Lactoferrin: What It Is, Benefits Research and Side Effects

Lactoferrin is an iron-binding protein found naturally in milk, tears and saliva, and the lactoferrin sold in supplements and added to some infant formulas is almost always bovine lactoferrin isolated from cow’s milk. Research has focused on its role in immune defense and iron handling. The strongest trials were done in premature babies in hospital care, with mixed results, while studies in children and adults are small. Below is what lactoferrin is, what the research on lactoferrin benefits actually shows, its regulatory status, and lactoferrin side effects and label checks.

Peptide Labs does not sell lactoferrin supplements. This article is general information, not medical advice.

What is lactoferrin?

Lactoferrin, also called lactotransferrin, belongs to the transferrin family of proteins, which bind iron tightly and reversibly. It is a glycoprotein, meaning a protein with sugar chains attached, of roughly 690 amino acids. Its structure has two halves, called lobes, and each lobe can hold one iron atom. Scientists first isolated it from both human and cow’s milk in 1960. Those details come from the scientific background in an FDA GRAS notice for bovine lactoferrin (GRN 669).

In the body, lactoferrin is found in most secretions, including milk, tears and saliva, and it is considered part of the innate immune system. It is one of the main whey proteins in human milk and a normal component of colostrum, the first milk. In cow’s milk it is a minor protein, about 1.4% of the whey protein according to the same FDA file. That is why lactoferrin appears in discussions of colostrum and of whey products, although ordinary whey powders are not standardized for it.

How bovine lactoferrin is made

Commercial bovine lactoferrin is isolated from skimmed milk or cheese whey using ion exchange and ultrafiltration, then freeze-dried or spray-dried, according to the European Commission definition quoted in the FDA file. A 2019 review in Critical Reviews in Food Science and Nutrition (Wang and colleagues) notes that lactoferrin is added to supplements, infant formula, cosmetics and even toothpaste, and that it is sensitive to heat, which can unfold the protein and change how it behaves. Human and bovine lactoferrin are similar but not identical proteins.

Lactoferrin benefits: what the research shows

Most of the excitement about lactoferrin benefits comes from laboratory studies showing it can bind iron that microbes need and interact with immune cells. Human trials are the real test, and they tell a more cautious story. The table summarizes the main areas studied.

Premature babies: the most studied group

A 2020 Cochrane review (Pammi and Suresh) pooled 12 randomized trials with 5,425 preterm infants and found that lactoferrin added to feeds reduced late-onset sepsis, with low-certainty evidence, but did not change rates of necrotizing enterocolitis or death. The authors warned that publication bias and small, weaker studies may inflate the effect. Two large, well-run trials point the same cautious way. The UK ELFIN trial of 2,203 very preterm infants found late-onset infection in 28.9% of the lactoferrin group and 30.7% of the control group, a difference too small to rule out chance, with no differences in other outcomes. The LIFT trial in Australia and New Zealand, with 1,542 very low birthweight infants, found death or major illness in 21% versus 22%. These studies took place in neonatal intensive care units with specific products; they are not a reason for parents to add supplements to a baby’s feeds. Questions about infant formula belong with your pediatrician.

Colds and immune function in children and adults

A 2022 systematic review in Advances in Nutrition (Berthon and colleagues) examined 25 studies. Respiratory infections were less frequent with lactoferrin in infants and children, mostly from fortified formulas, but not in adults. In adults, one inflammation marker (IL-6) dropped while another (C-reactive protein) did not, and the authors described clinical studies as limited. A smaller 2021 meta-analysis (Ali and colleagues) pooled six trials with 1,194 participants and found lower odds of respiratory infection, but two included trials had a high risk of bias and the authors called for a large, well-designed trial. In short, the adult case for a lactoferrin supplement for immunity is unproven.

Iron and pregnancy

Because lactoferrin binds iron, it has been compared with standard iron pills. A 2017 meta-analysis (Abu Hashim and colleagues) combined four trials with 600 pregnant women who had iron deficiency anemia. Hemoglobin rose slightly more with lactoferrin overall, there was no significant difference in mild anemia, and lactoferrin caused fewer stomach side effects than ferrous sulfate. The trials were small. Low iron in pregnancy needs testing and follow-up with your OB-GYN, not self-selected supplements; our guides to iron pill side effects and iron-rich eating cover the basics.

Is lactoferrin safe? FDA status

Bovine lactoferrin has a long food history because it is naturally present in cow’s milk, and lactoferrin-fortified infant formulas have been sold in Japan since 1986. In the United States, FDA responded to Morinaga’s GRAS notices on February 18, 2014 with no questions about bovine lactoferrin in term infant formula (GRN 465) and in foods such as yogurt, powdered milk, frozen desserts and chewing gum (GRN 464). It sent a similar no-questions letter to Synlait in March 2017 for infant and toddler formula (GRN 669). Earlier notices covered lactoferrin as an antimicrobial in meat packing. A GRAS response applies to the stated food uses; FDA does not approve dietary supplements for safety or effectiveness before they are sold.

Lactoferrin side effects and who should be careful

Trials have generally reported lactoferrin as well tolerated; the 2020 Cochrane review found no adverse effects in preterm infants, and the pregnancy trials reported fewer stomach complaints than iron pills. Still, a few cautions apply:

• Cow’s milk allergy: bovine lactoferrin is a milk protein. Anyone with a milk allergy should ask their allergist before using it.
• Lactose: isolated lactoferrin is mostly protein, but blends may include milk powders. Check the label if lactose bothers you; our lactase guide explains lactose intolerance.
• Pregnancy, breastfeeding and children: ask your clinician before using any supplement.
• Medical conditions: lactoferrin is not a substitute for care of infections or anemia; see a clinician for symptoms or abnormal blood tests.

How to read a lactoferrin supplement label

A lactoferrin supplement label should state the source (bovine milk), the amount of lactoferrin per serving, and the purity of the ingredient where the brand provides it. Look at the other ingredients for milk powders, colostrum or added iron, and favor brands with independent quality seals, as our guide to third-party tested supplements explains. Be wary of labels that promise immune protection or iron repair; those are claims the evidence does not support for healthy adults. If you are weighing organ-based products for iron, our sibling guide to beef liver supplements covers a very different option with its own cautions.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or breastfeeding, or have a food allergy or a chronic condition. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Last reviewed October 2026.

Related guides: Colostrum: Bovine Colostrum Benefits, Evidence and Who Should Skip It, Foods High in Iron: USDA List, Heme vs Non-Heme Iron and Absorption, Whey Protein: Isolate vs Concentrate, Benefits and Side Effects.