Last verified: today
Grape Juice Concentrate
Also known as: GJC, G8000, red grape juice concentrate, Vitis vinifera juice concentrate
Evidence under review. — Not yet rated
Antioxidant-rich grape extract. Animal studies suggest protective effects, but no human trials exist.
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What it does
Grape juice concentrate is a polyphenol-rich extract made from grapes, containing flavonoids and other antioxidant compounds. In animal studies, it has shown protective effects against oxidative...
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Evidence quality
Evidence base hasn't been formally rated yet. See research below.
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Clinical dose
No established dose (insufficient research data)
What the Science Says
Grape juice concentrate is a polyphenol-rich extract made from grapes, containing flavonoids and other antioxidant compounds. In animal studies, it has shown protective effects against oxidative damage in the liver, testes, and colon when animals were exposed to toxic chemicals like cadmium. These effects appear to work through antioxidant and anti-inflammatory pathways, including boosting enzymes like superoxide dismutase and reducing inflammatory markers like COX-2 and TNF-alpha. No human clinical trials from the provided research confirm these effects in people.
What It Doesn't Do
Not proven to protect human organs from toxins. No human evidence it boosts fertility or sperm health. No clinical proof it prevents cancer in people. Don't assume rat study results translate to humans — they often don't. Not a treatment for inflammatory bowel disease in people.
Evidence-Based Benefits
Reduces oxidative DNA damage and boosts antioxidant enzymes in rats exposed to toxic chemicals.
Weak EvidenceEffective at: No established human dose
Reduces liver tissue damage caused by cadmium toxicity in rat studies.
Weak EvidenceEffective at: No established human dose
Lowers inflammatory markers like COX-2 and TNF-alpha in rat models of colitis and oral cancer.
Weak EvidenceEffective at: No established human dose
Protects sperm count, morphology, and testosterone levels in cadmium-exposed male rats.
Weak EvidenceEffective at: No established human dose
Absorption & Bioavailability
Unknown — no human pharmacokinetic data in the provided studies. Animal studies used oral gavage delivery.
Red Flags to Watch For
- All supporting research is in rats, not humans — effects may not translate
- No established safe or effective dose for humans exists based on provided data
- Cadmium-protection studies used injected cadmium toxicity, an extreme model unlikely to reflect normal human exposure
- Products containing grape juice concentrate are widely sold (1000+ registered products) despite a near-total absence of human clinical trial data
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-05-25