HistFx -Vitamin C, Quercetin and Stinging Nettles Leaf
This product is a targeted blend of flavonoids, antioxidants, proteolytic enzymes and botanicals designed to provide comprehensive support for seasonal challenges caused by common environmental allergens. Natural D- Hist includes quercetin, a powerful flavonoid, to support healthy histamine levels. Bromelain enhances the absorption of quercetin and supports mucosal tissue health. Stinging nettles leaf balance hyper-immune response and N-acetyl cysteine clear the airways by promoting normal viscosity of mucus. This powerful combination actively promotes healthy nasal and sinus passages for individuals with elevated histamine and respiratory irritation. Also available in convenient blister packs.
Quercetin is a biologically active flavonoid antioxidant that is widely distributed in plants including oak trees, onions and tea. Quercetin has strong antioxidant activity and has been shown to support immune health by mediating the release of inflammatory compounds including leukotrienes and prostaglandins. [1,2] Quercetin is known for its ability to stabilize mast cells, diminishing the release of histamine, the compound known to cause hypersensitivity reactions during seasonal changes. 
Stinging Nettles Leaf†
Urtica dioica, commonly known as stinging nettles, is a plant that has been shown to balance immune response, specifically in the airways and nasal passages. Studies have shown that the extract of stinging nettles leaf balances a variety of inflammatory activities that affect respiratory health. Stinging nettles leaf controls mast-cell degranulation, prostaglandin formation, and histamine action all contributing to a balanced inflammatory response. 
Bromelain is a plant enzyme naturally found on the stem and fruit of the pineapple plant. Bromelain is a proteolytic enzyme that aids in in the breakdown of large protein complexes, including antigenic compounds, and has been shown to enhance the absorption of quercetin. Bromelain has been shown to reduce circulating allergenic protein complexes associated with hyper-immune sensitivity and seasonal discomfort.
N-acetyl cysteine (NAC) is an amino acid precursor to one of the most important antioxidants in the body, glutathione.  Both glutathione and NAC help reduce the viscosity of the mucus allowing for clearing of the airways and improved respiratory health. [9,10]
Vitamin C cannot be synthesized by humans and is therefore an essential nutrient that must be consumed in the diet. Among its numerous health-promoting properties, vitamin C is an essential vitamin that supports the immune system and is also a potent antioxidant. When the body is under a significant amount of stress, both emotional and environmental, vitamin C is excreted rapidly. Vitamin C has many immune boosting properties, but is distinctively beneficial for individuals with seasonal discomfort because of its ability to deactivate histamine. [11,12]
Loading Dose: 2 capsules three times per day for 7-10 days or as recommended by your health care professional.
Maintenance: 2 or more capsules per day or as recommended by health care professional.