What is the difference between grapeseed and grapeseed extract?

Grapeseed vs. Grapeseed Extract: Key Differences

Grapeseed refers to the whole seed from grapes containing approximately 5-8% polyphenols along with lipids, proteins, and carbohydrates, while grapeseed extract is a concentrated preparation that isolates and concentrates the bioactive polyphenolic compounds—primarily proanthocyanidins—into a standardized supplement form. 1

Composition and Concentration

Whole Grapeseed:

• Contains only 5-8% polyphenols by weight, with the remainder being lipids, proteins, and carbohydrates 1
• Includes the full matrix of compounds naturally present in the seed structure
• Polyphenols include gallic acid, monomeric flavan-3-ols (catechin, epicatechin, gallocatechin, epigallocatechin, epicatechin 3-O-gallate), and procyanidin oligomers 1

Grapeseed Extract:

• Represents a concentrated source of polyphenolic compounds, particularly proanthocyanidins (oligomeric proanthocyanidins) 1, 2
• Standardized preparations can deliver significantly higher concentrations of bioactive compounds per dose
• The extract is processed to remove non-polyphenolic components and concentrate the beneficial compounds 3

Bioavailability and Absorption

A critical distinction involves how these compounds behave in the body:

• Monomeric compounds (catechin and epicatechin) from both whole seeds and extracts are absorbed and appear in plasma and urine in conjugated forms 4
• Procyanidin oligomers and polymers (dimers, trimers, and higher polymers) are not bioavailable—they do not appear in detectable concentrations in plasma or urine after consumption 4
• Procyanidins are not cleaved into bioavailable monomers in the gastrointestinal tract 4
• The nutritional effects of dietary procyanidins likely occur through unabsorbed oligomers and polymers affecting the gastrointestinal tract directly, or through metabolites such as phenolic acids 4

Functional Applications

As Food Ingredients:

• Grape skin and seed extracts can be incorporated into foods as functional ingredients to inhibit advanced glycation end product (AGE) formation 3
• When added to baked goods (such as muffins at 20% concentration), grape by-products reduce harmful compound formation without significantly altering sensory profiles 3

As Dietary Supplements:

• Grapeseed extract is marketed in concentrated dose forms (pills, tablets, capsules) as defined by EFSA standards for food supplements 3
• Commercial preparations like MegaNatural Gold have demonstrated superior antioxidant activity compared to whole grapes, grape juice, or red wine 5
• Human supplementation studies show that 300 mg doses of standardized extract significantly increase plasma antioxidant capacity and improve lipid profiles in hypercholesterolemic subjects 5

Safety Profile

Both forms have demonstrated safety in toxicology studies:

• Grapeseed extract fed to rats at 2.5% of diet (equivalent to approximately 1.78-2.15 g/kg body weight/day) for 3 months showed no adverse effects, establishing this as a no-observed-adverse-effect level (NOAEL) 6
• Both grape seed extract and grape skin extract were well-tolerated without toxicologically significant changes 6

Clinical Considerations

Important caveats:

• Grapefruit extract (distinct from grapeseed) has insulin-like effects and significant drug interactions, requiring discontinuation 2 weeks before surgery 7
• Green tea extract (another polyphenol source) can be continued perioperatively, but grapeseed extract recommendations should follow general supplement guidelines 7
• The anti-glycation effectiveness of grape skin extracts has been shown to be higher than commercial nutraceutical preparations, with consistent activity across different cultivars and processing methods 3

Practical Implications

For general dietary intake: Consuming whole grapeseeds provides minimal polyphenol content (5-8%) and the procyanidins present are not systemically bioavailable 1, 4

For therapeutic or supplemental purposes: Standardized grapeseed extract provides concentrated, measurable doses of polyphenolic compounds, though the therapeutic effects may occur through mechanisms other than systemic absorption of intact procyanidins 2, 4, 5

Human studies demonstrate that 600 mg of standardized extract increases plasma antioxidant activity by 12% within 1-2 hours, equivalent to consuming 300 ml of red wine 5