Overview
Dihydroquercetin (DHQ), also known as taxifolin, is a flavonoid with potent antioxidant and anti-inflammatory properties. It has been studied for its potential cardiovascular and metabolic benefits, largely due to its ability to enhance endothelial function and increase nitric oxide (NO) bioavailability, which may contribute to blood pressure regulation [4]. While most clinical research has focused on quercetin, DHQ shares structural and functional similarities, including modulation of oxidative stress and inflammation pathways implicated in cardiovascular and neurodegenerative diseases [2][3]. Animal and in vitro studies suggest DHQ may offer superior bioavailability and antioxidant capacity compared to quercetin, though human clinical trials are limited. Evidence for lipid-lowering or antihypertensive effects remains preliminary, and no large-scale phase III trials have confirmed therapeutic efficacy in humans [3][1].
Dosage Guide
Therapeutic Doses
For treatment of specific conditions
Upper Intake Limit
Maximum safe daily intake
1000 mg— No established UL for DHQ; 1 g/day used in short-term studies without adverse effects, but long-term safety unknown
Special Forms
Alternative forms for specific needs
Common natural source with enhanced bioavailability in lipid-based formulations
Emerging form designed to improve stability and cellular uptake
Clinical Notes
- Limited human safety data beyond short-term use; theoretical risk of pro-oxidant effects at very high doses [6]
- Potential interaction with cytochrome P450 enzymes and drug metabolism; use caution with anticoagulants, antihypertensives, or chemotherapy agents
- Pregnancy and lactation: Insufficient data to establish safety; avoid high-dose supplementation
- Monitor for gastrointestinal discomfort at higher doses
Research
Quercetin supplementation showed modest reductions in blood pressure in a meta-analysis of RCTs, particularly at doses ≥500 mg/day.
Quercetin exhibits multiple physiological actions, including anti-inflammatory, antioxidant, and potential anticancer effects, though clinical translation remains limited.
Meta-analysis of RCTs found no significant effect of quercetin on total cholesterol, LDL-C, HDL-C, or triglycerides.
Acute administration of quercetin-3-O-glucoside improved endothelial function and reduced BP in a dose-dependent manner, with peak effects at moderate doses.
Highlights the importance of conducting phase II dose-finding studies before large phase III trials for dietary supplements to optimize efficacy and resource use.
Reviews potential toxicity of flavonoids, noting that while generally safe, high doses may pose risks including pro-oxidant effects and endocrine disruption.
Emphasizes the need for rigorous clinical trials to distinguish true efficacy from placebo effects in dietary supplements.
