Understanding Who Should Not Drink Whey Protein?

October 21, 2025 •

5 min read

An estimated 65% of the global population has a reduced ability to digest lactose, a component found in whey protein. This, along with other health factors, influences who should not drink whey protein, highlighting the need to assess individual dietary and health needs for safe supplementation.

Quick Summary

Certain health conditions like dairy allergies, kidney or liver disease, and severe lactose intolerance may make whey protein unsafe. Excessive intake can also cause digestive issues. Consulting a doctor or dietitian is crucial before beginning supplementation.

Key Points

Avoid with Milk Allergy: Individuals with a dairy allergy must completely avoid whey protein, as it is a milk derivative that can trigger a severe immune response.
Caution with Lactose Intolerance: While some lactose-intolerant individuals can tolerate whey protein isolate, those with severe intolerance or issues with whey concentrate should opt for a dairy-free alternative to avoid digestive upset.
Risky for Kidney and Liver Disease: High protein intake from supplements like whey can be dangerous for people with pre-existing kidney or liver conditions, placing an unnecessary burden on these organs.
Consult a Doctor if Pregnant or Breastfeeding: Pregnant and breastfeeding women should seek medical advice before using whey protein supplements due to potential contaminants and the lack of conclusive safety research on specific products.
Not Recommended for Most Children: For most healthy children, protein supplements are unnecessary and potentially harmful to their developing organs; a whole-food diet is preferred unless directed by a pediatrician.
Check for Medication Interactions: Whey protein can reduce the effectiveness of certain antibiotics, bisphosphonates, and levodopa; timing supplement intake is crucial to prevent these interactions.
Explore Alternatives: Safe and effective alternatives like plant-based proteins (pea, hemp) or egg white protein are excellent options for those who need to avoid whey.

What is Whey Protein?

Whey is one of the two main proteins found in cow's milk, the other being casein. During the cheese-making process, whey is separated from the solid curds and processed into a powdered form. It is a high-quality, complete protein, meaning it contains all nine essential amino acids necessary for the body. Its rapid absorption makes it a popular supplement for muscle growth and repair, particularly among athletes and bodybuilders. However, because it originates from dairy, it is not suitable for everyone, and certain individuals should avoid it entirely or exercise caution.

Health Conditions That Preclude Whey Protein Consumption

For some people, consuming whey protein can exacerbate existing health issues rather than improve their nutritional status. It is crucial to consult a healthcare professional before adding any new supplement, especially for individuals with chronic conditions.

Kidney Disease

For healthy individuals, moderate whey protein intake is generally considered safe for the kidneys. However, a high-protein diet puts an increased workload on the kidneys to filter out waste products. In people with pre-existing kidney disease or compromised kidney function, this extra strain can be dangerous and worsen their condition. A doctor will likely recommend a managed protein intake from whole foods instead of a supplement.

Liver Conditions

The liver plays a vital role in processing proteins and removing toxic substances like ammonia from the blood. For those with severe liver disease, such as hepatic encephalopathy, excessive protein intake can overwhelm the liver and lead to a dangerous buildup of ammonia. While moderate protein can aid liver repair in some cases, unsupervised high-dose whey supplementation is not recommended and should be discussed with a specialist.

Certain Medication Interactions

Whey protein can interfere with the absorption and effectiveness of specific medications. If you are on any of the following, a pharmacist or doctor should be consulted:

Antibiotics: Specifically quinolone and tetracycline antibiotics. The calcium in whey can bind to these drugs, reducing their absorption. It is recommended to take the supplement at least two hours before or four to six hours after taking the medication.
Levodopa: Used to treat Parkinson's disease, levodopa's absorption can be reduced by whey protein.
Bisphosphonates: For osteoporosis, these drugs can be less effective if taken too closely with whey protein.

Allergic Reactions and Digestive Issues

Not all adverse reactions to whey are the same. Understanding the distinction between a true allergy and an intolerance is key to determining if whey is right for you.

Dairy Allergies vs. Lactose Intolerance

Dairy Allergy: This is an immune system response to the proteins in milk, including whey. Symptoms can range from mild (hives, rashes) to severe, life-threatening anaphylaxis involving swelling and difficulty breathing. Individuals with a confirmed dairy allergy must avoid all whey protein products.
Lactose Intolerance: This is a digestive issue, not an allergy, caused by a lack of the enzyme lactase needed to break down lactose, the sugar in milk. Symptoms include bloating, gas, cramps, and diarrhea. While whey protein concentrate contains noticeable lactose, processed forms like whey protein isolate contain very little and may be tolerable for some with mild intolerance.

Specific Populations That Require Caution

Children and Adolescents

For most healthy children, protein powders are unnecessary and can be harmful. Excess protein can place a burden on developing kidneys and may lead to unwanted weight gain due to added calories. Pediatricians recommend focusing on protein from whole foods like milk, eggs, meat, and legumes. Supplements should only be used under a doctor's supervision for underweight children or those with specific metabolic needs.

Pregnant and Breastfeeding Women

While protein needs increase during pregnancy and breastfeeding, most can meet these needs through a balanced diet. There is not enough reliable research to confirm the safety of whey protein supplements during pregnancy, especially concerning additives, artificial sweeteners, and potential contaminants. It is best to consult an obstetrician or registered dietitian before use, and to prioritize protein from whole-food sources.

A Comparison of Protein Sources


Feature	Whey Protein Concentrate	Whey Protein Isolate	Plant-Based Proteins (e.g., Pea, Hemp)
Lactose Content	Higher levels, can cause issues for the lactose intolerant.	Very low levels due to further processing.	Generally zero, suitable for lactose-free diets.
Processing	Minimally processed, retains some fat and carbohydrates.	Highly processed to remove most fat and lactose.	Processing varies, focuses on separating protein from plant source.
Digestibility	Can be difficult for lactose intolerant individuals.	Easier to digest due to low lactose content.	May be easier for some, especially if sensitive to dairy.
Allergies	Unsuitable for those with dairy allergies.	Unsuitable for those with dairy allergies.	Excellent alternative for those with dairy allergies.
Completeness	Complete protein source.	Complete protein source.	Can be incomplete; often blended to provide a complete amino acid profile.

Alternatives for Those Who Cannot Tolerate Whey

For those who cannot or should not consume whey protein, there are numerous safe and effective alternatives available. These options can still help meet your protein goals without the associated risks.

Casein Protein

Also milk-derived, casein is separated from whey during cheesemaking and forms the solid curds. It is a slow-digesting protein, making it ideal for sustained amino acid release, such as before bed. Most of the lactose is removed, and it can sometimes be tolerated by those with mild lactose intolerance, but should be avoided with a dairy allergy.

Plant-Based Protein

Many plant-based proteins, often sold as blends, offer complete amino acid profiles suitable for vegans and those with dairy allergies. Common sources include:

Pea Protein: Often blended with other proteins to ensure a complete amino acid profile.
Hemp Protein: A complete protein with the added benefit of omega-3 fatty acids.
Brown Rice Protein: A hypoallergenic option that works well blended with pea protein.
Soy Protein: A complete protein source, though some individuals may have a soy sensitivity.

Egg White Protein

An excellent dairy-free alternative, egg white protein is highly digestible and provides a complete amino acid profile. It's a great option for those with milk or lactose issues.

Conclusion: Making Informed Nutritional Choices

Whey protein is a valuable supplement for many, but it is not a one-size-fits-all solution. Those with dairy allergies, kidney or liver disease, certain medical conditions, or taking specific medications should avoid or consult a doctor before consuming it. Children, and pregnant or breastfeeding women, should also proceed with caution and professional guidance. Fortunately, a variety of effective alternatives, including plant-based and casein proteins, exist to meet your nutritional needs safely. The key is to listen to your body and prioritize professional medical advice to ensure your dietary choices support, rather than jeopardize, your health.

Always Consult a Professional

Before incorporating any new supplement into your diet, it is essential to speak with a healthcare provider or registered dietitian. They can provide personalized advice based on your medical history, dietary needs, and fitness goals, ensuring you make the safest and most effective nutritional choices for your body.

Frequently Asked Questions

No, if you are allergic to whey protein, you are also allergic to milk. Whey protein is one of the proteins found in milk, so an allergy to it means you will have a reaction to milk as well.

For healthy individuals with normal kidney function, moderate whey protein consumption is not known to be harmful. However, a high protein intake can strain kidneys, which is why it is dangerous for people with pre-existing kidney disease.

Whey protein isolate undergoes more extensive processing to remove most of the fat and lactose, making it the best option for those with lactose sensitivity. Whey protein concentrate retains higher levels of lactose.

Yes, for some individuals, particularly those with lactose intolerance, whey protein can cause digestive issues such as bloating, gas, cramps, and diarrhea. Drinking it too quickly or in high doses can also cause discomfort.

High doses can cause various side effects, including digestive upset, increased thirst, headaches, and fatigue. Excessive intake, especially without proper exercise, could also potentially strain the liver and kidneys over the long term.

Excellent alternatives include plant-based protein powders (such as pea, hemp, or soy), casein protein, or egg white protein. These can provide complete protein without triggering dairy-related issues.

There is not enough reliable data on the safety of many whey protein supplements during pregnancy due to potential contaminants and unregulated ingredients. It is best to consult a healthcare provider and prioritize whole-food protein sources.

Most children get enough protein from a balanced diet of whole foods. Protein supplements are generally unnecessary and can place a metabolic burden on developing organs. Only give protein powder to a child under a pediatrician's guidance.