and could increase bruising or bleeding. Talk to your doctor before combining them. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for FitGrape?

NutraSmarts rates the evidence for FitGrape as Preliminary (1 out of 5). It is backed by 1 study summary and 3 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(3 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Kalin R, Righi A, Del Rosso A, et al. Activin, a grape seed-derived proanthocyanidin extract, reduces plasma levels of oxidative stress and adhesion molecules (ICAM-1, VCAM-1 and E-selectin) in systemic sclerosis. Free Radic Res. 2002;36(8):819-25..PubMedUsed to support: Study of Activin, a different company's grape seed proanthocyanidin extract, in people with systemic sclerosis. It measured blood markers of oxidative stress and adhesion molecules, not clinical outcomes, and it did not test FitGrape.
  2. Foshati S, Nouripour F, Sadeghi E, Amani R. The effect of grape (Vitis vinifera) seed extract supplementation on flow-mediated dilation, blood pressure, and heart rate: A systematic review and meta-analysis of controlled trials with duration- and dose-response analysis. Pharmacol Res. 2022;175:105905..PubMedUsed to support: Systematic review and meta-analysis of 19 controlled trials of generic grape seed extract: diastolic blood pressure 2.20 mmHg (I2 88.8%) and heart rate 1.25 bpm lower; no significant effect on systolic pressure (-3.55 mmHg, I2 97.4%) or flow-mediated dilation. Not a study of FitGrape. Backs the cardiovascular benefit.
  3. Zhang H, Liu S, Li L, Liu S, Liu S, Mi J, Tian G. The impact of grape seed extract treatment on blood pressure changes: A meta-analysis of 16 randomized controlled trials. Medicine (Baltimore). 2016;95(33):e4247..PubMedUsed to support: Meta-analysis of 16 randomized trials (810 subjects) of generic grape seed extract: systolic -6.08 mmHg and diastolic -2.80 mmHg, larger in younger, obese and metabolic syndrome subgroups; authors call for larger trials given the small sample size. Not a study of FitGrape. Backs the cardiovascular benefit.