Quercetin & Bromelain and Immune Health

—a little about a lot


Researchers' findings suggest that Quercetin may support the immune system when exposed to viral stressors by functioning to:

  • support immune defenses by working to impede the initial stages of virus infection through interactions with viral proteins.*
  • balance immune functions associated with outside stressors through antioxidant action in support of the body's natural defenses against oxidative stress.* 


The protein-digesting enzyme Bromelain is well studied for its antioxidant properties, support of seasonal respiratory comfort, wound healing, and recovery.*

Studies suggest that Bromelain may play a more regulatory role in support of our immune system's defenses, where our immune system is able to utilize Bromelain to support different immune responses depending on the cell's microenvironment and health.* 

In essence, Bromelain may be a multifunctional tool our natural defenses are able to call upon, depending on the need.*

Controversially, some studies have found that intense exercise can make us temporarily more vulnerable to viral infections.

Interestingly, one small Quercetin supplementation study found that Quercetin may help to support the immune system during this short window of recovery.*

The study looked at 40 male cyclists, where 45% of participants in the placebo group fell ill after a tough 3-day exercise regime, while only 5% of the men taking Quercetin fell ill during that same 14-day time period.*

Living cells produce an array of highly active oxygen-derived free radicals in their daily functions, which can damage tissue if not addressed swiftly.

To prevent damage from occurring within the body, our natural defense mechanisms are constantly working to synthesize antioxidants in order to counterbalance these reactive molecules.

When the generation of these free radicals becomes too high, and for any reason, there aren't enough antioxidants to counter them, we enter into a state known as 'oxidative stress.'

Research suggests that Quercetin may function to support healthy antioxidant levels throughout the body, including the respiratory system, and as a result, supports immune health and resilience when exposed to environmental stressors.*

Laboratory and animal studies suggest that both Quercetin and Bromelain may support respiratory comfort by helping to promote a more balanced immune response to daily and seasonal stressors.*

A recent four-week, 66-participant study in Japan highlighted these findings. With daily Quercetin supplementation, researchers saw significant improvement in respiratory comfort over the placebo group.*

Beyond the Bullet Points

Dig deeper into the literature evolving around Quercetin & Bromelain, and immune health.

Di Petrillo, A., Orrù, G., Fais, A., & Fantini, M. C. (2022). Quercetin and its derivates as antiviral potentials: A comprehensive review.Phytotherapy Research,36(1), 266-278. Link

Hikisz, P., & Bernasinska-Slomczewska, J. (2021). Beneficial properties of bromelain.Nutrients,13(12), 4313. Link

Jafarinia, M., Sadat Hosseini, M., Kasiri, N., Fazel, N., Fathi, F., Ganjalikhani Hakemi, M., & Eskandari, N. (2020). Quercetin with the potential effect on allergic diseases.Allergy, Asthma & Clinical Immunology,16, 1-11. Link

Kumar, P., Khanna, M., Srivastava, V., Tyagi, Y. K., Raj, H. G., & Ravi, K. (2005). Effect of quercetin supplementation on lung antioxidants after experimental influenza virus infection.Experimental lung research,31(5), 449-459. Link

Li, Y., Yao, J., Han, C., Yang, J., Chaudhry, M. T., Wang, S., ... & Yin, Y. (2016). Quercetin, inflammation and immunity.Nutrients,8(3), 167. Link

Nieman, D. C., Henson, D. A., Gross, S. J., Jenkins, D. P., Davis, J. M., Murphy, E. A., ... & Mayer, E. P. (2007). Quercetin reduces illness but not immune perturbations after intensive exercise.Medicine & Science in Sports & Exercise,39(9), 1561-1569. Link

Secor, E. R., Carson, W. F., Singh, A., Pensa, M., Guernsey, L. A., Schramm, C. M., & Thrall, R. S. (2008). Oral bromelain attenuates inflammation in an ovalbumin-induced murine model of asthma.Evidence-based Complementary and Alternative Medicine,5(1), 61-69. Link

Varilla, C., Marcone, M., Paiva, L., & Baptista, J. (2021). Bromelain, a group of pineapple proteolytic complex enzymes (Ananas comosus) and their possible therapeutic and clinical effects. A summary.Foods,10(10), 2249. Link

Yamada, S., Shirai, M., Inaba, Y., & Takara, T. (2022). Effects of repeated oral intake of a quercetin-containing supplement on allergic reaction: a randomized, placebo-controlled, double-blind parallel-group study.Eur Rev Med Pharmacol Sci,26(12), 4331-4345. Link