Who Should Not Take Colostrum: 8 Groups That Need Caution

Updated September 14, 2026

Bovine colostrum is generally well tolerated in clinical trials, with most reported side effects limited to mild bloating or loose stools. But "generally well tolerated" is not the same as "safe for everyone." Because it is a concentrated dairy product that carries immunoglobulins, growth factors, and lactose, a handful of groups should either avoid it entirely or check with a clinician before starting. This guide walks through eight of them, explains what the evidence does and does not say, and points to practical alternatives where they exist.

• Cow's milk protein allergy is the one clear contraindication. Colostrum contains casein and whey proteins, so it can trigger the same reactions as milk.
• Lactose intolerance is a caution, not a ban. Colostrum has less lactose than mature milk, and some products are lactose-reduced.
• Pregnancy, breastfeeding, and infancy lack safety data. Absence of evidence of harm is not evidence of safety.
• Drug-tested athletes face a doping-policy issue. Colostrum is not banned, but the World Anti-Doping Agency (WADA) advises against it because of its IGF-1 content.
• Immunosuppressed people and those on restricted diets should involve their care team before adding any concentrated dairy supplement.

Why colostrum deserves more care than ordinary milk

Colostrum is the first milk a cow produces in the 24 to 72 hours after calving. Compared with mature milk, it holds roughly four to five times more protein, a much higher concentration of immunoglobulin G (IgG), and measurable amounts of insulin-like growth factor 1 (IGF-1) and other bioactive peptides. A typical commercial powder standardised to 20 to 30 percent IgG delivers about 2 to 3 g of IgG per 10 g serving, along with roughly 35 to 40 kcal and 4 to 6 g of protein. For a general overview of what is in the product, see what colostrum is and how it is made.

Those same features that make colostrum interesting to researchers are exactly why certain people should be cautious. The list below is ordered roughly from strongest to weakest evidence for concern.

1. People with cow's milk protein allergy

This is the only group for which the advice is unambiguous: do not take bovine colostrum. Cow's milk allergy is an immune reaction to milk proteins, most often casein, beta-lactoglobulin, and alpha-lactalbumin. All of these are present in colostrum, often at higher concentrations than in mature milk. Reactions can range from hives and vomiting to anaphylaxis, and there is no evidence that colostrum processing removes the allergens.

Cow's milk allergy is most common in infants and young children, affecting an estimated 2 to 3 percent in the first year of life, but a minority carry it into adulthood. Adults who developed a milk allergy later in life should treat colostrum exactly as they would a glass of milk.

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2. People with lactose intolerance

Lactose intolerance is an enzyme deficiency, not an allergy, so the question is dose rather than presence. Raw bovine colostrum from the first milking contains roughly 2.5 g of lactose per 100 mL, compared with about 4.8 g per 100 mL in mature milk. Once dried into a powder, a standard 10 g serving of whole colostrum typically carries somewhere in the range of 1 to 2 g of lactose, versus about 12 g in a 240 mL glass of milk.

Many lactose-intolerant adults tolerate up to 12 g of lactose in a single sitting without symptoms, so a small colostrum dose may well be fine. Those with more severe intolerance can look for lactose-reduced or high-IgG concentrated products, which strip out much of the sugar while keeping the immunoglobulin fraction. Starting with a half serving and watching for gas, bloating, or diarrhoea is a sensible approach. Our dosage and safety guide covers titration in more detail.

3. Pregnant and breastfeeding women

No controlled trials have evaluated bovine colostrum supplements during pregnancy or lactation. That does not mean it is dangerous; colostrum is, after all, a food, and pregnant women drink milk. But supplements deliver a concentrated dose of growth factors and immunoglobulins, and the effect of that concentration on a developing fetus or a nursing infant has simply not been studied. The cautious position, and the one most clinicians would take, is to skip it during these periods unless a doctor specifically recommends it.

4. Infants and young children

Some paediatric trials have used bovine colostrum, particularly in preterm infants and children with diarrhoeal illness, but these were conducted under medical supervision with pharmaceutical-grade products. Over-the-counter colostrum powder is not a substitute for infant formula or breast milk, and it should never be used to replace either. For toddlers and older children, the main issues are undiagnosed milk allergy and the lack of dosing data. Any use in children belongs in a conversation with a paediatrician, not a supplement aisle.

5. People who are immunocompromised or taking immunosuppressants

This group includes organ-transplant recipients, people on chemotherapy, and those taking biologic drugs for autoimmune disease. Two separate concerns apply. The first is microbiological: unpasteurised or minimally processed colostrum can carry bacteria, and an impaired immune system is less able to cope with a contaminated batch. Choosing a product that is pasteurised, low-heat processed, and third-party tested reduces but does not eliminate this risk.

The second concern is theoretical. Colostrum contains bioactive compounds that may modulate immune activity in the gut. Whether this matters clinically for someone whose immune system is being deliberately suppressed is unknown, because the studies have not been done. Given the uncertainty, the supplement should be discussed with the prescribing specialist rather than added independently.

6. Athletes subject to anti-doping testing

Bovine colostrum is not on the WADA Prohibited List. However, WADA has stated that it does not recommend colostrum ingestion because it contains IGF-1 and other growth factors that could, in principle, influence an athlete's anti-doping test results. Some early research found that daily colostrum supplementation raised circulating IGF-1 in athletes, though later trials were inconsistent, and most of the ingested peptide is probably degraded in the adult gut.

The practical risk is small but real. An elevated IGF-1 reading could complicate an athlete biological passport review even without a formal violation. Competitive athletes under testing should weigh a modest and uncertain benefit against a compliance headache, and should consult their federation's medical staff before use.

7. People with hormone-sensitive conditions or growth-factor concerns

This is the weakest evidence category on the list, and it is included for completeness rather than because harm has been shown. Colostrum contains IGF-1 at concentrations that vary widely between batches and processing methods. Because IGF-1 signalling is involved in cell growth, some people with a personal or family history of hormone-sensitive cancers prefer to avoid concentrated sources. No study has linked colostrum supplementation to cancer risk, and the amounts involved are small relative to what the body produces. Still, anyone under active treatment or surveillance for such a condition should ask their oncologist first.

8. People on protein-restricted or otherwise restricted diets

Colostrum powder is typically 40 to 60 percent protein by weight, so a 10 g serving contributes 4 to 6 g of protein and a 20 g serving roughly double that. For most adults this is trivial. For someone with advanced chronic kidney disease who has been told to limit protein to a fixed daily gram count, it is not, and the supplement should be counted or skipped. Separately, colostrum is an animal product and is not suitable for vegans, and observant consumers should check for kosher or halal certification because collection and processing practices vary between suppliers.

Comparing options for cautious users

Values are approximate and vary by brand and processing. Reading the certificate of analysis, where a brand provides one, is the only way to know what a specific product contains. Our guide to choosing a colostrum supplement explains how to read those documents.

Signs you should stop taking it

1. Hives, swelling of the lips or throat, or difficulty breathing. Stop immediately and seek emergency care; this pattern suggests an allergic reaction.
2. Persistent diarrhoea, cramping, or bloating lasting more than a few days after starting. Reduce the dose or switch to a lactose-reduced product.
3. Any new symptom in someone who is immunosuppressed, particularly fever or gastrointestinal illness.
4. Unexpected findings on a hormone panel or anti-doping screen in athletes. Disclose supplement use to the reviewing physician.

FAQ

Is colostrum safe if I only have mild lactose intolerance?

Probably, though individual tolerance varies. A standard 10 g serving of whole colostrum powder contains far less lactose than a glass of milk, and most people with mild intolerance handle small amounts without symptoms. Start with half a serving taken with food, watch for bloating or loose stools over a few days, and consider a lactose-reduced product if symptoms appear.

Can I take colostrum if I have a dairy sensitivity but not a diagnosed allergy?

"Sensitivity" is a vague term that can cover lactose intolerance, mild non-immune reactions, or an undiagnosed true allergy. If you have ever had hives, swelling, or breathing difficulty after dairy, treat it as a possible allergy and avoid colostrum until a clinician has tested you. If your reaction is limited to digestive discomfort, the lactose guidance above applies.

Does colostrum interact with prescription medications?

No specific drug interactions have been documented in the literature, but the research base is thin. The groups most likely to have an issue are people on immunosuppressants, where the concern is theoretical immune modulation, and people on protein-restricted regimens. As with any supplement, tell your pharmacist or doctor what you are taking so it can be recorded and reviewed.

Will colostrum cause a positive doping test?

Colostrum itself is not prohibited, and no athlete has been sanctioned solely for taking it. The issue is that its IGF-1 content could, in theory, nudge growth-factor readings on an athlete biological passport. WADA has said it does not recommend colostrum for this reason. Tested athletes should weigh this against the modest and mixed evidence of performance benefit described on our FAQ page.

Sources

• Playford RJ, Weiser MJ. Bovine Colostrum: Its Constituents and Uses. Nutrients, 2021.
• Rathe M, Müller K, Sangild PT, Husby S. Clinical applications of bovine colostrum therapy: a systematic review. Nutrition Reviews, 2014.
• Davison G. The Use of Bovine Colostrum in Sport and Exercise. Nutrients, 2021.
• Ulfman LH, Leusen JHW, Savelkoul HFJ, Warner JO, van Neerven RJJ. Effects of Bovine Immunoglobulins on Immune Function, Allergy, and Infection. Frontiers in Nutrition, 2018.
• Mero A, Miikkulainen H, Riski J, Pakkanen R, Aalto J, Takala T. Effects of bovine colostrum supplementation on serum IGF-I, IgG, hormone, and saliva IgA during training. Journal of Applied Physiology, 1997.

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