Isoquercetin
INCI: ISOQUERCETIN
Reviewed by Rosie · Last updated 14 Aug 2026
A glycosylated flavonoid with antioxidant and soothing potential
Best For Skin Types
All, Sensitive, Mature
Addresses
Usage Frequency
Daily
What Is Isoquercetin?
Isoquercetin is a naturally occurring flavonoid—a type of plant compound found in various herbs and foods. It is the glycosylated form of quercetin, meaning a sugar molecule is chemically bound to the quercetin structure. This modification is significant because it may enhance bioavailability and stability compared to quercetin alone, allowing the ingredient to be more readily available to skin cells.
In skincare formulations, isoquercetin functions as an antioxidant and anti-inflammatory agent. It works to neutralise free radicals and may help modulate inflammatory pathways in the skin, making it relevant for conditions characterised by oxidative stress and inflammation.
Benefits for Your Skin
How It Works
Isoquercetin exerts its effects primarily through its antioxidant capacity—it donates electrons to neutralise free radicals before they can damage skin cells and collagen. Additionally, the ingredient appears to modulate inflammatory signalling pathways by reducing the production of pro-inflammatory cytokines (chemical messengers that trigger inflammation).
The glycoside structure may offer advantages over non-glycosylated quercetin by improving how efficiently the ingredient penetrates the skin and is utilised at a cellular level. This enhanced bioavailability means the ingredient may be more effective at lower concentrations.
Clinical Evidence & References
Preclinical research suggests isoquercetin has biological activity against multiple pathways involved in skin ageing, including oxidative stress, inflammation, and collagen degradation. In vitro and ex vivo studies have shown it can upregulate antioxidant defence genes and suppress the production of inflammatory markers like IL-6 and IL-8 in human skin cells.
Research on quercetin glycosides (including isoquercetin) indicates potential anti-inflammatory benefits for atopic dermatitis-like lesions, with the glycosylated forms showing improved skin absorption and bioactivity compared to non-glycosylated quercetin. However, most evidence to date comes from laboratory and animal studies rather than robust human clinical trials, so the strength of benefit in real-world use remains to be fully established.
Published Research
How to Use
Isoquercetin is typically used as part of serums, moisturisers, or treatment products applied to clean skin once or twice daily. It pairs well with other antioxidants and anti-inflammatory ingredients such as vitamin E, vitamin C, or niacinamide. As with any new skincare ingredient, introduce it gradually and observe how your skin responds over several weeks before drawing conclusions about efficacy.
Safety & Precautions
Frequently Asked Questions
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