Houttuynia cordata flower/leaf extract

// Evidence: Antioxidants prevent or delay oxidation by donating electrons to free radicals, chelating pro-oxidant metals, or regenerating other antioxidants. Mechanisms include direct radical scavenging (vitamin E, vitamin C, BHT, BHA), metal chelation (EDTA), or enzymatic action. On skin, they neutralize reactive oxygen species (ROS) generated by UV radiation and pollution, preventing lipid peroxidation and DNA damage.

// Evidence: Humectant ingredients draw water from the environment and deeper skin layers through hygroscopic properties. Common humectants include glycerin, propylene glycol, hyaluronic acid, urea, and alpha-hydroxy acids. These contain multiple hydroxyl groups or other hydrophilic functional groups that form hydrogen bonds with water molecules. Mechanism involves attracting water to the stratum corneum, reducing transepidermal water loss, and increasing skin hydration.

// Evidence: Skin conditioning ingredients enhance appearance, texture, and health of skin through various mechanisms. This broad category encompasses emollients, humectants, occlusives, and other agents that improve skin feel, appearance, and function. May work by moisturizing, smoothing, softening, or protecting skin. Effects include improved tactile properties, enhanced barrier function, and better overall skin condition.

// Evidence: Emollient ingredients create smooth, soft skin by filling spaces between corneocytes in stratum corneum. These include esters (isopropyl palmitate), oils (jojoba, argan), fatty alcohols, and silicones. The mechanism involves spreading on skin surface, filling microscopic irregularities, and creating lubricious film. Effects are immediate tactile improvement and visual smoothing. Emolliency measured by spreading coefficient and skin feel assessments.