With so many supplements on the market, it can be hard to know what actually works. The supplement industry is vast, largely unregulated, and filled with products that make claims far exceeding the evidence supporting them. Dr. Cohen reviews the clinical evidence behind key immune-supporting supplements — including those available through Calabasas Medicine Group — to help patients make informed decisions.

The Foundation: What the Immune System Actually Needs

Before evaluating specific supplements, it is worth noting that the immune system's most fundamental requirements are met through basic lifestyle factors — adequate sleep, regular physical activity, a nutrient-dense diet, stress management, and avoidance of tobacco and excessive alcohol. No supplement can compensate for chronic sleep deprivation or a diet consistently lacking in essential nutrients.

With that foundation in place, certain supplements have meaningful evidence supporting their role in immune function — particularly in individuals with documented deficiencies or elevated physiological demands.

Vitamin D3

Vitamin D is perhaps the most well-studied nutrient in the context of immune function. Vitamin D receptors are present on virtually every immune cell, and deficiency — which is remarkably common, particularly in individuals with limited sun exposure — is associated with increased susceptibility to respiratory infections and impaired immune regulation.

Supplementation with Vitamin D3 (the most bioavailable form) has been shown in multiple studies to reduce the risk and severity of respiratory infections, particularly in individuals who are deficient at baseline. Optimal dosing should be guided by laboratory testing of 25-hydroxyvitamin D levels.

Viracid

Viracid is a professional-grade supplement formulated to support immune function during periods of acute viral challenge. It contains a combination of nutrients with established roles in immune defense, including Vitamin A, Vitamin C, Zinc, B12, pantothenic acid, and botanical extracts including elderberry, astragalus, and andrographis.

The combination of these ingredients is designed to support both innate and adaptive immune responses — providing broad-spectrum support during the early stages of illness or during periods of heightened exposure risk.

Orthomune

Orthomune is another professional-grade immune support formula that combines Vitamin C, Quercetin, Zinc, N-Acetyl Cysteine (NAC), and elderberry extract. Each of these components has independent evidence supporting its role in immune function and antioxidant defense.

Quercetin, in particular, has attracted significant research interest for its role as a zinc ionophore — facilitating the entry of zinc into cells, where it can inhibit viral replication. NAC supports glutathione production, the body's primary endogenous antioxidant, which plays an important role in immune regulation and respiratory health.

Zinc

Zinc is an essential mineral with well-established roles in immune cell development, inflammatory regulation, and antiviral defense. Deficiency is associated with impaired immune function, and supplementation in deficient individuals has been shown to improve immune response. Zinc lozenges initiated early in the course of a cold have also demonstrated modest reductions in symptom duration in clinical trials.

A Note on Quality and Individualization

Not all supplements are created equal. The quality, bioavailability, and purity of supplement products vary enormously across brands. At Calabasas Medicine Group, we offer professional-grade supplements that meet rigorous quality standards — ensuring that patients receive products that actually contain what they claim to contain, in forms the body can effectively use.

Supplement recommendations should always be individualized based on a patient's specific health status, laboratory findings, medications, and goals. What is appropriate for one patient may not be appropriate for another. We encourage patients to discuss any supplement use with Dr. Cohen to ensure safety and appropriateness within the context of their overall health plan.