Benefits
Upper respiratory symptom duration and severity in controlled trials
In two small placebo-controlled trials of a branded syrup extract, symptoms in people with flu-like illness eased several days sooner. A larger independent placebo-controlled trial in emergency room patients with laboratory-confirmed flu found no benefit on symptom duration or severity. An independent review rated the evidence low or very low certainty and noted that most trials had a company sponsor.
Upper respiratory symptoms in long-haul air travelers
In a placebo-controlled trial of 312 air travelers funded by the extract maker, the number of people who developed a cold did not differ between groups, but the placebo group logged about twice as many cold episode days and higher symptom scores. Upper respiratory quality of life scores did not differ significantly between groups.
Antiviral activity in laboratory studies
In cell culture, elderberry extracts reduced hemagglutination and replication of several human influenza A and B strains, flavonoids from an extract bound H1N1 virions and blocked cell entry, and a branded liquid extract inhibited an H5N1-type isolate. The binding study was done at HerbalScience Group, a private company, and the H5N1 study tested a branded extract. This is laboratory activity only, not evidence of an effect in people.
Cytokine effects in laboratory and ex vivo studies
When human monocytes were exposed to branded elderberry preparations in the laboratory, production of inflammatory cytokines rose. An independent review found three small studies, with 51 people in total, that measured cytokines after people took elderberry: some markers fell, others were unchanged, and there was no evidence of immune overstimulation.
Cardiometabolic and antioxidant markers in placebo-controlled trials
In a 12-week placebo-controlled trial in 52 postmenopausal women taking 500 mg a day of elderberry anthocyanins, cardiovascular risk biomarkers did not change significantly. In a smaller 2-week trial of spray-dried elderberry capsules, cholesterol changed only slightly and not significantly, and LDL resistance to oxidation did not change.
Mechanism of action
Viral binding and hemagglutination in cell culture
In laboratory studies, a standardized elderberry extract reduced influenza hemagglutination in cell culture, and two flavonoids identified in an elderberry extract bound H1N1 virions and blocked their entry into host cells. The binding work was done at HerbalScience Group, a private company. No study cited on this page measured viral entry or infectivity in people.
Cytokine induction
When human monocytes were incubated with branded elderberry preparations in the laboratory, production of TNF-α, IL-1β, IL-6 and IL-8 rose. Whether this occurs at supplement doses in people is unsettled: in an independent review, small studies measuring cytokines after ingestion found reductions or no change, and no evidence of immune overstimulation. This is the basis for the autoimmune caution under side effects.
Clinical trials
Randomized, double-blind, placebo-controlled trial of Sambucol, a standardized elderberry extract, in a kibbutz during a 1993 outbreak; the same paper reports the cell culture antiviral work. An independent review found no sponsor reported, counted 27 participants analyzed, and rated the risk of bias high for incomplete outcome data (Zakay-Rones et al. 1995, J Altern Complement Med)
Residents of an agricultural community (kibbutz) who fell ill during an influenza B outbreak; 27 analyzed according to an independent review.
Symptoms including fever improved within 2 days in 93.3% of the elderberry group, while 91.7% of the control group improved only within 6 days (p < 0.001). Complete cure took 2 to 3 days in nearly 90% of the elderberry group and at least 6 days with placebo (p < 0.001). Convalescent antibody titers to influenza B were higher with elderberry.
Randomized, double-blind, placebo-controlled trial of Sambucol syrup, 15 mL four times daily for 5 days, in Norway during the 1999 to 2000 season. An independent review lists Razei Bar of Jerusalem as sponsor, and the authors called for a larger confirmatory study (Zakay-Rones et al. 2004, J Int Med Res)
60 adults aged 18 to 54 with influenza-like symptoms for 48 hours or less.
Symptoms were relieved on average 4 days earlier, and rescue medication use was significantly lower, with elderberry than with placebo.
Randomized, double-blind, placebo-controlled trial of a membrane-filtered Sambucus nigra extract (BerryPharma brand), 300 mg capsules, 2 a day from 10 days before travel and 3 a day from 1 day before departure until 4 to 5 days after arrival. Funded by the extract maker Iprona AG, which supplied the capsules and was partly involved in study design (Tiralongo et al. 2016, Nutrients)
312 economy class passengers flying from Australia to overseas destinations.
Cold episodes did not differ significantly between groups (12 vs 17, p = 0.4). The primary outcome, total cold episode days, was lower with elderberry (57 vs 117, p = 0.02), and the average symptom score over those days was lower (247 vs 583, p = 0.05). Upper respiratory quality of life scores (WURSS-21) did not differ significantly.
Investigator-initiated, double-blind, randomized, placebo-controlled trial run under an FDA Investigational New Drug application in three emergency rooms, 2018 to 2019; 15 mL (5.7 g) extract four times daily for 5 days (twice daily for ages 5 to 12), and patients could also choose oseltamivir. Small sample, but powered above 0.90 to detect a 2-day benefit (Macknin et al. 2020, J Gen Intern Med)
87 patients over age 4 with under 48 hours of at least 2 moderate symptoms and a positive PCR flu test.
No difference from placebo. Days until all symptoms were none or mild averaged 5.3 with elderberry and 4.9 with placebo (p = 0.57), and days to complete resolution averaged 8.6 and 8.7 (p = 0.87). In a post hoc analysis, outcomes with elderberry alone were 2 days worse than with placebo alone.
Parallel randomized, placebo-controlled trial of 500 mg a day of anthocyanins as cyanidin glycosides from elderberry (2 capsules twice daily) for 12 weeks; a null result for its main outcomes (Curtis et al. 2009, J Nutr)
52 healthy postmenopausal women (26 per group).
After 12 weeks, none of the measured disease-risk blood markers changed significantly compared with placebo, and routine organ-function blood tests stayed within clinically acceptable ranges. Anthocyanins did not build up in plasma.
Randomized, double-blind, placebo-controlled trial of capsules with 400 mg spray-dried elderberry powder (10% anthocyanins) three times daily for 2 weeks, with a 14-person subgroup continuing a third week; a separate 6-person single-dose test used 50 mL juice with a high-fat breakfast. A null result for its main outcomes (Murkovic et al. 2004, Eur J Clin Nutr)
34 healthy young volunteers in the placebo-controlled part.
Blood fat measures changed only slightly and not significantly versus placebo, and the resistance of low-density lipoprotein particles to copper-induced breakdown did not change over 3 weeks. In the single-dose test, the rise in blood fats after the meal did not differ significantly with and without the juice.