Can Taking Collagen Hurt You? Understanding the Risks and Side Effects

December 18, 2025 •

4 min read

While collagen supplements are widely praised, studies indicate some people may experience side effects such as mild digestive upset. This raises the important question: Can taking collagen hurt you? We delve into the potential risks and who should be cautious before adding this popular supplement to their routine.

Quick Summary

This article explores the rare but possible adverse effects of collagen supplementation, including digestive discomfort, potential allergic reactions, and kidney health risks for vulnerable individuals.

Key Points

Generally Safe: For most healthy people, collagen supplements are considered safe with minimal risk of harm when taken at recommended doses.
Digestive Issues are Common: Mild side effects like bloating, gas, heartburn, or diarrhea can occur, especially when starting a new supplement.
Allergy Risk: Individuals with allergies to fish, shellfish, beef, or eggs should check the source of their collagen to avoid allergic reactions.
Kidney Concerns for Some: Those with a history of kidney stones or kidney disease should be cautious, as collagen contains an amino acid that can increase oxalate levels and contribute to stone formation.
Choose a Quality Product: Supplements are not FDA-regulated, so it is crucial to select a third-party tested product to ensure purity and avoid heavy metal contamination.
Consult a Doctor: Pregnant or breastfeeding individuals and those with pre-existing conditions should consult a healthcare provider before using collagen.

Is Collagen Safe for Everyone?

For the vast majority of healthy individuals, collagen supplements are safe and well-tolerated when taken at recommended dosages. Collagen is a protein naturally found in the body, and supplemental forms are typically peptides derived from animal sources like bovine, marine, or chicken. However, safety is not universal, and potential risks exist, particularly for certain individuals or when used improperly.

Common Side Effects to Watch For

While serious side effects are rare, some people may experience mild, temporary issues, especially when first starting supplementation or taking high doses. The most common issues are often related to the digestive system.

Digestive Discomfort

Bloating and gas: Some users report a feeling of fullness or abdominal bloating. This may be caused by the body adjusting to the new protein intake or the presence of other ingredients in the supplement.
Mild diarrhea or constipation: Changes in bowel habits, such as mild diarrhea or constipation, have been reported by a small number of people. Choosing a highly hydrolyzed collagen product can improve digestibility and absorption.
Unpleasant aftertaste: Particularly with marine collagen, some people note a lingering fishy or unpleasant aftertaste. This can often be masked by mixing the powder with strongly flavored liquids like juice or smoothies.

Allergic Reactions

One of the most significant risks is allergic reactions, which are possible due to the animal origin of most collagen supplements. Individuals with known allergies to fish, shellfish, beef, or eggs must carefully read product labels. In rare cases, severe allergic reactions like anaphylaxis can occur, though it is not common. Signs of an allergic reaction include rashes, swelling of the mouth or face, and difficulty breathing.

Risks for Vulnerable Groups

While generally harmless for most, certain health conditions or life stages require extra caution or avoiding collagen altogether.

Kidney Stone Risk

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, particularly in individuals with a history of kidney issues or at higher risk. Healthy individuals who stay well-hydrated are typically not at high risk, but those with existing kidney problems should consult a doctor before supplementing.

Contamination Concerns

Because dietary supplements are not strictly regulated by the FDA, the risk of product contamination exists. Some third-party tests have found heavy metals like lead, cadmium, and arsenic in some collagen products. To minimize this risk, look for products that have been third-party tested and certified by reputable organizations.

Pregnancy and Breastfeeding

There is insufficient research to confirm the safety of collagen supplements for pregnant or breastfeeding women. It is recommended to avoid supplementation during this time unless explicitly advised by a healthcare provider.

Potential for Overdose

While a severe collagen overdose is extremely rare, taking excessively high doses can exacerbate mild side effects like digestive upset. For those with underlying autoimmune conditions like systemic scleroderma, an excess accumulation of collagen is already a concern, and supplementation should only be done under strict medical supervision. Long-term effects of very high doses are not well-researched, so it is best to adhere to the manufacturer's recommended daily intake.

Comparison of Collagen Supplementation Risks and Benefits


Aspect	Potential Risks	Potential Benefits
Digestive System	Bloating, gas, mild diarrhea, or constipation in some individuals.	May help heal the intestinal lining and improve gut health.
Allergies	Risk of allergic reactions if allergic to source (fish, beef, etc.).	None, allergic reactions are a negative outcome.
Kidney Health	Increased risk of kidney stones for predisposed individuals due to oxalate conversion.	Supports bone health, which is vital for overall skeletal structure.
Supplement Quality	Risk of heavy metal or toxin contamination due to lack of FDA oversight.	Quality, third-party tested products are generally considered safe for healthy people.
Joints	Rare reports of joint pain with excess collagen.	May relieve joint pain and stiffness in osteoarthritis sufferers.

How to Minimize Risks

To safely incorporate collagen into your routine, follow these guidelines:

Choose wisely: Opt for reputable brands that provide transparency about their sourcing and production process. Look for third-party testing certifications, such as from the Clean Label Project.
Start small: Begin with a low dose and gradually increase it to the recommended amount to allow your body to adjust. This helps to mitigate digestive issues.
Stay hydrated: Adequate fluid intake is crucial, especially for those at risk of kidney stones.
Consult a professional: Always speak with a healthcare provider before starting any new supplement, particularly if you have pre-existing medical conditions, are pregnant, or are taking other medications.
Listen to your body: If you experience persistent or concerning symptoms, discontinue use and consult a doctor.

Conclusion

For the average person without underlying health issues, taking collagen is overwhelmingly safe and poses a low risk of harm. The most common adverse effects are mild and digestive in nature. However, certain groups, including those with allergies to animal products, a history of kidney stones, or those who are pregnant or breastfeeding, must proceed with caution. The key to safe supplementation is to choose a high-quality, third-party tested product, adhere to recommended dosages, and, when in doubt, consult with a healthcare professional to ensure it is the right choice for you. While collagen holds promise for improving skin, joint, and bone health, balancing these benefits against potential risks is essential for a safe wellness journey. More research is needed, especially regarding long-term high-dose use and the interaction with other supplements.

Disclaimer: The information in this article is for educational purposes only and is not a substitute for professional medical advice. Always consult your doctor before starting any new supplement.

Visit Healthline for more details on collagen benefits and side effects

Frequently Asked Questions

The most common side effects are mild and typically related to the digestive system. These include bloating, gas, feelings of fullness, mild diarrhea, and sometimes an unpleasant taste in the mouth.

For most healthy people, consuming collagen in moderation is unlikely to cause kidney stones. However, collagen contains hydroxyproline, which is converted to oxalate, potentially increasing kidney stone risk in those with a history of kidney issues or at high risk.

People with allergies to the collagen source (e.g., fish, beef), a history of kidney stones, pregnant or breastfeeding women (due to lack of research), and those with certain medical conditions should consult a doctor or avoid collagen.

No, collagen supplements are not regulated by the FDA. It is important to choose brands that undergo third-party testing to ensure product quality and check for contaminants like heavy metals.

Yes, although rare, allergic reactions are possible, particularly if the collagen is sourced from an animal to which you are allergic (e.g., marine collagen if you have a fish or shellfish allergy). Symptoms can include rashes, swelling, and difficulty breathing.

While an outright overdose is rare, taking excessive amounts of collagen can lead to digestive discomfort and may place a strain on the kidneys. It is best to stick to the recommended dosage on the product label.

While there are few known interactions with collagen itself, supplements often contain other ingredients that could interact with medications. It is always wise to consult a healthcare provider before starting supplementation if you are on medication.