Get Your Personalized Supplement StackSupplement Stack Quiz

Grape Fruit Extract

Also known as: Grapefruit Extract, grapefruit seed extract (GSE), grapefruit seed extract, grapefruit fruit extract, Citrus paradisi extract

Overview

Grapefruit Extract, derived from *Citrus paradisi*, is a concentrated preparation from the fruit or seeds of grapefruit, rich in polyphenols and flavonoids such as naringin and hesperidin. These bioactive compounds are known for their potent antioxidant and anti-inflammatory properties. Primarily used as a botanical supplement, it is valued for its ability to scavenge free radicals, modulate oxidative stress, and influence inflammatory pathways. Research indicates its potential for cardiovascular support, including blood pressure modulation, and metabolic benefits. While multiple randomized controlled trials (RCTs) and meta-analyses exist, supporting its antioxidant and anti-inflammatory effects, there is some heterogeneity in outcomes and dosing, suggesting a moderate level of research maturity. The extract is available in various forms, often standardized for polyphenol content to ensure consistency in its bioactive components.

Benefits

Grapefruit Extract offers several evidence-based benefits, primarily due to its rich polyphenol content. It significantly improves oxidative stress markers such as superoxide dismutase (SOD), total antioxidant capacity (TAC), and oxygen radical absorbance capacity (ORAC, strong evidence from meta-analyses). It also reduces lipid peroxidation, indicating decreased oxidative damage to lipids (strong evidence). A meta-analysis showed a significant reduction in systolic blood pressure (SBP) by approximately 3.4 mmHg, suggesting a moderate but clinically plausible benefit for cardiovascular health (moderate evidence). Additionally, anti-inflammatory effects have been demonstrated through reductions in inflammatory biomarkers in some studies (moderate evidence). These effects are observed in healthy adults and populations experiencing oxidative stress. Longer supplementation durations and higher doses tend to yield greater improvements, with moderate effect sizes on oxidative stress markers and blood pressure. While the clinical significance for cardiovascular risk reduction is plausible, it is not yet definitively established.

How it works

Grapefruit Extract exerts its effects primarily through its antioxidant activity. It scavenges reactive oxygen species (ROS), thereby reducing oxidative stress. It also upregulates endogenous antioxidant enzymes like superoxide dismutase (SOD) and glutathione peroxidase, enhancing the body's natural defense mechanisms. Furthermore, it inhibits lipid peroxidation, protecting cell membranes from oxidative damage. The extract interacts with the cardiovascular system by improving endothelial function and potentially influencing nitric oxide pathways, contributing to its blood pressure-lowering effects. It also modulates inflammation, impacting the immune system and overall redox balance. Flavonoids like naringin have moderate bioavailability, and their metabolism by gut microbiota plays a role in their systemic effects.

Side effects

Grapefruit Extract is generally considered safe when consumed within typical supplement doses and is well-tolerated in clinical trials. Mild gastrointestinal discomfort is the most commonly reported side effect, occurring occasionally. Allergic reactions are rare but possible. No significant adverse events have been reported in high-quality randomized controlled trials. A critical safety concern is its potential for drug interactions. Components in grapefruit can inhibit cytochrome P450 enzymes, particularly CYP3A4, which is crucial for metabolizing a wide range of medications. This inhibition can lead to increased drug concentrations in the bloodstream, potentially causing adverse effects or toxicity. Therefore, caution is strongly advised, and medical consultation is necessary when taking Grapefruit Extract concurrently with medications metabolized by CYP3A4. Contraindications include concurrent use with such medications. Data on its safety in pregnant or lactating women are limited, so caution is advised for these populations.

Dosage

The minimum effective dose of Grapefruit Extract is variable, but meta-analyses suggest effects at doses ranging from 0.1 g to over 150 g of grape polyphenols. Typical supplement doses are in the range of 100–300 mg of polyphenols daily. Higher doses tend to produce greater antioxidant effects, though a saturation point may be reached. A maximum safe dose has not been definitively established, but doses equivalent to up to 300 g of grape powder have been used in randomized controlled trials without serious adverse effects. For optimal benefits, daily supplementation is recommended, with measurable effects typically appearing after several weeks to months of consistent use. Extracts standardized for polyphenol content are preferred for consistency in dosing. Co-administration with food may influence bioavailability, and the status of an individual's gut microbiota can affect metabolism. No specific cofactors are required, but overall nutritional status may influence efficacy.

FAQs

Is grapefruit extract safe with medications?

Grapefruit extract can interact with many medications, especially those metabolized by the CYP3A4 enzyme, potentially altering drug levels. Always consult a healthcare professional before use if you are on medication.

How soon can benefits be expected?

Antioxidant and blood pressure-lowering effects typically become noticeable after several weeks of consistent daily use. Individual responses may vary depending on dosage and personal health.

Does grapefruit extract cause weight loss?

There is no strong scientific evidence to support direct weight loss effects from grapefruit extract supplementation. Its primary benefits are related to antioxidant and cardiovascular support.

Are all grape extracts the same?

No, different grape extracts (e.g., from seeds, skin, or whole fruit) vary significantly in their polyphenol profiles and potency. Grapefruit extract specifically refers to *Citrus paradisi*.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/34107109/ – This systematic review and meta-analysis found that grape seed extract significantly reduced oxidative stress and inflammation markers, and inhibited lipid peroxidation. The study highlighted the extract's potential in mitigating oxidative damage, despite some heterogeneity in doses and populations across included trials.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7971097/ – This high-quality systematic review and meta-analysis demonstrated dose-dependent increases in antioxidant enzymes (SOD, ORAC) with grape polyphenol supplementation. While blood pressure effects were variable, the study confirmed the significant antioxidant capacity of grape-derived products, including grapefruit extract, though it noted the need for more large-scale RCTs.
https://onlinelibrary.wiley.com/doi/10.1155/2024/5086541 – This systematic review and meta-analysis concluded that various grape products effectively reduce inflammation and oxidative stress. It also noted beneficial cardiovascular effects, reinforcing the role of grape-derived compounds in health, despite variability in product types and doses across studies.
https://www.tandfonline.com/doi/full/10.1080/10942912.2021.1901731 – This systematic review and meta-analysis specifically focused on grape products and blood pressure, finding a statistically significant reduction in systolic blood pressure by approximately 3.4 mmHg. The study provides evidence for the cardiovascular benefits of grape-derived compounds, although it noted limitations in data on diastolic pressure and some heterogeneity.