Are there any risks to taking collagen?

November 17, 2025 •

4 min read

Approximately 1 in 10 individuals may experience side effects from collagen supplements, with digestive upset being a common issue. Before starting a collagen regimen, understanding the potential risks is important. The safety of collagen use depends on individual health and product quality.

Quick Summary

This article explores the potential downsides of collagen supplements, including digestive problems, allergic reactions, and possible kidney health concerns. It explains who should exercise caution and how to mitigate risks by choosing quality products and consulting a healthcare provider.

Key Points

Digestive Issues: Collagen supplements can cause mild gastrointestinal upset, including bloating, nausea, and diarrhea, especially at high doses.
Allergic Reactions: Individuals with allergies to fish, shellfish, or eggs should check the source of collagen to avoid reactions, as many supplements are animal-derived.
Kidney Stone Risk: People with a history of kidney stones or kidney disease should consult a doctor, as the hydroxyproline in collagen can increase oxalate, a kidney stone precursor.
Contamination Concerns: Lack of FDA regulation means some supplements may contain heavy metals; look for third-party certifications like NSF or USP to ensure product purity.
Medication Interactions: While uncommon, high protein intake from collagen may affect certain blood pressure medications; always consult a doctor if you are on medication.
Autoimmune Consideration: For those with autoimmune disorders, the introduction of foreign proteins might trigger an immune response, warranting medical advice.
Safe Consumption: Most healthy people can safely take collagen daily at recommended doses, with long-term use considered safe, but consistency is key to seeing and maintaining benefits.

Understanding the Potential Risks of Collagen Supplements

Collagen supplements are a popular choice for improving skin, hair, and joint health. However, like other supplements, they are not without potential downsides. Understanding the specific risks is crucial for making informed choices.

Digestive Issues and Gastrointestinal Discomfort

Digestive distress is one of the most reported side effects. Some users may experience symptoms, such as:

Bloating and a feeling of fullness.
Nausea and upset stomach.
Diarrhea or, in some cases, constipation.
Heartburn.

These issues can sometimes be attributed to the additives in a particular supplement or an individual's sensitivity to the hydrolyzed collagen peptides themselves. Starting with a smaller dose and gradually increasing it can help the body adjust. Choosing a high-quality, hydrolyzed collagen can also improve digestibility and absorption.

Allergic Reactions

Collagen supplements are typically derived from animal sources, such as bovine (cows), marine (fish), or chicken. This poses a risk of allergic reactions for people with pre-existing allergies to these sources. Symptoms of an allergic reaction can range from mild skin rashes, itching, or swelling to more severe cases of anaphylaxis. It is essential to:

Read labels carefully to identify the collagen source.
Avoid marine-sourced collagen if you have fish or shellfish allergies.
Check for other potential allergens, such as eggs, which are sometimes included in multi-collagen blends.
Consult a doctor if you experience any signs of an allergic reaction.

Kidney Health Concerns and Potential for Kidney Stones

For most people with healthy kidneys, collagen supplementation is unlikely to cause problems. However, caution is advised for individuals with a history of kidney disease, kidney stones, or a predisposition to them. Collagen contains the amino acid hydroxyproline, which is converted into oxalate in the body. High levels of oxalate can lead to the formation of calcium oxalate kidney stones. A few precautions are recommended for those at risk:

Hydration is Key: Drinking plenty of water can help flush excess oxalate from the system.
Maintain Calcium Intake: Adequate dietary calcium helps bind with oxalate in the intestines, preventing it from being absorbed and reaching the kidneys.
Professional Consultation: Individuals with kidney concerns should speak with a nephrologist before starting a collagen supplement.

Contaminants in Unregulated Supplements

One of the most significant risks associated with collagen, and supplements in general, is the lack of strict regulation by governing bodies like the FDA in many countries. This can lead to variations in product quality and purity. Some products have been found to contain heavy metals, such as lead, cadmium, and arsenic, due to contamination during processing. To minimize this risk:

Choose Reputable Brands: Opt for companies with a strong reputation for transparency and quality control.
Look for Third-Party Testing: Seek products with certifications from independent organizations like NSF International, USP, or Clean Label Project, which verify product content and purity.
Review Sourcing: Companies that provide traceable supply chain information for their bovine, marine, or other collagen sources offer greater assurance of a clean product.

Drug Interactions and Autoimmune Conditions

While major drug interactions with collagen are not well-documented, caution is warranted. Some evidence suggests that high-protein diets, which can result from high-dose collagen intake, might interfere with certain blood pressure medications. Additionally, some autoimmune disease patients, like those with rheumatoid arthritis or scleroderma, should consult a doctor, as introducing foreign proteins could potentially trigger an immune response. Anyone on medication or with a chronic health condition should always discuss supplementation with a healthcare provider.

Long-Term Safety and Considerations

Studies suggest that daily collagen supplementation at recommended doses (e.g., 2.5–15g) is generally safe for extended periods. However, consistent monitoring of one's health is prudent. The benefits of collagen typically appear gradually and fade if supplementation is stopped, indicating that ongoing use may be needed to maintain effects. Overall, the risks remain low for healthy individuals when using quality products within recommended guidelines.

Potential Risks: Food Source vs. Supplement


Feature	Collagen from Food Sources	Collagen from Supplements
Concentration	Lower, less concentrated; absorbed more slowly.	Higher, concentrated doses; may cause digestive upset.
Additives	Typically none, unless part of a prepared meal.	Can contain fillers, flavors, or other compounds; check labels.
Heavy Metals	Risk is generally lower; depends on animal's diet and environment.	Higher risk of contamination if from non-reputable sources or due to lack of regulation.
Allergen Risk	Known allergen risk based on consuming certain foods (e.g., fish, eggs).	Clear allergen risk if from a source you're allergic to; read labels.
Nutrient Synergy	Comes with a wide array of other vitamins, minerals, and amino acids.	Often isolated; sometimes fortified with specific vitamins (e.g., Vitamin C) for absorption.

Conclusion: Making an Informed Decision

While collagen offers potential benefits, being aware of the potential risks is essential. The likelihood of experiencing side effects is low for most healthy individuals, especially when choosing a high-quality product from a reputable brand. By prioritizing third-party tested supplements and starting with a low dose, users can minimize the risk of digestive issues or contaminants. Those with allergies to animal products, a history of kidney stones, or autoimmune conditions should proceed with caution and seek medical advice before starting. A proactive and informed approach ensures that you can safely incorporate collagen into your wellness routine and enjoy its potential benefits without unnecessary risks.

Visit a medical professional for personalized advice before starting any new supplement regimen.

Frequently Asked Questions

Individuals with allergies to the supplement's source (e.g., fish, eggs), people with a history of kidney stones or kidney disease, and those with autoimmune disorders should consult a doctor before taking collagen.

While generally safe for healthy kidneys, the hydroxyproline in collagen can increase oxalate levels, raising the risk of kidney stones in susceptible individuals or those with pre-existing kidney conditions.

Common side effects are usually mild and include digestive issues like bloating, nausea, heartburn, or diarrhea, and sometimes an unpleasant taste.

Always check the product label to identify the source of the collagen (e.g., bovine, marine, chicken) and avoid any product derived from an animal you are allergic to.

Due to a lack of FDA regulation, some collagen products may be contaminated with heavy metals. Choosing brands with third-party certifications (like NSF or USP) helps ensure purity.

Yes, for most healthy individuals, studies show that taking recommended doses of collagen peptides daily for extended periods is safe and well-tolerated.

There is limited evidence of drug interactions, but high protein intake can potentially interfere with certain blood pressure medications. Always consult a healthcare provider if you are on medication.