Lactoferrin, without the runaround.

What lactoferrin is, briefly

Lactoferrin is a protein. Your body makes it, and so do cows, which is where supplements come from. It turns up in milk, especially the first milk after birth, and in tears, saliva and the fluid lining your gut. It is also packed inside a type of white blood cell called a neutrophil.

Milk is the only place it occurs in food, and how much reaches you depends on how hot that milk got. Flash pasteurizing leaves most of it and UHT leaves none a test can find, so whether pasteurization removes lactoferrin from milk comes down to which carton you picked up. The amounts in each food high in lactoferrin are measured and short of a supplement dose.

Its main trick is grabbing iron and holding onto it very tightly. That matters in two completely different ways, which is why this site has two halves.

Because it lives inside white blood cells, lactoferrin shows up in your stool when those cells travel into your gut wall, which is what happens during inflammation. That is what a stool test is looking for, and a small amount being there is ordinary, so the question of whether lactoferrin in stool is bad turns on how much and on what else is going on. And because holding iron away from bacteria slows some of them down, lactoferrin has been sold as a supplement for decades, with results that range from reasonably supported to not supported at all. The full list of what lactoferrin is used for runs wider than a bottle suggests, and takes in infant formula and a spray for beef carcasses.

What this site does

It answers the question at the top of the page, in the first paragraph, in plain words. Then it explains. Every health claim names the research it comes from, with a link you can follow, and where a study found nothing that gets said just as plainly. The sources for this page are listed at the bottom, and every page here has the same list.

Nothing is sold here. There are no affiliate links, so there is no reason for this site to talk you into anything.