What are the side effects of taking colostrum supplements?

October 6, 2025 •

3 min read

Over 75% of athletes use supplements to boost performance, with some adding colostrum to their routine, but what are the side effects of taking colostrum supplements? While bovine colostrum is generally considered safe for most people, some individuals may experience mild gastrointestinal discomfort, allergic reactions, or adverse effects related to pre-existing conditions.

Quick Summary

Potential side effects of bovine colostrum supplements include mild digestive issues, such as nausea, bloating, and gas, as well as more serious allergic reactions for those with dairy sensitivities. The unregulated nature of supplements also poses risks related to product quality and potential interactions with certain medications.

Key Points

Mild GI issues are common: Some people may experience temporary nausea, gas, bloating, or diarrhea, especially when first starting colostrum supplements.
Dairy allergies are a contraindication: Individuals with a cow's milk protein allergy should not take colostrum, as it contains casein and can trigger severe allergic reactions.
Caution is needed for certain groups: Pregnant or breastfeeding women, people with immunosuppressed conditions, and those with certain kidney or liver diseases should consult a doctor before use.
Potential for drug interactions: Colostrum may interfere with immunosuppressant medications and could affect calcium and blood sugar levels.
Choose third-party tested products: The supplement industry lacks strict FDA regulation, so opting for third-party verified products helps ensure quality and reduce contamination risks.
Consult a healthcare professional: Always speak with a doctor or dietitian before starting colostrum to assess its appropriateness and safety for your individual health profile.

Common Gastrointestinal Side Effects

Bovine colostrum is typically well-tolerated, but the most frequently reported side effects are mild and affect the digestive system. These symptoms often occur when a person first begins taking the supplement and may lessen over time as the body adjusts. Starting with a smaller dose and gradually increasing it can help.

Digestive Upset

Some individuals experience gastrointestinal symptoms after taking colostrum, particularly if they are sensitive to dairy or consume a large dose quickly. These can include nausea, bloating, gas, and diarrhea.

Allergic Reactions and Contraindications

For certain individuals, the side effects of colostrum supplements can be more severe. As a dairy-derived product, colostrum contains milk proteins like casein, which can trigger adverse reactions in people with cow's milk allergies.

Milk Protein Allergy vs. Lactose Intolerance

It is important to distinguish between a milk protein allergy, which is an immune system response, and lactose intolerance, a digestive issue. Individuals with a cow's milk protein allergy must avoid colostrum to prevent severe reactions, while those with lactose intolerance may experience digestive upset depending on the lactose content.

Who Should Exercise Caution?

Certain populations should consult a healthcare provider before using colostrum:

Dairy Allergies: Avoid if you have a diagnosed cow's milk protein allergy.
Pregnancy and Breastfeeding: Insufficient safety information exists; avoidance is recommended.
Immunocompromised Individuals: Seek medical advice due to potential interactions with immunosuppressants.
Kidney or Liver Issues: Caution is advised due to potential effects on calcium levels or liver function.

Potential Drug Interactions

While the risk is low, colostrum can potentially interfere with certain medications.

Interactions with Immunosuppressants

Colostrum contains immune-modulating compounds that could potentially interfere with immunosuppressant drugs used by organ transplant recipients or individuals with autoimmune diseases.

Other Potential Interactions

Consultation with a doctor is necessary if taking medications for conditions like diabetes, high blood pressure, or bleeding disorders. Colostrum can affect calcium levels and may impact blood sugar.

Concerns About Supplement Quality and Sourcing

Supplements are not regulated by the FDA before sale, leading to potential variability in product quality and contamination risks.

Unregulated Market Risks

Lack of regulation can result in inconsistent potency, contamination risks from harmful substances, and inaccurate labeling. To mitigate these risks, choose products from reputable manufacturers that use third-party testing organizations like NSF, USP, or ConsumerLab to verify purity and potency.

Comparison of Mild vs. Allergic Colostrum Reactions


Feature	Mild GI Side Effects	Allergic Reactions	Potential Interactions	Contamination Risks
Cause	Initial adjustment to supplement, dose, or lactose sensitivity.	Immune system reaction to milk proteins, like casein.	Active compounds interfering with prescription drugs.	Poor sourcing and manufacturing practices.
Symptoms	Nausea, bloating, gas, temporary diarrhea.	Itching, hives, swelling, difficulty breathing.	Reduced drug effectiveness, changes in calcium/blood sugar levels.	Illness from bacteria (e.g., Salmonella), heavy metal exposure.
Severity	Generally mild and self-resolving.	Can be severe and potentially life-threatening.	Dependent on the medication; can be serious.	Can cause serious foodborne illness.
Risk Group	Lactose-intolerant individuals, new users.	Individuals with a diagnosed cow's milk protein allergy.	Individuals on immunosuppressants or certain chronic disease medications.	Consumers of low-quality, unregulated products.

Important Considerations Before Supplementing

Before adding any new supplement, it is important to be cautious and informed:

Consult a Healthcare Provider: Speak with a doctor or registered dietitian, especially with pre-existing conditions or if taking medications.
Verify Allergies: Avoid colostrum if you have a cow's milk allergy.
Start Low and Go Slow: Begin with a lower dose to minimize potential digestive upset.
Choose High-Quality Products: Look for supplements independently tested and certified by third-party organizations.
Prioritize Overall Wellness: Remember supplements complement, not replace, a balanced diet, exercise, and sleep.

For more information on digestive and immune health, consider exploring resources from reputable health institutions like the Mayo Clinic.

Conclusion

While colostrum supplements may offer benefits, they carry potential side effects, primarily mild digestive issues. However, serious allergic reactions are possible for those with dairy sensitivities. The lack of strict regulation in the supplement industry necessitates choosing high-quality products. Consulting a healthcare professional is crucial, especially for individuals with existing health conditions or those on medication, to ensure safety and suitability.

Frequently Asked Questions

The most common side effects are mild gastrointestinal issues, such as nausea, bloating, gas, and diarrhea, particularly when a person first starts taking the supplement or takes a large dose.

If you are lactose intolerant, you may experience digestive discomfort from colostrum due to its lactose content. Supplements with reduced lactose may be available, but it's best to discuss this with your doctor before use.

No, if you have a cow's milk protein allergy, you should not take bovine colostrum. It contains milk proteins that can trigger a severe allergic immune response.

Since supplements are not regulated by the FDA, there is a risk of inconsistent potency and potential contamination with pathogens, heavy metals, pesticides, or antibiotics, especially in low-quality products.

Yes, colostrum may potentially interact with some medications, most notably immunosuppressants. It can also affect calcium levels. Always consult your healthcare provider before taking colostrum if you are on any prescription drugs.

Individuals with a cow's milk protein allergy, those who are pregnant or breastfeeding, people on immunosuppressants, and those with specific pre-existing health conditions like kidney or liver disease should avoid or be very cautious with colostrum supplements.

Look for supplements from reputable brands that undergo third-party testing and certification from organizations like NSF International, USP, or ConsumerLab. This helps ensure product purity and potency.

Concerns have been raised about whether the growth factors designed for newborns could risk activating certain cells in adults. However, more research is needed, and absorption of these factors may be limited.