Who Should Avoid Lactoferrin? Important Precautions to Know

November 1, 2025 •

4 min read

As a protein naturally found in both human and cow's milk, lactoferrin is widely recognized as safe, but certain individuals, including those with milk protein allergies, should avoid lactoferrin supplements. While beneficial for many, lactoferrin is not universally suitable and requires special consideration before use.

Quick Summary

This guide outlines specific groups who should be cautious with or avoid lactoferrin, such as individuals with milk protein allergies, autoimmune disorders, or those on certain medications.

Key Points

Milk Protein Allergy: Individuals with a confirmed allergy to cow's milk proteins should avoid bovine-sourced lactoferrin to prevent severe allergic reactions, including anaphylaxis.
Autoimmune Conditions: Those with certain autoimmune diseases like rheumatoid arthritis should consult a specialist, as autoantibodies against lactoferrin have been identified in these patients.
Compromised Immunity: Patients with compromised immune systems (e.g., HIV/AIDS, cancer treatment) should seek professional medical advice before use.
Medication Interactions: Lactoferrin can interfere with immunosuppressants and antibiotics; it should be taken at least 2 hours apart from other prescription drugs.
Sensitive Populations: Pregnant, breastfeeding women, and young children should only use lactoferrin under a healthcare professional's supervision due to limited safety data on high doses.
High Doses: Excessive amounts may cause mild side effects like diarrhea, constipation, or skin rash; dosage should be adjusted if these occur.
Source Matters: Vegans and those avoiding dairy must ensure their supplement is not bovine-derived, as most commercial lactoferrin is from cow's milk.

What is Lactoferrin?

Lactoferrin is a multifunctional glycoprotein present in milk and various other bodily fluids, including saliva, tears, and nasal secretions. It is a critical component of the immune system and has roles in transporting and regulating iron absorption. Due to its antimicrobial, antioxidant, and anti-inflammatory properties, it has become a popular dietary supplement. However, despite its generally favorable safety profile, it's not suitable for everyone and requires careful consideration, especially regarding the source and potential interactions.

Key Groups Who Should Avoid Lactoferrin

While lactoferrin is safe for most people in moderation, several groups should be especially cautious or avoid it completely. These precautions are often related to the protein's origin, its impact on the immune system, and potential drug interactions.

Individuals with Milk Protein Allergies

This is one of the most critical contraindications. Since most commercially available lactoferrin supplements are derived from bovine (cow's) milk, they contain cow's milk proteins. For those with a confirmed milk protein allergy (not to be confused with lactose intolerance), consuming lactoferrin, especially from colostrum, can trigger a severe allergic reaction. Symptoms can range from hives and digestive upset to a life-threatening anaphylactic shock. Even highly purified products, while better for lactose intolerance, may still carry a risk of contamination and should be used with extreme caution. Always consult a healthcare provider if you have a known milk protein allergy.

Those with Certain Autoimmune Diseases

Lactoferrin has a complex relationship with the immune system. While some research suggests its immunomodulatory properties could benefit certain autoimmune conditions, other studies have found that autoantibodies against lactoferrin are present in inflammatory disorders like rheumatoid arthritis and autoimmune liver disease. The potential for lactoferrin to trigger or exacerbate autoimmune responses is not fully understood, making it a risky supplement for those with active autoimmune conditions. People with a compromised immune system, such as those with HIV/AIDS or undergoing cancer treatment, should also consult a physician before using lactoferrin.

People on Certain Medications

Lactoferrin has the potential to interact with some prescription medications, necessitating a doctor's oversight.

Immunosuppressants: Lactoferrin's ability to modulate immune function could interfere with the action of immunosuppressant drugs.
Antibiotics: Some research indicates that lactoferrin can influence how antibiotics work, so it's often advised to take them at least two hours apart.
Other Medications: Always inform your doctor about any supplements you are taking, especially if you are on multiple medications, to avoid unintended interactions.

Pregnant and Breastfeeding Women

While lactoferrin is a natural component of breast milk, and supplementation may be beneficial in certain cases, caution is advised for pregnant and breastfeeding women regarding medicinal doses. The effects of high-dose supplementation in these sensitive populations are not yet fully understood due to limited research. Always consult a healthcare provider before starting any new supplement during pregnancy or lactation.

People Experiencing Side Effects from High Doses

Taking excessive amounts of lactoferrin can lead to mild but uncomfortable side effects, particularly affecting the gastrointestinal system. If you experience any of the following, you should either reduce your dosage or stop taking the supplement altogether:

Gastrointestinal Distress: This can include constipation, diarrhea, or bloating, especially with higher dosages.
Reduced Appetite: Some people report a loss of appetite when taking very high doses.
Skin Rashes: In rare cases, skin rashes have been reported as a side effect.

Comparison of Lactoferrin Suitability


Condition / Factor	Suitability for Lactoferrin	Precautions and Considerations
Milk Protein Allergy	Avoid	Most supplements are derived from cow's milk and can cause severe allergic reactions, including anaphylaxis.
Lactose Intolerance	Consult Doctor	Highly purified products may be suitable, but cross-contamination is a risk. Depends heavily on the product's source and purity.
Autoimmune Disease	Consult Specialist	Potential for immunomodulation could be risky. Autoantibodies have been found in patients with conditions like rheumatoid arthritis.
Taking Immunosuppressants	Avoid or Consult Doctor	Risk of interaction that could interfere with medication effectiveness.
Taking Antibiotics	Consult Doctor	Advised to separate intake by at least 2 hours to avoid potential interference.
Pregnancy/Breastfeeding	Consult Doctor	Limited research on high medicinal doses. Avoid until more is known.
Vegan Diet	Check Source	Ensure the supplement is not bovine-derived. Some human-identical options are available, but require checking for processing details.
Infants & Young Children	Consult Doctor	Should only be given under medical supervision, especially for children under 4.

Final Considerations Before Supplementing

Before starting any new supplement, including lactoferrin, it is always best practice to have a conversation with your healthcare provider. They can help you evaluate the risks based on your personal health history, pre-existing conditions, and any medications you are currently taking. Additionally, it is vital to source your supplements from reputable brands that use third-party testing to ensure product purity and reduce the risk of cross-contamination with common allergens. While lactoferrin is a promising health aid, informed decisions are key to reaping its benefits while avoiding potential harm.

For more detailed information on the complex immune system interactions of lactoferrin, research published on the National Institutes of Health website can be a valuable resource, such as this study on its role in immune modulation: Lactoferrin as a Natural Immune Modulator.

Frequently Asked Questions

Yes, in many cases, especially with highly purified products. Lactoferrin is a protein, and lactose intolerance is an inability to digest the milk sugar, lactose. However, if you have a milk protein allergy, you should avoid it unless advised otherwise by a doctor.

Lactoferrin is generally well-tolerated, but high doses may cause mild gastrointestinal issues like diarrhea, constipation, bloating, or, in rare cases, a skin rash.

Individuals with certain autoimmune diseases and those with a compromised immune system (e.g., from cancer treatment or HIV/AIDS) should consult their doctor before using lactoferrin due to its immune-modulating effects.

Yes, lactoferrin can potentially interact with immunosuppressants and antibiotics. It is recommended to take it at least two hours away from any prescription medication.

While naturally occurring in breast milk, high-dose lactoferrin supplementation during pregnancy and breastfeeding is not well-studied and should only be considered after consulting a healthcare provider.

Yes, bovine lactoferrin is derived from cow's milk and is structurally different from human lactoferrin, though it is bioavailable. This difference is why individuals with milk protein allergies may react to bovine-sourced supplements.

Vegans must check the product's packaging to ensure it is not derived from bovine or other animal sources. Some human-identical lactoferrin exists, but due diligence is required to check for dairy contamination.