What the science really says about colostrum supplements
Marketed as “liquid gold” for gut and immune health, colostrum plays a critical role in infancy—but research suggests adults may see far fewer benefits.
Often called liquid gold for its rich, yellow hue, colostrum is the nutrient-dense fluid mammals produce in the first days after giving birth. In recent years, bovine colostrum—derived from cows—has been increasingly marketed as a dietary supplement with claims that it can reduce the risk of infection and strengthen the gut lining.
However, many scientists are skeptical that a substance intended for newborn calves can actually benefit adult humans. So what does the evidence actually show—and does colostrum offer anything meaningful once the human immune system is fully developed? Here’s what experts have to say.
What is colostrum?
Colostrum is the nutrient-rich fluid produced by the mammary glands in the first 24 to 72 hours after a mammal gives birth, before mature milk comes in. Bovine colostrum is the most common type used in dietary supplements, and has a similar nutritional composition to the human variety, says Federica Amati, nutrition lead at Imperial College Faculty of Medicine and head nutritionist at personalized nutrition company Zoe. “It’s got a very high total protein concentration, but casein is the predominant protein for bovine colostrum, whereas in human colostrum, it’s more whey proteins.”
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Both are high in immunoglobulins (another word for antibodies, which fight germs) and growth factors, which stimulate growth hormone production. “Bovine colostrum has a lot more growth factors, because baby cows are born quite small and quickly become very big,” Amati says.
It also contains a higher concentration of fat and minerals, including calcium, phosphorus, magnesium, iron, and zinc. Human colostrum contains greater levels of lactoferrin, a protein necessary for “maintaining good iron status in babies and reducing the efficacy of viral infections. That’s why a lot of people think colostrum is really good for adults and their immune system.”
How does colostrum benefit newborns?
“Midwives often term colostrum ‘liquid gold’ because it essentially provides borrowed immunity for the newborn from the mother,” says Aliza Marogy, registered nutritionist and founder of clinical supplement brand Inessa.
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At birth, an infant’s gut microbiome is largely underdeveloped. Ingesting colostrum is one of the ways (alongside the birth process, skin contact, and the environment around them) the microbiome becomes populated with healthy bacteria, which, in turn, helps build a strong immune system.
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“Colostrum is a really important part of protecting the baby from infection in the first days of life, because they have no innate immune system. They rely on colostrum to provide the antibodies that would fight off germs,” Amati says. “If babies can’t have colostrum, it increases their risk of upper respiratory tract infections and something called necrotizing enterocolitis,” a rare but serious condition in which portions of the intestine become inflamed and damaged. The disorder primarily affects premature infants and is exceedingly uncommon in adults.
Are colostrum supplements effective for adults?
While colostrum is packed with nutrients and incredibly useful for newborns, there’s very little evidence that capsule or liquid supplements are effective for human adults, and it could actually be harmful in some cases.
“There was one study [from 2015] on very malnourished children in a low-income setting which showed it helped a little bit, but that does not translate to an American adult,” says Amati. A 2021 review found that colostrum showed ‘interesting effects’ in preventing respiratory infections in athletes, and a 2024 review found ‘limited evidence’ for alleviating gastrointestinal (GI) symptoms. Still, there is “not enough high-quality evidence to recommend colostrum supplementation to support immunity or gut health in adults.”
The main reason colostrum supplements don’t work is that the human gut microbiome is fully established by around age three. “If you give an infant gut colostrum, it will respond, because the biome and immune system are still forming,” Amati says. “After the age of three or four, you can influence which microbes flourish on a day-to-day basis with what you feed your gut, or the probiotics you take, but the deeper niches that you have in your gut don’t change that easily–unless you take antibiotics, and then they get destroyed.”
Unlike probiotics, bovine colostrum supplements do not contain live microorganisms. And because they are classified as dietary supplements, they are not evaluated for efficacy or approved by the U.S. Food and Drug Administration before reaching the market. As a result, the concentration of bioactive compounds—such as immunoglobulins—can vary widely between products. “When you actually look at the bioactive compounds that people take them for–in bovine colostrum’s case, immunoglobulins–it’s variable how much is going to be in there,” Amati says.
There are additional risks to consider, Marogy says. “People with a dairy allergy in particular should absolutely avoid it, and those who are immunocompromised shouldn’t really be taking colostrum because we don’t have enough evidence to suggest that it’s safe.” And for people who report feeling better after taking colostrum? “As with any medication or supplement, there may be an element of a placebo effect,” Marogy adds.
“The only positive of bovine colostrum is that it’s bringing attention to the importance of gut health for the immune system,” says Amati, who recommends eating high-fiber and fermented foods that your microbiome can feast on as the best way to improve your gut function and immunity. By comparison, she adds, colostrum supplements amount to little more than “a really expensive milk powder.”
