Summer sun. Evening walks. And… mosquito bites. 🦟 - just seeing this emoji probably makes you itch. That telltale itch isn't just annoying, it's your immune system in overdrive. What if you could quiet the inflammation using the power of plants?

At MARK Los Angeles, we turn to flavonoids — baicalein, fisetin, luteolin, and quercetin — to help interrupt the itch response before it spirals. These four flavonoids are in our XDF-4 After Bite Serum. Here's how it works.

What Makes a Mosquito Bite Itch?

When a mosquito bites, it injects saliva that triggers an immune reaction. Mast cells rush to the scene and release histamine, a key chemical that causes itching, swelling, and redness. Histamine is just the beginning.

Your skin's immune system also ramps up pro-inflammatory cytokines like:

IL-4 and IL-13 – drive allergic inflammation
IL-31 – a major "itch" signal that sensitizes nerve endings
TNF-α and IL-6 – create redness and prolong swelling

All of this means that even a tiny bite can feel like a big deal.

Flavonoid Power: Baicalein, Fisetin, Luteolin, and Quercetin

Baicalein

A flavone derived from Scutellaria baicalensis (Chinese skullcap)
Helps stabilize mast cells, tempering histamine release
Inhibits inflammatory signaling, including lipoxygenase-driven pathways
Calms oxidative stress at the bite site

Fisetin

A flavonol found in strawberries and other fruits
Modulates NF-κB signaling, a master switch for inflammatory cytokines
Helps quiet TNF-α and IL-6 activity
Supports the skin's recovery after immune activation

Luteolin

A flavone found in celery, parsley, and chamomile
Stabilizes mast cells and helps blunt histamine release
Inhibits IL-6 and TNF-α, easing redness and swelling
Studied for calming itch-related nerve sensitization

Quercetin

Found in apples, red onions, and capers
Acts as a natural antihistamine
Suppresses IL-4 and IL-13, calming the Th2-type immune response
Reduces itch-related nerve sensitivity

Together, baicalein, fisetin, luteolin, and quercetin in our XDF-4 After Bite Serum address both the cause and the sensation of a mosquito bite: calming immune overreaction and reducing the skin's response to histamine.

Why We Deliver Flavonoids Differently

Flavonoids are notoriously hard to absorb through the skin. That's why we use XDF™, our transdermal flavosome delivery system, to bring this four-flavonoid blend deeper into the skin where inflammation starts.

No sticky menthol. No steroids. Just plant active ingredients.

Bottom Line

If you're looking for a smarter way to soothe summer skin, flavonoids like baicalein, fisetin, luteolin, and quercetin offer targeted, calming relief. Whether it's a mosquito bite, a mystery rash, or just a little overexposure, the plant world has you covered and MARK Los Angeles delivers it where it counts.

References

Kimata M, et al. "Effects of luteolin, quercetin and baicalein on immunoglobulin E-mediated mediator release from human cultured mast cells." Clinical & Experimental Allergy. 2000;30(4):501–508.

Kim S-H, et al. "Fisetin inhibits IL-31 production in stimulated human mast cells: possibilities of fisetin being exploited to treat histamine-independent pruritus." Life Sciences. 2018;200:22–30.

Park SJ, et al. "Luteolin suppresses IL-31 production in IL-33-stimulated mast cells through MAPK and NF-κB signaling pathways." International Immunopharmacology. 2020.

Kang OH, et al. "Luteolin isolated from the flowers of Lonicera japonica suppresses inflammatory mediator release by blocking NF-κB and MAPKs activation pathways in HMC-1 cells." Molecules. 2010;15(1):385–398.

Weng Z, et al. "Quercetin is more effective than cromolyn in blocking human mast cell cytokine release and inhibits contact dermatitis and photosensitivity in humans." PLoS One. 2012;7(3):e33805.