Common Name(s): 3,3',4',5,7-pentahydroxyflavone,sophoretin

CAS Number: 117-39-5

DESCRIPTION

What It Does: Provides potent antioxidant protection while uniquely stabilizing mast cells to reduce allergic skin reactions and inflammation.

Why It's Used: Unique anti-allergic and anti-inflammatory flavonoid antioxidant for reactive, sensitive, and allergy-prone skin via mast cell stabilization mechanism not shared by standard antioxidants.

How It Works: Five hydroxyl groups provide superior radical scavenging via electron donation and hydrogen atom transfer. inhibits histamine release from mast cells (mast cell stabilization). blocks 5-lipoxygenase and cox-2 for anti-inflammatory activity. chelates metal ions. inhibits tyrosinase for brightening.

Typically Found In: Sensitive skin products,anti-aging serums,redness relief formulations

TECHNICAL DETAILS

Primary Category: Active ingredient – flavonoid antioxidant

Secondary Functions: Mast cell stabilization,anti-allergic,anti-inflammatory

Application Areas:

Typical Concentration Range: 0.1%–2%

SOURCING & ETHICS

Vegan Status: Yes – plant-derived (capers, onion, elderberry, quercetin-rich foods)

Halal Status: Yes

Source Notes: Extracted from sophora japonica flowers, quercus species bark, or synthesized. poorly water-soluble – requires encapsulation or liposomal delivery.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; well-tolerated.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Vitamin c,vitamin e,ferulic acid,spf,other antioxidants

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Quercetin's mast cell stabilization (preventing degranulation and histamine/cytokine release) is a mechanism absent from most antioxidants. this anti-mast cell activity makes quercetin uniquely effective for inflammatory skin conditions where mast cell hyperactivation (rosacea, urticaria, atopic dermatitis) drives reactivity.

Last Verified: Cosing database,griffiths et al. quercetin anti-inflammatory review,cir safety assessment

Primary Sources: 2026-03-12