Nutrition Diet: What ingredients should be avoided in collagen?

October 30, 2025 •

4 min read

A 2020 study by the Clean Label Project found that a significant number of top-selling collagen supplements contained measurable levels of heavy metals, such as arsenic and lead. For consumers, understanding what ingredients should be avoided in collagen supplements is crucial for making a safe and effective nutritional choice.

Quick Summary

To ensure a quality and safe supplement, consumers should avoid collagen products with heavy metal contamination, unnecessary artificial additives, excessive sugar, fillers, and potential allergens.

Key Points

Avoid Heavy Metal Contamination: Choose collagen that is third-party tested for heavy metals like lead, arsenic, cadmium, and mercury to prevent potential health risks from environmental toxins.
Reject Artificial Additives: Steer clear of supplements with artificial flavors, colors, and sweeteners, as these can be inflammatory and indicate a lower-quality product.
Ensure Clean Sourcing: Opt for collagen derived from ethically sourced animals, such as grass-fed bovine or wild-caught marine sources, to reduce the risk of contamination.
Watch for Unnecessary Fillers: Avoid products that use fillers and bulking agents like cellulose, which add no nutritional value and can impair absorption.
Choose Hydrolyzed Collagen: Select hydrolyzed collagen peptides for optimal absorption, as un-hydrolyzed collagen is too large for the body to use efficiently.
Check for Hidden Sugars: Be mindful of sweetened collagen products, especially gummies and drink mixes, which can contain high levels of added sugar.

Navigating the world of nutritional supplements can be challenging, and collagen is no exception. With its rise in popularity for supporting skin, hair, and joint health, the market has become saturated with products of varying quality. Knowing what ingredients should be avoided in collagen can help you bypass potentially harmful contaminants and ineffective formulas.

The Serious Threat of Heavy Metal Contamination

One of the most significant concerns with collagen supplements is the potential for heavy metal contamination. Collagen is derived from animal parts like hides, bones, and fish scales. These animals can absorb environmental toxins, which can then become concentrated in the final product through sourcing and processing.

Common heavy metals to watch out for include:

Arsenic: A known carcinogen, chronic exposure to arsenic is linked to an increased risk of cancer, cardiovascular disease, and skin lesions.
Lead: Toxic even at low levels, lead can cause neurological damage, kidney damage, and other developmental and cognitive issues.
Cadmium: This metal can lead to kidney damage and bone demineralization, weakening bones over time.
Mercury: Particularly a risk in marine-sourced collagen, mercury can cause neurological and developmental problems.

To mitigate this risk, consumers should seek out products that have undergone rigorous third-party testing and provide transparent lab results or a Certificate of Analysis (COA). Ethical sourcing, such as from grass-fed, pasture-raised, or wild-caught sources, also reduces the risk of contamination.

Unnecessary Artificial Additives and Fillers

Many collagen products, particularly flavored powders and gummies, contain unnecessary ingredients that can do more harm than good. A pure collagen supplement should have a minimal ingredient list, ideally containing only hydrolyzed collagen peptides.

Ingredients to avoid for a cleaner product:

Artificial Flavors and Sweeteners: These are added to improve taste but can affect the overall quality. Common examples include sucralose and other chemical flavorings.
Artificial Colors: Often used for marketing appeal, artificial dyes provide no nutritional benefit and can be inflammatory.
Fillers and Bulking Agents: Ingredients like cellulose, starch, and silicon dioxide are used to bulk up powders and cut costs. They can interfere with absorption and may cause digestive issues.
Emulsifiers: Substances such as xanthan gum and carrageenan are used for texture and stability. Studies suggest these may disrupt intestinal homeostasis and contribute to inflammation.

Sourcing Concerns and Potential Allergens

For many, the source of collagen is a key consideration due to dietary restrictions or allergies. Most collagen is derived from animals, posing a risk for individuals with specific sensitivities.

What to look for and what to avoid:

Source Transparency: Always check the label to see if the collagen is from bovine, marine, or chicken sources. If the supplement is made from marine collagen, it should specify the type of fish.
Allergen Alerts: People with fish, shellfish, or egg allergies must be particularly cautious. The processing of collagen can potentially leave traces of allergens, and some manufacturers fail to list the specific animal parts used.
Poor Sourcing Practices: Collagen from animals raised in Concentrated Animal Feeding Operations (CAFOs) is a red flag. These animals are more likely to have accumulated contaminants from their feed and environment. High-quality, ethically sourced collagen comes from grass-fed or wild-caught animals.

Ineffective Formulation: High Sugar and Low Bioavailability

Beyond contaminants and additives, some collagen products are simply ineffective due to their formulation.

Substandard product characteristics to avoid:

Hidden Sugars: Gummy supplements and pre-mixed collagen drinks often contain significant amounts of added sugar, counteracting potential health benefits.
Low Collagen Content: Some brands contain a surprisingly low amount of collagen per serving. To be effective, most research suggests a daily intake between 5 and 15 grams of hydrolyzed collagen peptides.
Un-hydrolyzed Collagen: The body can’t efficiently absorb collagen in its native, long-chain form. Hydrolysis, which breaks it down into smaller peptides, is essential for bioavailability. A product not labeled as 'hydrolyzed' or 'collagen peptides' may offer minimal benefits.

Comparison: High-Quality vs. Low-Quality Collagen


Feature	High-Quality Collagen	Low-Quality Collagen
Sourcing	Ethically sourced, grass-fed bovine, wild-caught marine	Poorly sourced animal products (CAFOs), unspecified animal parts
Heavy Metals	Independently tested, verified heavy metal-free with COA	Potential for contamination with lead, arsenic, cadmium, mercury
Additives	Minimal, simple ingredient list. May include vitamin C or hyaluronic acid	Contains artificial flavors, colors, sweeteners, and unnecessary fillers
Formulation	Hydrolyzed collagen peptides for optimal absorption	Un-hydrolyzed collagen or low protein content, poor absorption
Sugar	No added sugars or excessive sweeteners	High in added sugars, especially in gummies and drinks
Transparency	Clear label information on sourcing, testing, and ingredients	Vague sourcing, no independent testing results

How to Choose a Clean Collagen Product

Making an informed decision requires careful consideration beyond brand recognition. The key is to prioritize transparency and quality.

Read the Label: Examine the ingredient list for anything other than hydrolyzed collagen peptides and possibly beneficial co-factors like vitamin C. The fewer the added ingredients, the better.
Verify Third-Party Testing: Look for certifications from reputable third-party organizations that test for heavy metals and contaminants. Many companies provide a Certificate of Analysis (COA) on their website.
Investigate the Sourcing: High-quality brands are proud of their ethical sourcing. Look for descriptions like “grass-fed, pasture-raised bovine” or “wild-caught marine”.
Check for Bioavailability: Ensure the product is labeled “hydrolyzed” or “peptides” for efficient absorption by your body.
Be Wary of "Miracle" Claims: If a product's promises sound too good to be true, they probably are. Consistent, long-term use is key to seeing results from collagen supplementation.

Conclusion

While collagen offers potential benefits for skin, joint, and bone health, the purity and quality of your supplement matter immensely. The risks associated with heavy metal contamination, ineffective formulation, and unnecessary additives are not worth compromising your health. By carefully scrutinizing ingredient labels, confirming third-party testing, and opting for transparent sourcing, you can choose a clean and effective collagen product. This diligent approach ensures your nutrition diet truly supports your wellness goals.

Optional outbound link: The True Content and Faces Behind America's Best-Selling Collagen - Clean Label Project

Frequently Asked Questions

Heavy metals can be present in collagen supplements because the raw materials—animal hides, bones, and fish—can accumulate environmental toxins. Animals raised in polluted areas or in Concentrated Animal Feeding Operations (CAFOs) are at higher risk.

The best way is to look for a product that has been third-party tested by an independent laboratory. Reputable brands will display certifications or provide a Certificate of Analysis (COA) confirming the absence of heavy metals.

Fillers like maltodextrin and silicon dioxide are often used to bulk up powders and lower production costs. They add no nutritional value, can interfere with nutrient absorption, and some have been linked to digestive issues.

Yes, many collagen gummies contain high amounts of added sugars, artificial sweeteners, and artificial colors to make them palatable. For those monitoring sugar intake, a pure powder is a better choice.

True collagen is only found in animals. However, there are vegan 'collagen boosters' that contain plant-based ingredients, vitamins (like Vitamin C), and amino acids to support the body's natural collagen production. These are a good alternative for vegetarians and vegans.

Hydrolyzed collagen, or collagen peptides, has been broken down into smaller, more digestible molecules through a process called hydrolysis. This smaller size allows the body to absorb and use the protein more efficiently than non-hydrolyzed collagen.

If you have a known allergy, you must avoid marine collagen supplements. Always check the ingredient label to confirm the source (bovine, chicken, or marine) to prevent a potential allergic reaction.

Vitamin C is an essential co-factor in the body's natural collagen synthesis process. While not an ingredient to avoid, it is an important addition. Many high-quality supplements include it, or you can take it separately.