Which part of fish has the most collagen?

December 4, 2025 •

4 min read

According to research published in the journal Marine Drugs, some types of fish contain more collagen in their scales than their skin, making scales a surprisingly rich source. This discovery challenges the common perception that skin is the primary collagen-rich part and provides valuable insight for sourcing marine collagen.

Quick Summary

This article explores the specific parts of fish that are richest in collagen, comparing concentrations in the skin, scales, bones, and other by-products. It details the different types of collagen found in each part and discusses the bioavailability and extraction methods.

Key Points

Fish Skin: A historically popular and readily accessible source of marine collagen, with studies showing very high protein concentrations.
Fish Scales: Often discarded, scales can be surprisingly potent sources, with some research indicating higher dry mass collagen content than skin.
Fish Bones: Provide a high yield of collagen, mostly Type I, but require more extensive processing to separate the protein from minerals.
Bioavailability: Marine collagen from fish is absorbed more efficiently by the human body compared to collagen from bovine or porcine sources.
Sustainable Practice: Utilizing fish by-products like skin, scales, and bones for collagen extraction supports sustainability by reducing waste from the fishing industry.
Health Benefits: Marine collagen has been linked to improved skin health, wound healing, and anti-aging effects due to its high quality and absorption rate.

Understanding Marine Collagen Sources

Marine collagen has gained significant attention as a dietary supplement and a high-value ingredient in the cosmetics and food industries. Unlike bovine or porcine collagen, marine collagen does not carry the risk of transmitting diseases like bovine spongiform encephalopathy (BSE) and is free from the religious or cultural constraints associated with other animal products. The primary sources of marine collagen are the by-products of the fish processing industry, which include the skin, scales, and bones. Given that fish processing generates a substantial amount of waste, often ranging from 20% to 80% of the total fish weight, utilizing these by-products for collagen extraction represents an efficient and sustainable approach to waste management.

Fish Skin: A Leading Source of Type I Collagen

For many years, fish skin has been regarded as a premier source of collagen, particularly Type I, which is the most abundant form in the human body, providing structure to skin, bones, tendons, and ligaments. Scientific studies consistently report high concentrations of collagen in fish skin. A study comparing collagen content in Atlantic salmon and cod found that skin tissues contained the highest levels, at 89–98% of the total protein. While processing yields can vary depending on the fish species, age, and environmental factors, fish skin remains a highly reliable source for type I marine collagen.

Fish Scales: The Surprising Champion of Collagen Content

Contrary to common belief, fish scales can contain an extremely high concentration of collagen. For instance, a study on silver carp found that the swim bladder yielded 85.27% collagen, while the skin provided 69.45%, bones 41.47%, and scales 32.76%. A different study also found that salmon scales and skin had high collagen amounts, with scales having a higher concentration than skin. This makes fish scales, a product often discarded as waste, a surprisingly potent source of Type I collagen, proving valuable for biomedical and cosmetic applications due to its biocompatibility and antioxidant properties. The extraction from scales is, however, more complex due to their high mineral content, which requires an additional demineralization step.

Fish Bones and Cartilage: Diverse Collagen Sources

Fish bones are another significant source of collagen, containing high levels of Type I collagen similar to skin, but also exhibiting a more diverse composition of collagen types. Cartilage, particularly from certain fish like sturgeon and shark, is a rich source of Type II collagen, which is crucial for joint health and provides structural support to cartilage tissue. Bones typically contain 79–89% collagen relative to total protein content, making them a very high-yield source. Collagen can be extracted from bones to produce valuable products, such as gelatin or hydrolyzed collagen, though this often requires demanding processing steps like demineralization.

The Importance of Bioavailability

One notable advantage of marine collagen is its high bioavailability compared to bovine or porcine collagen. Marine collagen is absorbed by the body up to 1.5 times more efficiently due to its lower molecular weight and smaller particle size. This makes it more effective for health benefits, as it can be more readily circulated and utilized by the body. For example, fish collagen is known to support skin health, promote wound healing, and even demonstrate anti-aging properties.

Comparing Collagen Sources in Fish


Feature	Fish Skin	Fish Scales	Fish Bones	Fish Cartilage
Primary Collagen Type	Type I	Type I	Type I (diverse types found)	Type II (joint-specific)
Collagen Concentration	High (89–98% of total protein in some species)	Very high (up to 50% on dry mass)	High (79–89% of total protein)	High in certain species
Ease of Extraction	Relatively easier than bones and scales	More difficult; requires decalcification	Demanding process due to mineral content	Varies by species and tissue
Processing Yield	Variable, but generally good	Can be lower than skin, but compensates with concentration	Variable, extraction method-dependent	Varies greatly by species

Conclusion: The Best Source Depends on the Application

The research and extraction data show that while fish skin has historically been the most utilized source, parts like scales and bones also contain exceptionally high levels of collagen. Fish skin is an excellent, readily available source of Type I collagen, particularly from species like cod and salmon. However, scales can be a powerhouse of collagen, with some studies showing higher concentrations on a dry weight basis, though requiring more intensive processing. Ultimately, the ideal part of the fish depends on the specific end-use, with skin and scales being optimal for Type I collagen and cartilage best for Type II. For the average consumer looking to increase collagen intake, consuming whole, small fish like sardines or making a simple bone broth offers a convenient way to benefit from the collagen in skin, scales, and bones.

Visit the National Institutes of Health for more detailed studies on marine collagen research.

Frequently Asked Questions

While trace amounts of collagen are present in the muscle tissue or edible flesh of fish, the highest concentrations are found in the connective tissues like skin, bones, and scales, which are typically discarded during processing.

Yes, collagen derived from fish scales, like other marine collagens, is considered highly bioavailable. Its smaller particle size allows for more efficient absorption and utilization by the human body compared to some land-animal sources.

Marine collagen is preferred by many due to its higher bioavailability, lower risk of disease transmission (such as BSE), and absence of religious or cultural restrictions, making it a safer and more widely accepted supplement.

To increase your dietary collagen from fish, consider consuming small fish whole, like sardines, where you eat the skin, scales, and bones. Another effective method is making a nutrient-dense bone broth by simmering fish bones and connective tissues.

Yes, the collagen content and properties can vary by species, habitat (e.g., cold-water vs. warm-water), age, and the specific part of the fish. For instance, cold-water fish collagen typically has a lower denaturation temperature than that from warm-water fish.

The most common type of collagen found in fish skin, scales, and bones is Type I collagen, which is the same type abundant in human skin and bones. Fish cartilage, however, is a primary source of Type II collagen.

Yes, utilizing fish by-products for collagen and other high-value products significantly reduces waste from the fish processing industry, thereby mitigating environmental pollution and promoting a more sustainable and circular bio-economy.