1 Bottle of Fierce Immunity

Vitamin D is obtained from sun exposure, foods, and supplements. These sources supply vitamin D in a biologically inactive form. When activating vitamin D, the liver and the kidney transform the inactive form into the physiologically active form, known as calcitriol.

Fierce Immunity is designed to help activate vitamin D and increase calcitriol production. And, unlike other vitamin D supplements, the addition of quercetin can help increase the bioavailability of vitamin D, and arginine can help increase its efficacy.

The correlation between a Th1/Th2 cytokines imbalance and vitamin D level in patients with early chronic obstructive pulmonary disease (COPD), based on screening results (link).

Vitamin D Regulation of Immune Function (link).

The influence of vitamin D on M1 and M2 macrophages in patients with Crohn's disease (link).

Zinc ascorbate is the zinc salt of vitamin C. It has superoxide dismutase-like and antibacterial activity. The combination of zinc and vitamin C supports the innate immune system only when consumed in moderate amounts. Too much zinc weakens, rather than strengthens, the innate immune system.

This function can help increase the efficacy of quercetin and hesperidin, as well as the immune-supporting power of Fierce Immunity.

Clinical efficacy of zinc supplementation in improving antioxidant defense system: A comprehensive systematic review and time-response meta-analysis of controlled clinical trials (link).

Zinc supplementation reduces Candida infections in pediatric intensive care unit: a randomized placebo-controlled clinical trial (link).

Inflammatory response under zinc deficiency is exacerbated by dysfunction of the T helper type 2 lymphocyte-M2 macrophage pathway (link).

Quercetin, a flavonol found in many fruits and vegetables, not only kills bacteria and viruses, but also supports the immune system by increasing the production of immune effector cells. Combined with hesperidin, quercetin can help protect memory functions and slow cognitive decline. 

Since quercetin also can increase the oral bioavailability of vitamin D and support its activation, it can help increase the protective power of vitamin D. Additionally, quercetin can help regulate overproduction of nitric oxide from the I-arginine in Fierce Immunity.

Modulation of Th1/Th2 Cytokine Balance by Quercetin In Vitro (link).

Quercetin, Inflammation and Immunity (link).

Neuroprotective Potentials of Flavonoids: Experimental Studies and Mechanisms of Action (link).

Influence of the Neuroprotective Properties of Quercetin on Regeneration and Functional Recovery of the Nervous System (link).

Regulatory Effects of Quercetin on M1/M2 Macrophage Polarization and Oxidative/Antioxidative Balance (link).

Hesperidin, a flavanone contained in citrus fruits, is a time-honored herbal medicine that was first isolated in 1828. By reducing viral replication, it helps protect against influenza. Hesperidin can reduce inflammation, support the production of immune effector cells, and more.

The safety of hesperidin was confirmed by FASEB (Federation of American Societies of Experimental Biology) upon request of the FDA. Toxicity studies have confirmed the high safety profile of hesperidin after oral intake.

FDA GRAS notices for hesperidin (link).

ChEBI: Hesperidin (link).

Experimental immunology - Differential effect of hesperidin on Th1, Th2, Th17, and proinflammatory cytokines production from splenocyte of Schistosoma mansoni-infected mice (link).

Hesperidin as a Neuroprotective Agent: A Review of Animal and Clinical Evidence (link).

Hesperidin inhibits synovial cell inflammation and macrophage polarization through suppression of the PI3K/AKT pathway in complete Freund's adjuvant-induced arthritis in mice (link).

Orange juice and hesperidin promote differential innate immune response in macrophages ex vivo (link).

L-arginine serves as a building block for proteins and plays an essential role in the immune and cardiovascular systems. This amino acid is essential to nitric oxide production in the body, which can improve blood flow and heart health.

L-arginine can increase the activation of vitamin D, which is designed to help increase the ability of Fierce Immunity to unlock the immune system’s full potential.

Intravenous arginine administration benefits CD4+ T-cell homeostasis and attenuates liver inflammation in mice with polymicrobial sepsis (link).

Arginine-dependent immune responses (link).

Effect of L-arginine on immune function: a meta-analysis (link).

Functional characterization of nutraceuticals using spectral clustering: Centrality of caveolae-mediated endocytosis for management of nitric oxide and vitamin D deficiencies and atherosclerosis (link).