Why does elderberry boost the immune system?: The science behind this popular supplement

October 8, 2025 •

3 min read

For centuries, elderberry has been a staple in folk medicine to treat colds and flu, and today, sales of elderberry supplements continue to climb. Many people wonder, however, why does elderberry boost the immune system and what specific compounds are responsible for this effect? The answer lies in a multi-pronged approach that involves potent antioxidant, antiviral, and immunomodulatory properties.

Quick Summary

Elderberry boosts the immune system through its bioactive compounds, primarily anthocyanins and flavonoids. It possesses direct antiviral effects, blocking viral entry and replication, while also modulating immune responses by influencing cytokine production. These actions help reduce the severity and duration of viral respiratory illnesses.

Key Points

Antiviral Action: Elderberry's anthocyanins directly block viral glycoproteins, preventing viruses like influenza from entering and infecting host cells.
Immune System Modulation: Compounds in elderberry help regulate the immune system by influencing the production of cytokines.
Reduces Viral Replication: Studies show that elderberry extract can suppress the multiplication of viruses.
Antioxidant Protection: Its high antioxidant content combats cellular damage from oxidative stress, supporting immune cell function.
Anti-inflammatory Effects: The anti-inflammatory properties of elderberry's anthocyanins can help alleviate symptoms associated with inflammatory responses.
Supports Respiratory Health: Clinical research indicates that elderberry can help reduce the length and severity of symptoms from upper respiratory infections like colds and flu.
Must Be Cooked: Raw elderberries and other parts of the plant are toxic; it is essential to consume only cooked or commercially prepared extracts and products.

The Core Components: Elderberry's Bioactive Compounds

The power of elderberry (specifically, Sambucus nigra) for immune health comes from its rich profile of naturally occurring bioactive compounds, including anthocyanins, flavonols, phenolic acids, and lectins. Anthocyanins, responsible for the berries' dark color, are potent antioxidants with anti-inflammatory and antiviral effects. Flavonols like quercetin, rutin, and isorhamnetin also contribute strong antioxidant properties. Phenolic acids provide further antioxidant benefits, and lectins show potential in modulating immune responses.

A Multi-Faceted Antiviral Mechanism

Elderberry actively combats viruses through several mechanisms, interfering with their life cycle.

Blocking Viral Entry

Elderberry compounds, such as certain flavonoids, including anthocyanins, can bind to viral glycoproteins like the hemagglutinin spikes on influenza viruses. This binding prevents the virus from attaching to and entering host cells, effectively blocking the initial stage of infection.

Suppressing Viral Replication

Research indicates elderberry extracts may inhibit viral replication.

Immunomodulatory Effects: Orchestrating the Immune Response

Elderberry also supports the immune system by modulating its response. Research suggests elderberry extract can increase the production of certain inflammatory cytokines, such as IL-6 and TNF-alpha, in immune cells. This may help initiate an early immune response against invading viruses. The effect appears balanced, avoiding overstimulation.

Managing Inflammation

Elderberry's anthocyanins also possess anti-inflammatory properties. These compounds can help regulate inflammation. Some studies show a reduction in inflammatory markers in activated immune cells, which may help alleviate inflammation-related cold and flu symptoms.

How Elderberry Works: Antiviral vs. Immunomodulatory Action


Feature	Direct Antiviral Action	Immunomodulatory Effects
Mechanism	Inhibits viral entry and replication by blocking viral surface proteins.	Regulates the immune system's response by influencing cytokine production.
Key Compounds	Anthocyanins, flavonoids.	Anthocyanins, polysaccharides, lectins.
Timing	Effective in the early stages of infection, preventing it from taking hold.	A systemic effect that can support the immune system throughout the illness.
Symptom Impact	Reduces the overall duration and severity of the illness.	Helps manage inflammation-related symptoms like aches and fever.
Action	Directly attacks the virus itself.	Enhances the body's natural defense system.

The Supporting Cast: Antioxidants and Overall Health

Elderberry's high concentration of antioxidants, including vitamin C, helps protect cells from damage caused by oxidative stress. By neutralizing free radicals, these antioxidants support the health of immune cells and other tissues, allowing the immune system to function more effectively against infections.

Clinical Evidence and Safety

Clinical studies have investigated elderberry's effectiveness against respiratory illnesses. A meta-analysis indicated that elderberry supplementation can significantly reduce upper respiratory symptoms associated with colds and flu. Another study found reduced duration and severity of cold symptoms in airline passengers who took elderberry.

Raw or unripe elderberries, leaves, bark, and seeds contain toxic compounds. These harmful substances are eliminated during cooking and processing for safe, commercially available elderberry products.

Conclusion

So, why does elderberry boost the immune system? Its efficacy is due to a sophisticated interplay of bioactive compounds, particularly anthocyanins and flavonoids. These components directly combat viruses by blocking their entry and replication while also modulating the immune system through cytokine regulation. Combined with antioxidant and anti-inflammatory properties, elderberry provides comprehensive immune support, potentially reducing the severity and duration of seasonal illnesses. Choosing products from reputable manufacturers is essential for safety and effectiveness.

Reputable Resource

For more in-depth information, visit the {Link: NIH website https://pmc.ncbi.nlm.nih.gov/articles/PMC8026097/}.

Frequently Asked Questions

The most significant compounds are anthocyanins and flavonoids. Anthocyanins, which give the berries their dark color, have direct antiviral properties, while flavonoids like quercetin contribute powerful antioxidant effects.

Elderberry does both. It has a direct antiviral action by inhibiting viral entry into cells, and it also modulates the immune system by influencing cytokine production to enhance the body's natural defense mechanisms.

No, you should never eat raw or unripe elderberries. They contain cyanogenic glycosides, which can be toxic and cause nausea, vomiting, and diarrhea. Only cooked or processed elderberry products, like syrups and extracts, are safe for consumption.

Some clinical studies suggest that elderberry may reduce the duration of flu symptoms by several days when taken within 48 hours of onset. However, individual results may vary, and more research is needed to confirm efficacy.

While some older studies raised concerns about elderberry overstimulating the immune system, more recent systematic reviews have not found evidence to support this claim in healthy individuals. Elderberry appears to have a more modulatory, rather than excessively stimulatory, effect.

Elderberry extract is a concentrated form derived from the berries, often standardized for anthocyanin content. Syrups are typically made from the extract, often with added sweeteners and other ingredients. The concentration of active compounds can vary, so it is important to check the label.

Some people take elderberry as a preventative supplement, but it is most often used to help reduce the severity and duration of symptoms once a cold or flu has started. Its effectiveness for long-term prevention is not as well-established as its use for treating symptoms.