Lactoferrin

What it is

Lactoferrin is a glycoprotein, that is, a protein with sugar chains, found in tears, saliva, mucosal secretions and above all in milk. In breast milk it is the second most abundant whey protein. A systematic review of 52 studies with 2,724 women found an average of 4.91 g per liter in early milk and 2.10 g per liter in mature milk.

Dietary supplements and infant formula use bovine lactoferrin from cow’s milk. According to the EU Union list, it is an iron-binding glycoprotein of about 77 kDa with 689 amino acids, obtained from skimmed milk or cheese whey. It is an almost odorless, light pink powder. Since 2012 it has been authorized in the EU as a novel food and is added, among other things, to infant formula to bring it closer to breast milk.

How it is supposed to work

The basic idea is simple: lactoferrin binds iron very tightly. Bacteria need iron to grow, and what lactoferrin holds on to is not available to them. In addition, there are direct effects on bacterial membranes and viruses, which are well described in the laboratory, as well as a dampening effect on inflammatory messengers.

In humans, part of this is measurable. In a meta-analysis, the inflammatory messenger IL-6 fell in adults, but CRP and the activity of natural killer cells did not change. For iron, researchers suspect that lactoferrin works less through better absorption than through less inflammation, which otherwise slows down iron metabolism. This fits a meta-analysis in which measured iron absorption under lactoferrin was even somewhat lower than under ferrous sulfate, by 2.08 percentage points, while serum iron, ferritin and the inflammatory marker IL-6 were more favorable.

One open point is digestion. Lactoferrin is a protein and is partly broken down in the gastrointestinal tract. A systematic review on the fate of orally ingested lactoferrin describes it as sensitive to digestion; the cleavage peptide lactoferricin was not detectable in digestion samples. How much arrives intact and where it acts is therefore not fully resolved.

What users are looking for

In the biohacking scene, lactoferrin is taken mainly during the cold season, as a supplement in iron deficiency when iron tablets irritate the stomach, and as a friend of the gut. Many report that they tolerate it better than iron products. This is consistent with the studies on tolerability, but as a user report it is not evidence of efficacy.

What the studies show

Cochrane review in preterm infants

The 2020 Cochrane analysis summarizes 12 randomized trials with 5,425 preterm infants. Lactoferrin in the feed lowered late-onset infections with a relative risk of 0.82; the certainty of evidence is considered low. It had no influence on the dreaded bowel disease NEC or on mortality. Together with probiotics, the effect was stronger in 3 smaller studies. Side effects were not reported.

The ELFIN trial

The largest single trial ran in 37 British hospitals with 2,203 very preterm infants. They received bovine lactoferrin or sugar as placebo daily, double-blind. A late-onset infection occurred in 29 percent under lactoferrin and in 31 percent under placebo, a relative risk of 0.95. The primary endpoint was missed; the authors advise against routine administration.

Lactoferrin versus ferrous sulfate in Bangladesh

The newest and so far largest iron study, in 2026, compared 200 mg or 400 mg of lactoferrin with 60 mg of iron as ferrous sulfate over 12 weeks in 555 non-pregnant women with iron deficiency anemia. Hemoglobin changed by -0.2 and 0.0 g/dl under lactoferrin and by 1.1 g/dl under ferrous sulfate. Lactoferrin was thus clearly inferior; side effects did not differ.

Where the data stop

In adults, protection against infections is not established. The positive overall figure from the meta-analyses comes predominantly from studies in children; in adults the odds ratio was 1.00. For iron, the data contradict each other. Older meta-analyses see lactoferrin ahead, but are extremely heterogeneous, one of them with an I² of 95.8 percent. The large 2026 study found the opposite. In children, lactoferrin in addition to iron did not raise hemoglobin; only ferritin rose slightly, by 3.52 µg/L. In preterm infants, the Cochrane analysis stands against the largest single trial. During the pandemic, lactoferrin was widely discussed; a double-blind study with 72 people with long COVID found no benefit for fatigue or other symptoms with 1,200 mg per day over 6 weeks. On longevity, skin or weight there are no reliable human data.

Status, approval and legal

Bovine lactoferrin has been authorized in the EU as a novel food since 2012 and is now on the Union list. It is authorized for infant formula at up to 100 mg per 100 ml, for dairy products, beverages and confectionery, and for foods for special medical purposes at up to 3 g per day. Dietary supplements are not listed as a separate category in the Union list. In German retail, lactoferrin is therefore declared partly as a dietary food for special medical purposes and partly as a dietary supplement; an official clarification on this could not be found for this page. It is not a medicine, there is no authorized health claim, and it is not on the doping list. The studies mostly used 200 to 400 mg per day in adults, and 1,200 mg per day in the long COVID study.

Safety

Lactoferrin is a component of the normal diet, in breast milk and in infant formula. In 2012, EFSA assessed bovine lactoferrin as safe at the amounts applied for; in adults this corresponded to an average of about 1.4 g per day. In a 13-week study in rats, even the highest dose of 2,000 mg per kilogram of body weight showed no side effects. In the randomized trials, side effects were as frequent as in the control groups; compared with ferrous sulfate, fewer gastrointestinal complaints occurred. Because it is obtained from cow’s milk, it is unsuitable for people with a milk protein allergy. Anyone with iron deficiency anemia should have it assessed by a physician and should not see lactoferrin as the sole substitute for iron therapy.

Sources

• Ali et al., Clin Nutr ESPEN 2021 – meta-analysis, respiratory infections
• Berthon et al., Adv Nutr 2022 – inflammation, immune function, respiratory infections
• Mayorga et al., Biochem Cell Biol 2025 – infections in children
• Pammi and Suresh, Cochrane Database Syst Rev 2020 – preterm infants
• ELFIN trial investigators, Lancet 2019 – RCT with 2,203 preterm infants
• Abu Hashim et al., Eur J Obstet Gynecol Reprod Biol 2017 – anemia in pregnancy
• Huda et al., J Nutr 2026 – lactoferrin versus ferrous sulfate, 555 women
• Sachdeva and Nagpal, Aliment Pharmacol Ther 2009 – Helicobacter pylori
• EFSA NDA Panel, EFSA Journal 2012 – safety of bovine lactoferrin
• Implementing Regulation (EU) 2017/2470 – Union list of novel foods