Lactoferrin for Colds and Flu: What the Research Shows

The clearest evidence is in children. A 25-study review found lactoferrin reduced respiratory tract infection incidence in infants and children (odds ratio 0.78), while the pooled adult estimate was neutral. Adult research has expanded considerably since that review closed, and the newer trials are more encouraging.

This article summarises published research and is not medical advice. Lactoferrin is a dietary supplement, not a treatment for any infection.

Where lactoferrin sits in respiratory defence

Lactoferrin coats the mucosal surfaces of the airways, which is exactly where respiratory viruses arrive first. It is also stored in neutrophils, the first white blood cells to reach an infection site. That positioning is why researchers looked here at all.

What the pooled human data found

The 2022 systematic review and meta-analysis in Advances in Nutrition covered 25 studies, 19 of them randomised controlled trials:

• Infants and children: respiratory tract infection incidence reduced, odds ratio 0.78 (95% CI 0.61 to 0.98).
• Adults: pooled estimate neutral, odds ratio 1.00 (95% CI 0.76 to 1.32), which the authors flagged as reflecting how few adult trials existed at the time.
• Inflammation: interleukin-6 reduced by a mean of 24.9 pg/mL.
• The authors identified formulas containing 35 to 833 mg per day as the range associated with reduced infection incidence in infants and children.

The newer adult trials

Research published since that review closed its search in December 2020:

• A randomised, double-blind, placebo-controlled trial in Nutrients examined 200 mg per day over 12 weeks for maintenance of respiratory and systemic physical condition in healthy adults.
• A 2026 randomised controlled trial in healthy older adults compared 600 mg and 200 mg per day against placebo over four weeks, reporting reduced systemic inflammation, enhanced antiviral responses and changes in immune cell profiles.
• A 2026 randomised, double-blind, placebo-controlled trial in children aged 0 to 6 found lactoferrin combined with Bifidobacterium animalis subsp. lactis BB-12 over three months improved respiratory tract infection outcomes and modulated gut microbiome function.

What the laboratory work adds

In cell culture, lactoferrin shows broad-spectrum antiviral activity against several common cold coronaviruses, working by binding heparan sulfate proteoglycans on the cell surface. Many viruses anchor to those sites before reaching their specific receptor, so occupying the docking point blocks an early step. Bovine lactoferrin was more potent than human lactoferrin in these assays.

These are laboratory findings. They explain a mechanism, they do not demonstrate a clinical outcome in people.

An honest summary

• In children, pooled trial data support a reduction in respiratory infection incidence.
• In adults, the older pooled data were neutral, newer trials are more promising, and the next synthesis should be considerably more informative.
• Across both, the reduction in inflammatory markers is the most consistent finding.
• Trials reporting effects generally ran 4 to 12 weeks of daily use, so this is about steady intake through a season rather than something to start when you already feel unwell.

Full detail, including every trial's dose and population, is in our immune function research summary.

Related reading

• Lactoferrin and the immune system: how it works
• How much lactoferrin to take
• Lactoferrin for immune support

This information summarises published research and is provided for education. It is not medical advice and not a claim about the effects of any Lactoferrin Co. product. Contains milk. Consult a qualified healthcare professional before starting any supplement.