Is Grape Seed Extract safe?
Pro Research Analysisby 
Searched over 200M research papers
Safety of Grape Seed Extract: A Comprehensive Review
Introduction to Grape Seed Extract Safety
Grape seed extract (GSE) is widely recognized for its health benefits, including antioxidant, anti-inflammatory, and antimicrobial properties. However, its safety profile is crucial for its use as a dietary supplement and in food products. This article synthesizes findings from multiple studies to evaluate the safety of GSE.
90-Day Oral Toxicity in Rats
A 90-day oral toxicity study on Sprague-Dawley rats assessed the safety of GSE with less than 5.5% catechin monomers. Rats were fed diets containing 0.5%, 1.0%, or 2.0% GSE. The study found no significant changes in clinical signs, hematological parameters, organ weights, ophthalmology evaluations, or histopathological findings. Although male rats in the high-dose group exhibited decreased serum iron levels, these values remained within historical ranges for the species. The study concluded that GSE did not induce significant toxicological effects at the tested levels1.
4-Week Oral Intake in Humans
A clinical study involving healthy Japanese adults evaluated the safety of proanthocyanidin-rich GSE over four weeks. Participants consumed daily doses of 1000, 1500, or 2500 mg. While two subjects in the highest dose group experienced a temporary decrease in serum iron levels, these levels returned to near baseline after the study. No participants discontinued the study, indicating that GSE up to 2500 mg per day is generally safe and well-tolerated in humans2.
Subchronic Toxicity Studies
Subchronic toxicity studies on Fischer 344 rats involved administering GSE at levels of 0.02%, 0.2%, and 2% in the diet for 90 days. The studies found no evidence of acute oral toxicity or mutagenicity. The no-observed-adverse-effect level (NOAEL) was determined to be 2% in the diet, equivalent to 1410 mg/kg body weight/day in males and 1501 mg/kg body weight/day in females3. Another study on Sprague-Dawley rats fed diets containing up to 2.5% GSE for three months also reported no treatment-related toxicological changes, supporting the safety of GSE at these levels8.
Acute and Genotoxicity Tests
Acute oral toxicity tests determined that the lethal dose 50 (LD50) of GSE is higher than 5000 mg/kg. Genotoxicity tests, including the bacterial reverse mutation test and chromosomal aberration test, showed no significant mutagenic effects at tested doses. These findings suggest that GSE is not acutely toxic and has a low risk of genotoxicity5.
Safe Dosage in Mice
A pilot study on albino mice assessed the safety of black and red GSE at doses of 200, 400, and 800 mg/kg body weight. The study found that doses of 200 and 400 mg/kg were safe, while the 800 mg/kg dose led to reduced body weight gain and organ changes. This indicates that lower doses of GSE are safe, but higher doses may pose risks9.
Conclusion
The collective findings from various studies indicate that grape seed extract is generally safe for consumption at specified doses. Both animal and human studies support the safety of GSE, with no significant toxicological effects observed at typical consumption levels. However, higher doses may lead to minor adverse effects, such as temporary changes in serum iron levels. Further research with larger sample sizes and longer durations is recommended to confirm these findings and establish comprehensive safety guidelines.
Sources and full results
Most relevant research papers on this topic
90-day oral toxicity study of a grape seed extract (IH636) in rats.
Grape seed extract IH636 at levels of 0.5, 1.0, or 2.0% for 90 days did not induce significant toxicological effects in male and female Sprague-Dawley rats.
Highly CitedSafety assessment of 4-week oral intake of proanthocyanidin-rich grape seed extract in healthy subjects.
Oral intake of up to 2500 mg of proanthocyanidin-rich grape seed extract for 4 weeks is generally safe and well tolerated in healthy individuals.
Non-RCTSafety evaluation of proanthocyanidin-rich extract from grape seeds.
Proanthocyanidin-rich extract from grape seeds shows no evidence of toxicity and is safe for use in various foods.
Non-RCT
Animal StudyHighly CitedBlessings in disguise: Bio-functional benefits of grape seed extracts
Grape seed extracts, a by-product of the wine industry, show potential health benefits due to their anti-oxidant, anti-cancer, antimicrobial, anti-aging, and anti-hepatotoxic properties.
Literature ReviewToxicology evaluation of a procyanidin-rich extract from grape skins and seeds.
The procyanidin-rich extract from grape seeds and skins (GSSE) shows slight mutagenicity, but further studies are needed to confirm its safety for incorporation into functional foods.
Non-RCTAnimal StudyGreen tea and grape seed extracts — Potential applications in food safety and quality
Green tea and grape seed extracts show potential in enhancing food safety and quality by inhibiting lipid oxidation and preventing pathogen contamination.
Highly CitedGrape seed extract: having a potential health benefits
Grape seed extract, rich in proanthocyanidins, shows potential health benefits against various diseases, making it a potential nutraceutical or cosmeceutical for future pharmaceutical formulations.
Literature ReviewHighly CitedSubchronic 3-month oral toxicity study of grape seed and grape skin extracts.
Grape seed and grape skin extracts, containing proanthocyanidins, are safe for human consumption at a 2.5% concentration, with no observed adverse effects in a 3-month subchronic toxicity study.
Non-RCTAnimal StudyHighly CitedClinical and Histopathological study of black and red grape seed extracts (Vitis Vinifera) effects on the Albino Mice
200 and 400mg/kg b.w. doses of grape seed extract are safe for mice, while 800mg/kg b.w. is toxic due to reduced body weight gain and changes in organs.
RCTAnimal StudyInhibitory effects of grape seed extract on lipases.
Grape seed extract, rich in phytochemicals, may provide a safe, natural, and cost-effective weight control treatment by inhibiting fat-metabolizing enzymes.
In Vitro StudyHighly CitedTry another search
How much Licorice Root should I take daily?
What are the future of genetic engineering in humans?
What are the future of artificial organs?
How can I reduce the risk of developing type 2 diabetes?
What causes the sound of a zebra braying?
what are the learning tendencies regarding new universities to teach stem, digital art, metaverse, r