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Colostrum is the first milk a mammal makes after giving birth, and the colostrum sold as a supplement comes from cows. Bovine colostrum is rich in antibodies, mainly IgG, along with lactoferrin and growth factors that help a newborn calf. In people, the evidence is small: a handful of trials in athletes found less exercise-related gut leakiness and fewer cold-like symptoms, but most studies were tiny, short and at risk of bias, and some were run by researchers with links to colostrum companies. It is a dairy product, so anyone with a milk allergy should avoid it. Here is what is in it, what the research found, and how to read the labels.
Peptide Labs sells products that list colostrum, but this article does not recommend any of them. It is general information, not medical advice.
Key Takeaways
- Bovine colostrum is the milk cows make in the first few days after calving, dried into a powder.
- Its main antibody is IgG; it also contains lactoferrin, growth factors and some lactose.
- Small trials in athletes found less exercise-related gut permeability and fewer respiratory symptom days.
- Pooled studies found little or no change in blood antibody levels or immune cell counts.
- It is a milk product: avoid it with a dairy allergy, and ask a clinician first with a hormone-sensitive cancer.
What is bovine colostrum?
Cows, unlike people, cannot pass antibodies to their calves through the placenta. A newborn calf gets its first antibodies from colostrum, which is why it is so concentrated. According to a 2021 review in Nutrients, IgG makes up roughly 80 to 90% of the immunoglobulins in bovine colostrum, with smaller amounts of IgA, IgM and others. The composition changes fast: several growth factors drop sharply within two to three days of calving.
To make a colostrum supplement, colostrum is frozen on the farm, pasteurized at a central plant, sometimes defatted and stripped of lactose, then spray-dried or freeze-dried into a powder. That powder goes into capsules, chewables, drink mixes and blended formulas. Because quality varies with the herd, timing and processing, IgG content is often used as a marker of quality, which is why some labels say a product is standardized to a percentage of immunoglobulins.
What is in it
| Component | What it is | What to know |
|---|---|---|
| IgG and other immunoglobulins | Antibodies that protect the calf's gut and blood | Main selling point; human benefit not established |
| Lactoferrin | Iron-binding protein | Present, but at about a tenth of the level in human colostrum |
| Growth factors such as IGF-1 | Proteins that support the newborn gut | Large amounts did not raise blood IGF-1 in healthy adults |
| Lactose | Milk sugar | Lower than in regular milk; some powders remove it |
| Milk proteins such as beta-lactoglobulin | Whey and casein proteins | Beta-lactoglobulin is a major cow milk allergen |
Colostrum benefits: what the research shows
Most marketing for colostrum benefits rests on two lines of research, both done mainly in athletes. Neither has produced the large, independent trials needed to call the effects proven.
Gut permeability during hard exercise
Intense exercise in the heat can make the gut lining temporarily leakier, measured by how much of two test sugars ends up in urine. In a 2011 UK crossover study of 12 volunteers, permeability rose 2.5-fold after exercise on placebo, while two weeks of colostrum cut that rise by 80%. A 2016 follow-up by the same group with only eight volunteers found that colostrum or zinc carnosine each reduced the rise by about 70%.
A 2024 meta-analysis of 10 studies in athletes and patients found lower sugar-test ratios after colostrum, but the results varied enormously between studies, and a blood marker of gut injury did not change. The authors said more trials with better quality and consistent products are needed. These are lab measurements over days or weeks, not evidence that colostrum improves digestion or long-term health. The lead author of this research also co-wrote the 2021 review, whose authors disclosed a link to a company that sells colostrum.
Immune markers and colds in athletes
A 2016 meta-analysis pooled five trials with 152 adults in regular training and found 44% fewer days with upper respiratory symptoms over 8 to 12 weeks. However, four of the five trials had a moderate or high risk of bias, and the authors called for one well-designed, adequately powered trial. A 2020 meta-analysis of 10 trials with 239 active adults found that colostrum had little or no effect on blood antibody levels, immune cell counts or saliva antibodies, so how any benefit might work is unclear.
| Claim | What studies tested | Strength of evidence |
|---|---|---|
| Supports the gut lining | Sugar permeability tests around hard exercise, 8 to 12 people per trial | Low; small trials, very mixed results |
| Fewer colds in athletes | 5 trials, 152 people in training | Low; most trials at risk of bias |
| Boosts antibodies | 10 trials, 239 active adults | Little or no effect on blood or saliva antibodies |
| Weight loss or metabolism | No good human trials found | Not supported |
Marketing hype versus evidence
Colostrum has become a popular wellness ingredient, and some sellers go far past the research. The FDA has sent warning letters to colostrum companies over claims about allergies, arthritis, cancer and memory loss. In June 2020, the FDA and the Federal Trade Commission jointly warned Sovereign Laboratories over colostrum products marketed for COVID-19, calling them unapproved new drugs. A dietary supplement cannot legally make disease claims, so any label or ad that does is a red flag.
If you want to see how colostrum compares with other gut-focused ingredients, our guides on improving gut health and the Akkermansia probiotic cover the evidence for diet, fiber and specific strains. L-glutamine, another ingredient often sold for the gut lining, has its own mixed record.
Side effects and who should avoid a colostrum supplement
Colostrum is generally reported as well tolerated in studies, but the trials were small and short. Memorial Sloan Kettering’s integrative medicine service lists these cautions:
- Milk allergy: avoid it. Colostrum is cow’s milk, and its whey proteins include a major milk allergen. One case report describes anaphylaxis in a dairy-sensitive teenager after a colostrum-based cream was applied to a surgical wound.
- Hormone-sensitive cancers: colostrum contains trace amounts of naturally occurring estrogen, so talk with your oncologist first.
- Lactose intolerance: colostrum has less lactose than milk, and some powders remove it, but labels vary.
- Vegan or vegetarian diets: it is an animal product, and many capsules are gelatin.
- Pregnancy, breastfeeding, children and anyone on medicines: safety data are limited; ask a healthcare provider.
Stop using it and get medical help right away for hives, swelling of the lips or throat, or trouble breathing.
Reading colostrum labels
Look for the source (bovine), whether the product is standardized for immunoglobulins or IgG, and an allergen statement for milk. Independent testing matters because colostrum quality varies; our guide to third-party tested supplements explains what seals mean. Two products we carry list colostrum as one ingredient in a blend:
- Primal Queen PQ7 lists bovine colostrum standardized to 40% immunoglobulins alongside saffron, dihydroberberine, chromium and other ingredients. The label lists milk as an allergen, the capsules are gelatin, and it is labeled for healthy adults 18 and older.
- DR Vitamin Solutions Nighttime Fat Burner is a stimulant-free amino acid capsule that includes bovine colostrum powder with L-glutamine, L-arginine and L-ornithine. It uses a bovine gelatin shell and is not suitable for anyone avoiding dairy-derived ingredients.
In both, colostrum is one of several ingredients, so neither label tells you what colostrum alone would do.
Frequently Asked Questions
What is colostrum?
It is the first milk produced after birth. Supplements use bovine colostrum from cows, collected in the first days after calving and dried into a powder.
What are the main colostrum benefits?
Small trials in athletes found less gut permeability after hard exercise and fewer days with cold-like symptoms. The trials were small and often at risk of bias, so the benefits are not established.
Does colostrum help leaky gut?
Studies found lower readings on gut permeability tests around intense exercise, but they were tiny and short. There is no good evidence that it improves everyday digestion.
Does colostrum boost the immune system?
Pooled trials found little or no change in antibody levels or immune cell counts in active adults.
Is colostrum safe if I am lactose intolerant or allergic to milk?
Avoid it with a milk allergy. With lactose intolerance, check the label, since lactose content varies and some powders remove it.
Can colostrum help with weight loss?
There are no good human trials showing that colostrum causes weight loss.
Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting any supplement, especially if you take medicines. 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: How to Improve Gut Health: Evidence-Based Habits and What Tests Can’t Tell You, Akkermansia Probiotic: What It Is, Live vs Pasteurized and How to Read the Label, Third Party Tested Supplements: What USP, NSF and Other Seals Mean.