Immune-Boosting Protocols

There’s no question that a strong immune system is paramount these days. Between Covid and your run-of-the-mill seasonal cold and flu, our system has its work cut out for it. It’s advised to provide more fuel for fighting sickness, so we’ve compiled a list of our go-to immune boosters. As always, if you have specific questions or concerns, please reach out to us.

(daily adult dosage)

  • 5000 IU vitamin D3
  • 500 mg vitamin C
  • 15 mg zinc
  • 250 mg quercetin
  • Andrographis 300 to 400 mg

(adult dosage at symptom onset)

  • 25,000 IU D3
    (single megadose, 5000 IU daily thereafter)
  • 2000 mg vitamin C in divided doses
    (500 mg per dose)
  • 30 to 60 mg zinc in divided doses
    (15 or 30 mg per dose)
  • 500 mg quercetin
    (250 mg per dose paired with zinc)
  • Andrographis 600 to 900 mg in divided doses
  • N-acetyl Cysteine 500 to 1500 mg
    (~500 mg per dose)

Vitamin D3

Vitamin D3 is a pre-hormone, which acts as a catalyst for metabolism and immune response. Higher blood levels of vitamin D are associated with better outcomes in infected patients.

Vitamin C

Vitamin C (ascorbic acid) is a water-soluble antioxidant and assists in the function of immune cells. Due to our limited capacity for absorption of vitamin C, doses should be limited to 500 mg or less per serving.


Zinc is an essential trace mineral necessary for the growth and proper function of immune cells. Because our bodies do not store zinc in significant quantities, daily intake is needed for optimum health.


Quercetin, a flavonoid found in many plants, has remarkable antiviral and immune-supportive properties. When taken with zinc, quercetin can assist in delivering that mineral to appropriate tissues.


Andrographis is a bitter herb with a long history of use in Ayurvedic medicine. It is an immune stimulant, as well as having direct antimicrobial effects. The anti-inflammatory effects of Andrographis may also prove useful in cases of prolonged infection.

N-acetyl Cysteine (NAC)

N-acetyl Cysteine (NAC) is a multi-faceted amino acid. An antioxidant, mucolytic as well as a precursor to glutathione, NAC helps improve liver function and encourages clearance of mucus from the lower respiratory system.

Related Studies

Vitamin D high doses supplementation could represent a promising alternative to prevent or treat COVID-19 infection

Mini-Review on the Roles of Vitamin C, Vitamin D, and Selenium in the Immune System against COVID-19

Quercetin and Vitamin C: An Experimental, Synergistic Therapy for the Prevention and Treatment of SARS-CoV-2 Related Disease (COVID-19)

Zinc and immune function: the biological basis of altered resistance to infection

The Role of Adaptogens in Prophylaxis and Treatment of Viral Respiratory Infections

Anti-SARS-CoV-2 Activity of Andrographis paniculata Extract and Its Major Component Andrographolide in Human Lung Epithelial Cells and Cytotoxicity Evaluation in Major Organ Cell Representatives

N-Acetylcysteine: A potential therapeutic agent for SARS-CoV-2

Rationale for the use of N‐acetylcysteine in both prevention and adjuvant therapy of COVID‐19

Printable Guides

Tips for Enhancing Immunity - Handout Download

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About the Author

Joel Hall

Coastal Pharmacy & Wellness Staff

At Coastal, Joel is our go-to guy for anything related to supplementation and the complex role nutrients play in every bodily function. Although he may be reserved, helping people find their way to optimal health drives what he does. If you see him staring intently at his computer screen, he’s most likely researching something that most of us can only partly understand. He loves sharing his accumulated knowledge and spends as much time as necessary to explain things in a way to help you make good health decisions. He's been working in the wellness arena since the early 2000's and has been in the pursuit of nutritional knowledge since way before that. You can find him behind the wellness desk Tuesdays through Saturdays. For more information read our profile on Joel.

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