Marine collagen is often presented as a clean and natural way to support the skin, hair and nails. However, the word “marine” does not automatically mean pure.
Marine collagen is produced using parts of fish and other marine animals, which may have been exposed to pollution and naturally occurring contaminants in the water around them.
Research has found arsenic, lead, cadmium, chromium and mercury in marine collagen supplements, with noticeable differences between brands.
If you take collagen every day, the quality and origin of that supplement matter.
Here, we look more closely at marine collagen toxicity, why heavy metals are a concern and why you may prefer to avoid marine collagen altogether.
What Is Marine Collagen?
Marine collagen is an animal-derived collagen that usually comes from the skin, scales, bones and connective tissues of fish.
These materials are processed and hydrolysed to break the collagen protein into smaller collagen peptides.
It is commonly marketed as a source of Type I collagen, which is the most abundant type of collagen in the human body.
However, marine collagen is not human collagen.
It contains animal-derived peptides that are digested into smaller peptides and amino acids before the body can use them.
The use of fish skin, scales and bones may help manufacturers make use of materials left over by the fishing industry, but it also ties the final supplement to the quality of the original marine source.
Why Is Marine Collagen Toxicity a Concern?
Fish live in environments that may contain pollutants, including heavy metals.
These substances can enter waterways naturally or as a result of mining, manufacturing, waste disposal and other human activity.
Once present in water, some contaminants can enter the aquatic food chain and accumulate in marine life.
The type and amount found in a fish can be influenced by its species, age, diet, location and position in the food chain.
Turning fish material into collagen does not automatically guarantee that every contaminant has been removed.
The purity of the finished supplement depends on several factors, including where the fish came from, which parts were used, how the collagen was processed and how thoroughly each batch was tested.
This is part of what makes marine collagen toxicity difficult for consumers to assess.
Heavy metals cannot be seen, tasted or smelled, and a polished label does not tell you what laboratory testing has found.
Marine Collagen Heavy Metals: What Has Research Found?
A 2025 study examined marine collagen supplements derived from fish and jellyfish for lead, cadmium, chromium, mercury and arsenic.
Arsenic was the most abundant element found, with an average concentration of 0.59 mg/kg.
Lead was the next most abundant, with an average concentration of 0.13 mg/kg.
Mercury was detected in 12% of the samples, and researchers found significant differences between brands.
None of the products tested exceeded the relevant EU regulatory limits, and the estimated daily exposure remained below established tolerable daily intake levels when the products were consumed at their recommended doses.
However, this doesn’t mean that every product was free from toxic metals.
The study confirmed that these contaminants can be present in marine collagen and that levels vary between products.
The researchers also recommended that food safety regulations be updated to consider the possible cumulative risk created by consuming multiple contaminated supplements.
This distinction matters. Staying below a regulatory limit is not the same as containing no detectable contaminants.
Regulatory thresholds are intended to restrict exposure, but consumers may also encounter heavy metals through food, drinking water, environmental pollution and other supplements.
A test result also only reflects the particular product or batch examined.
Differences between brands demonstrate why responsible sourcing, manufacturing controls and ongoing batch testing are so important.
Why Are Heavy Metals a Problem?
The health risk created by a contaminant depends on the substance, its chemical form, the amount consumed and the length of exposure.
A detectable trace does not automatically mean that a product will cause poisoning, but repeated exposure to certain substances can contribute to the amount that accumulates in the body.
Lead is a cumulative toxicant that can affect several body systems. The World Health Organization states that there is no level of lead exposure known to be without harmful effects.
Mercury can affect the nervous, digestive and immune systems, as well as the lungs, kidneys, skin and eyes. It is of particular concern during pregnancy and early childhood because of its potential effects on development.
Cadmium can accumulate in the body over time and has been associated with damage to the kidneys, bones and respiratory system. The body removes cadmium very slowly, making long-term exposure an important consideration.
Arsenic requires a little more context because it exists in different forms. Inorganic arsenic is highly toxic, while the organic arsenic compounds commonly found in seafood are generally considered less harmful. Tests that only report total arsenic may not show how much of each form is present.
This doesn’t mean that taking a marine collagen supplement will automatically expose you to a dangerous dose, but it does mean that consumers should not assume a product is completely pure simply because it comes from the sea or falls within a legal limit.
Can Processing Remove Heavy Metals From Marine Collagen?
Manufacturers can use purification and quality-control processes to reduce contaminants.
However, processing methods and testing standards can vary between suppliers and products.
Statements such as “wild-caught”, “clean”, “natural” or “premium” don’t prove that a supplement has been independently tested for arsenic, lead, cadmium and mercury. Even knowing the species or fishing location does not replace laboratory analysis of the finished product.
Reliable testing should cover the product people actually consume, not only the original fish material. Ideally, manufacturers should be able to provide recent, batch-specific results from an accredited independent laboratory.
Without those results, it can be difficult to know how carefully the raw ingredients have been sourced or what remains in the finished supplement.
Why Avoid Marine Collagen?
There are several reasons you may decide that marine collagen is not right for you.
You Want To Avoid Potential Marine Contaminants
Research confirms that toxic metals and metalloids can be detected in some marine collagen supplements.
Although responsible sourcing and testing can reduce the risk, they cannot be judged from marketing language alone.
Choosing a formula that does not contain fish-derived collagen removes marine collagen as a potential source of exposure.
You Have a Fish Allergy
Marine collagen is sourced from fish and may not be suitable for people with fish allergies.
Processing may reduce some allergenic proteins, but it does not guarantee that every trace will be removed.
Allergic reactions to fish collagen have been documented, including a published case of anaphylaxis caused by fish collagen in gummy tablets.
Anyone with a known fish allergy should speak to a qualified medical professional before using a marine collagen supplement.
You Follow a Vegan or Vegetarian Diet
Marine collagen is an animal product. It may be described using language that focuses on the ocean, sustainability or natural beauty, but it is still obtained from the bodies of fish or other marine animals.
It’s therefore unsuitable for vegans and vegetarians, as well as people who want their beauty and wellness routines to be free from animal-derived ingredients.
You Want Greater Clarity About What You Are Taking
Supplement labels can make it difficult to identify the species, location and exact tissues used to produce marine collagen.
Some products provide clear sourcing and laboratory information, while others rely on vague claims about purity.
If a manufacturer cannot provide clear information about sourcing, batch testing and contaminant levels, you are being asked to trust a product without being shown the evidence behind it.
Is All Marine Collagen Toxic?
It wouldn’t be accurate or fair for us to say that every marine collagen supplement is toxic or unsafe.
Available research includes products that remained within regulatory limits, as well as samples in which no toxic metals or metalloids were detected.
The concern is that marine collagen can contain these substances; levels can differ significantly between brands, and consumers may have no easy way to assess the purity of a particular product.
Marine collagen should not be assumed to be toxic, but it should not automatically be assumed to be clean or contaminant-free either.
If you’re taking a supplement every day, that uncertainty may be enough to make a plant-based alternative feel like the more suitable choice.
A Plant-Based Alternative to Marine Collagen
At Arella, we saw the research, understood the risks, and chose a completely different approach.
Arella Vegan Liquid Collagen doesn’t contain collagen extracted from fish, cattle or other animals.
It’s formulated with VeCollal®, a vegan amino acid complex designed to exactly match the amino acid profile of human Type I collagen.
Instead of providing hydrolysed pieces of animal collagen, VeCollal® provides a precise combination of amino acids associated with human Type I collagen.
The formula also contains Vitamin C, which contributes to normal collagen formation for the normal function of the skin.
As Arella Collagen doesn’t use fish-derived ingredients, it avoids the marine collagen supply chain and the associated fish-allergy risk.
It’s completely vegan and provides an alternative for people who don’t want their daily collagen support to depend on animal tissues.
Making a More Informed Choice about Collagen
Marine collagen is often promoted for what it may offer, but we believe consumers deserve to understand where it comes from and what else it could contain.
Research has demonstrated the presence of arsenic, lead, cadmium, chromium and mercury in marine collagen supplements.
Although the amounts recorded remained within EU regulatory limits, the variation between brands and the possibility of cumulative exposure should not be ignored.
For people who want to avoid fish-derived collagen, animal ingredients and the possibility of marine-sourced contaminants, Arella offers a carefully formulated, plant-based alternative.
We believe you deserve wellness without worry, and we’re here to look after you from the inside out.
