Elderberry: Does It Really Shorten Colds and Flu?

Every winter, the same scenario repeats: a scratchy throat, a stuffy nose, and a desperate search for something to shorten the suffering. One name that comes up again and again is elderberry. This is one of the few herbal supplements in the immune field that has behind it not only centuries of folk tradition, but also three controlled clinical studies showing a measurable effect.

But precisely because of its immense popularity, many exaggerations have accumulated around elderberry. Supplement companies present it as a kind of natural antibiotic, and social media posts promise it completely prevents the flu. The research reality is more moderate, but still interesting. In this article, we will separate what the research actually shows from what supplement marketing tells you, and explain why our classification for elderberry is 🟡 and not 🟢.

What is Elderberry?

Black elderberry (Sambucus nigra) is a shrub that grows in Europe, West Asia, and North Africa. The relevant parts for supplements are the small purple-black berries, and sometimes also the flowers. Here are the main points:

• Rich in anthocyanins, purple pigments from the flavonoid family, the same substances that give the fruit its color and are powerful antioxidants.
• Contains vitamin C, vitamin A, potassium, and a high amount of polyphenols that affect immune system cells.
• Consumed mainly as an extract, syrup, or standardized capsules, and not as fresh fruit, for an important reason we will get to later.
• Used traditionally to treat colds, flu, and upper respiratory tract infections for centuries in Europe.

Elderberry is not a vitamin you are deficient in, so it is fundamentally different from a supplement like vitamin D. It is taken specifically during illness, or seasonally during periods of increased exposure, and not as a daily lifelong supplement.

The Connection to the Immune System: A Possible Mechanism

Laboratories that studied elderberry have identified several biological pathways that could explain the effect. It is important to clarify: a large part of the mechanism is based on test-tube and animal studies, and has not been fully proven in humans.

• Blocking virus entry into cells: Anthocyanins from elderberry bind in test-tube studies to the hemagglutinin protein on the influenza virus envelope, the protein the virus uses to attach to and infect a cell.
• Effect on cytokines: Studies have shown that elderberry extract increases the production of certain cytokines, signaling molecules of the immune system, which may accelerate the immune response.
• Antioxidant activity: Oxidative stress increases during a viral infection, and the polyphenols in elderberry help neutralize free radicals.
• Anti-inflammatory effect: Some polyphenols balance an excessive inflammatory response, which may alleviate symptoms like sore throat and congestion.

The combination of blocking virus entry along with boosting the immune response is the theoretical explanation for why elderberry shortens the duration of illness rather than preventing it entirely. This also explains why it is more effective when started early, in the first hours of symptoms.

Current Evidence

Study 1: Air Travelers from 2016 (Tiralongo)

The largest controlled study in the field was published in the journal Nutrients in 2016 by a group of researchers from Griffith University in Australia. 312 passengers in economy class on long-haul flights from Australia overseas were randomly divided into an elderberry or placebo group, in a double-blind trial. The passengers took a standardized elderberry extract before and during the flight.

The results: In the elderberry group, there were 12 cold events compared to 17 in the placebo group, and the average cold duration was shorter by about 2 days, along with a reduction in symptom severity. It is important to note that the difference in the number of colds did not reach statistical significance, but the shortening of illness duration was significant. Side effects were rare and not attributed to elderberry.

Study 2: Flu Patients in Norway from 2004 (Zakay-Rones)

An Israeli-Norwegian study published in the Journal of International Medical Research examined 60 patients aged 18 to 54 who had flu symptoms for less than 48 hours. They received 15 milliliters of elderberry syrup or placebo, 4 times a day for 5 days, during the 1999-2000 flu season.

The notable result: In the elderberry group, symptoms were relieved on average 4 days earlier than in the placebo group, and the use of rescue medications (like pain relievers and decongestants) was significantly lower. This is one of the most impressive numbers in the literature, but it should be remembered that it is based on a small sample of only 60 people.

Study 3: Meta-analysis from 2019 (Hawkins)

In 2019, a meta-analysis was published in Complementary Therapies in Medicine that pooled the existing evidence. Out of 137 articles, only 4 controlled studies met the criteria, with a total of 180 participants, 89 in the elderberry group and 91 in the control group.

The statistical analysis revealed a large effect size of 1.717, meaning elderberry consistently shortened the duration of upper respiratory tract symptoms. Interestingly, the flu vaccine did not significantly change the effect. The authors presented elderberry as a possible alternative to the overuse of antibiotics in cases of routine viral infections.

What About Prevention, Not Just Treatment?

Here we need to be precise. The evidence for elderberry is stronger for shortening an existing illness than for preventing it. In the air traveler study, the number of colds was indeed lower in the elderberry group, but the difference was not statistically significant. That is, the strong evidence is that if you are already infected, elderberry may shorten the suffering, but there is no clear proof it will prevent you from getting infected in the first place.

This is why professionals recommend using it at the onset of symptoms and not as a daily regular shield. During transitional seasons, on long flights, or when family members are sick around you, it makes sense to start elderberry specifically.

Should You Start Taking Elderberry?

Despite the positive evidence, there are several important reservations that lead us to a 🟡 classification and not 🟢:

• Critical toxicity warning: Raw, semi-ripe, or uncooked elderberries, as well as the leaves, bark, and seeds, contain cyanogenic glycosides that can cause nausea, vomiting, and diarrhea. You must use only processed commercial extracts and syrups, and never eat the fresh raw fruit.
• Small sample sizes: The studies are impressive but small, with 60 to 312 participants. These are not the large trials from which solid medical recommendations are built.
• Industry funding: Some of the studies were funded by manufacturers of elderberry extracts, which requires caution in interpretation.
• Lack of standardization: The concentration of active ingredients varies greatly between products. Two bottles of elderberry can contain completely different amounts of anthocyanins.

Who should be especially cautious: pregnant and breastfeeding women, people with autoimmune diseases (due to the stimulating effect on the immune system), and those taking immunosuppressive medications. In all these cases, it is advisable to consult a doctor before use.

What to Take Away from the Research?

1. Use only processed extract. Buy syrup, capsules, or a standardized extract from a reliable brand. Never eat raw elderberries you picked yourself; they are toxic.
2. Start early. The strongest effect in the studies was achieved when elderberry was started within the first 48 hours of symptoms. The later you start, the smaller the benefit.
3. Use seasonally, not lifelong. Elderberry is a supplement for times of illness or periods of exposure (flights, winter, exposure to sick people), not a daily regular supplement.
4. Follow the dosage on the product. There is no single universal dosage; the dosage depends on the product's concentration. In studies, about 15 milliliters of syrup was used up to 4 times a day during illness.
5. Don't neglect the basics. Elderberry does not replace sleep, adequate vitamin D, good nutrition, and hand washing. It is an addition, not a substitute.

If you want to check which supplements are suitable for your health goals in a personalized way, try our personal supplement selector. For those looking for a quality, properly processed elderberry product, you can purchase elderberry on iHerb.

The Broader Perspective

Elderberry is an excellent example of a supplement for which science tells a moderate but true story. It is not a miracle cure and does not prevent disease, but there is reasonable evidence that it shortens the duration of colds and flu by a few days when started early. At a low cost, with a good safety profile (as long as you use a processed extract), and a research base three times more solid than most immune supplements on the market, it deserves a place in the seasonal medicine cabinet.

But our 🟡 classification reminds us of the big truth: no single supplement beats a healthy lifestyle routine. A person who sleeps 7 hours, exercises, eats well, and is vaccinated copes with viruses better than a person who relies on a bottle of elderberry. Elderberry is a nice aid in the right season, not the sole line of defense. And as always in this field: basics first, supplements second.

References:
Tiralongo E, Wee SS, Lea RA. Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers. Nutrients. 2016;8(4):182.
Zakay-Rones Z, et al. Randomized Study of the Efficacy and Safety of Oral Elderberry Extract in the Treatment of Influenza A and B. J Int Med Res. 2004;32(2):132-140.
Hawkins J, et al. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis. Complement Ther Med. 2019;42:361-365.